Surface Pro 3 - Excessively loud fan, constant overheating during idle and light tasks (now on my second, third, fourth Surface Pro 3 i7) Yea, there's definitely a problem. 4 engines are V-8 and have a displacement of 7. Eventually a bad shutter can break loose and get stuck down in the exhaust pipe or in the drives exhaust passage. Engine overheats at dead idle 600 rpm. FAST EZ-EFI Marine Self-Tuning Master Kit with Mercury Marine O2 Installation. They have flushed the rad, but I suspect the heater core isn't flushed very well, cos they dont want to listen to me and do as I tell them. On low RPM (idle) after the engine has warmed up the water telltale is on and off and there is no uniform stream of water out of it. Im assuming thats because its at 4k rpms. To summarize, at idle, no bubbles, at plane speed, (sorry, tach is broken) guessing 2000-2500 RPM, the bubbles are fast and furious. Stop engine immediately, check the oil level Run engine only in emergency. 0 mercruiser; high idle 6. Basically, the air conditioning does not blow cold air if the car is idling, only when in motion. A downloadable repair manual is a digitally delivered book of instructions providing step-by-step repair procedures, maintenance and a troubleshooting guide. These forums were a lot of help, and read through most of the posts on overheating. Keep in mind that there may be more than one reason a 4. I took the boat out on a test drive at the dealer, and it seemed nice. our first launch. 7 L engine that is overheating, Changed impeller and thermostat. When you get to 240, that's when you are going to start having problems. I could idle all day in hot weather and it would never run hot but 15 minutes at highway speed and it would overheat. When that spring gets compressed (less springy) over time, it leads to overheating at idle (only). Some people from another forum mentioned that the thermostat and/or temp switch could be bad also. To check a car's coolant levels, allow the car to cool and open the radiator cap. Additionally, some cars have a fan clutch that may cause overheating. 2003 Correct Craft with 5. Overheating Mercruiser Alpha One Gen 1- Just in time to ruin 4th plans! briefly run motor at idle and 1500 rpm and view/measure the flows. Oh, yeah, like Admin said, check your coolant level. There are multiple reasons why your vehicle’s engine overheats or its temperature shoots up. com is located in Shelby Township, Michigan (Detroit area). I'm having an issue with overheating on my 65 289 4V. That said, I'm wondering about the mechanic's diagnosis, overheating at idle could also be caused by reduced coolant circulation (perhaps due to a water pump with a badly eroded impeller) or by a lack of airflow over the radiator at idle which could be caused by a fan failure or by something blocking the radiator. so my a/c only works when its running. Water should be visible at the top of the radiator. Overheating at idle after driving I've been having some overheating troubles the past week or so, where pretty much I can drive the car for a while and it's fine, boost to wastegate pressure, drive some more, and park and idle. This means your head gasket has to seal both extremely hot, high-pressure combustion gases as well as engine coolant which can be anywhere from cold ambient temperatures to the normal operating temperature of your engine. Cylinder heads and block checked out good at overhaul, but that still leaves manifolds as a possibility. Stop engine immediately, check the oil level Run engine only in emergency. My 1530 has recently been overheating when left idle for a while(30 min or so). My temps will drop 1-2 degrees while reving in Idle (rev to about 3-4k RPMS). Designed and built exclusively by Mercury MerCruiser and available only from Mercury MerCruiser, the MX 6. A downloadable repair manual is a digitally delivered book of instructions providing step-by-step repair procedures, maintenance and a troubleshooting guide. No AC at idle / engine overheat On hot days, the AC is nice and cold when at highway speeds, engine temp runs normal. Outboard boat motors are notorious for problems. By chance is it a Robert Shaw unit? The only DOA thermostat I ever bought was a Shaw. The fan goes on and the CPU throttles but nothing succeeds in lowering the temperature. To check a car's coolant levels, allow the car to cool and open the radiator cap. Inboards, Bravo, TRS and all the Speedmaster drives have a separate intake pump on the engine. I tried to idle it to the point of overheating the other day, and the fan kicked on; the A/C even blew cold. I have hot air in the front and rear heaters. Any suggestions, any info would be appreciated. 2003 Correct Craft with 5. drops to what it should. With the 13' she will be "slow" but should have too much RPM - IF she makes only 4000 RPM with a 13' prop only there is something else wrong. This is in 80 degree weather with the A/C running full blast. It continued to overheat, so back to the shop it went. Still overheats after about 20 minutes of running idle or full speed. The risers were only 2 years old, and still in good condition, so put it back together. Mercruiser Water Pump Impeller Replacement Instructions This video includes step by step instructions regardingperfprotech. ), Radiator Fan, Thermostat, or something else. The dealer said it needed the heads reworked ($4500). Any help would be appreciated. The flow seemed a little weak but when I increased the rpm it increased. I always try and wait for the temp to drop below 470° before shut down. 7 L engine that is overheating, Changed impeller and thermostat. (kit) Depending on how hot the engine got, you may have other problems such as burnt exhaust flappers, a dropped valve, and/or partially melted shift cable, etc. Check the fan relay and fuse. I'm forced to shut it off or it will start to boil the the coolant and cause damage. MerCruiser Overheating - Merc Cruiser Troubleshooting Guide Troubleshooting can determine faults and help correct mechanical or cooling system problems. As soon as I go down the road the temp. It sounds when i shut off the boat. driving no problem. Mercruiser's technical bulletin recommends water at half-way valve open and idle at 1300 RPM until warm up. 5k RPM's) Description: When having the bike idle for 5-10 minutes, the temperatures will reach 250+ degrees. Keep in mind that there may be more than one cause to an overheating issue. Twenty Reasons Why Your Engine is Overheating In this Truck Radiator guide we are going to go over 20 reasons why your engine may be overheating. Temp is normal if at 1000 or above. ECT overheat ECM memory Multiple CAN Circuit faults Engine oil pressure NOTE: Excludes 6. On very hot days and nights while I'm sitting at a light or in a drive-thru my temperature hand starts going up about 3 dashes pass 200. If it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and let the engine idle. I drive a 2013 Chevy Sonic. Overheating problems due to the head gasket may also be due to a break in the head gasket that is allowing combustion gasses to be pushed into the coolant. I'm having an issue with overheating on my 65 289 4V. Mercruiser Alpha 1 Overheating only at idle. Location Of Third Drain Plug On 5 0 Mpi Mercruiser Boat. Stern Drive overheating at idle - some of you have to own boats too I have an OMC stern drive 5. Mercruiser Overheat Problem. Mercruiser Wiring Diagram 3. finally - 2001-2004 Toyota Sequoia. As soon as I go down the road the temp. The only real fix for overheating on the 99 is an electric fan conversion. A downloadable repair manual is a digitally delivered book of instructions providing step-by-step repair procedures, maintenance and a troubleshooting guide. I have changed water pump, hoses, and thermostat, flushed radiator. 4 mercruiser engine to overheat pre ignition in a mercruiser 4. Engine overheats at dead idle 600 rpm. MerCruiser Overheating - Merc Cruiser Troubleshooting Guide Troubleshooting can determine faults and help correct mechanical or cooling system problems. When testing for the first time in the water, It overheated, alarm went off. I tried to idle it to the point of overheating the other day, and the fan kicked on; the A/C even blew cold. 1 day ago · I have also experienced similar issues after the upgrade to Mac OS Catalina, my issues still occur even after a full wipe and fresh install alongside a reset of NVRAM and SMC, it happens at idle and and gets worse as applications are used though no freezing occurs the fans ramp up higher than I've ever heard and the computer runs hot. Obviously the issue is not obstruction but bubbles. Mercruiser 5. There are many causes of engine overheating and while we won't go over all of them, we will point out some of the main causes of engine overheating and point you in the right direction […]. Troubleshooting starting and running problems can sometimes be quite difficult. This is an easy one. Re: another Mercruiser overheat investigation « Reply #98 on: June 06, 2017, 10:59:02 AM » ok finally managed to find it - the ONLY model not listed in my clymer was the one I was working on - had to remove the whole manifold to get into the stat housing at the exhaust elbow -. What could cause a PT Cruiser to overheat and blow water out of the surge tank only at idle and when it is possible for heat from combustion to cause an engine to overheat quickly depending on. Improper repair to a MerCruiser engine can render it unsafe or result in further damage. ), Radiator Fan, Thermostat, or something else. It only overheats when its driven, i can idle it and it wont get hot, but as soon as i take off it starts warming up and eventually get up to about 230. Most cars have fans, either electric or mechanical, that force air through their radiators. But as soon as I pull up to a stoplight, with the engine idling, the AC starts blowing warm air and the temp gauge spikes up. If it only overheats at idle but not when rolling down the road, the thermostat isn't stuck closed. At idle is where it starts to take a crap. 5 impreza's and they are both showing the exact same symptoms at just over 100,000 kms. They have flushed the rad, but I suspect the heater core isn't flushed very well, cos they dont want to listen to me and do as I tell them. 496 MerCruiser Engine Overheating 2001-2007 When a MerCruiser engine overheats, catastrophic damage to the engine will occur if the cause isn't repaired immediately. 0, overheating at idle. This is called a High Speed Overheat. I recently had a problem with the 302 in my 1972 Bronco overheating at idle after it had not been started for several months. Shifting can be easy once you know the basics and have practiced a little. 0 fouling# 7 spark plug at idle; adjust idle on 2006 5. I purchased a boat with what ended up being a blown 1989 Mercruiser 4. 6 psi at idle and over 20 at WOT. confirmed that clutch does lock. Dodge Truck & SUV forum with the best tech and vehicle help on the web. the problem is the car overheats at idle, or slow traffic, which there's a lot of in so cal. Am not sure if sticky/stuck valves can cause poor running and overheating. May need flush/backflush treatments, possible new radiator. Thats the short answer. Overheating at slower speeds, like stop light to stop light, could mean your cooling fan isn’t pulling enough air. My 1530 has recently been overheating when left idle for a while(30 min or so). This makes a difference in what thermostat housing is used with which pump. Any good Fresh Water Cooling System should have excess cooling capacity. 0 mercruiser overheat at idle; can mercruiser overheat at idle due to old spark plugs and wires? engine surging at idle on a 5. So I know it can only be a few culprits 15-20k ago in it's 90k life, I got into an accident; the entire front end was redone (radiator, hoses, etc). I'm having problems with my 1992 MerCruiser 4. Pretty confident the impeller is working ok so i replaced the t-stat. impeller has been - Mercury Boating question Check your idle rpm. The gauge is going 3/4 of the way and the overflow tank is literally full of boiling fluid and waiting to explode. Is the only plausible cause the fan. It may be time to get into the pickup system as it could be a flapper or pinched. I have a 79 Sea Ray with a 470 Mercruiser. I'm having an issue with overheating on my 65 289 4V. No AC at idle / engine overheat On hot days, the AC is nice and cold when at highway speeds, engine temp runs normal. The air coming out of the vent also goes from cold to warm. 2003 Correct Craft with 5. More pressure than that on muffs will only shoot water out the sides of the muffs. To summarize, at idle, no bubbles, at plane speed, (sorry, tach is broken) guessing 2000-2500 RPM, the bubbles are fast and furious. 1987 - 1996 F150 & Larger F-Series Trucks - Overheating only at highway speeds - I have 1990 F250 with a 5. 225 is not overheating. When I put the van. Hg (7 kPa) maximum at idle rpm, 3000, full throttle and back at idle rpm. There are multiple reasons why your vehicle's engine overheats or its temperature shoots up. The longer answer is a clogged raditor fins with too many bugs stuck between the fins. Hi I have a Mercruiser 5. Overheating Mercruiser Alpha One Gen 1- Just in time to ruin 4th plans! briefly run motor at idle and 1500 rpm and view/measure the flows. Good Luch. I've got an overheating problem at idle which I can't seem to solve. I'd r&r that just to be sure. It will redline, the check guages light comes on, and it starts spewing coolant. The fan at 600RPM engine idle speed just isn't enough sometimes. framingjohndeloreanfilm. This plate is about 1" wide X 2" tall and it is usually pinned to the stb side of the block towards the rear. APPLICATION. Mercruiser Water Pumps. Close the bleeder screw and take off the coolant overflow tank cap. Still, I only have couple hours on the engine since it was rebuilt, so I can not say for sure that #7 is now dry. Measured my 106 drive and I am only getting 8gpm at idle?? Can you tell me what pump is in the 106 drive as Mercruiser uses a hi pressure, low volume pump in old model Gen l and a lo pressure , hi volume pump in Gen ll. I have small taps at the bottom of each exhaust manifold. Have standard 4. But as soon as I pull up to a stoplight, with the engine idling, the AC starts blowing warm air and the temp gauge spikes up. Bad shutters will only make noise at or just above idle. 1973 - 1979 F-100 & Larger F-Series Trucks - overheats while driving, not at idle. It's detroit iron so anyone experienced with old-school engines I could use your help. I'm forced to shut it off or it will start to boil the the coolant and cause damage. Pretty confident the impeller is working ok so i replaced the t-stat. On low RPM (idle) after the engine has warmed up the water telltale is on and off and there is no uniform stream of water out of it. Re: Mercruiser 7. so my a/c only works when its running. Replaced thermostat & coolant. Although they were sure this would help, they did the work. 2 mercruiser engine; how hot should a mercruiser iboard. Look on the ground underneath your engine and inspect for a coolant leak. i was thinking that i know i need. Hey guys i have a 62 fairlane, and i put a 289 from a 64 fairlane, im having overheating isues. Confirm it is overheating by measuring with a meat/candy thermometer, in case coolant is simply being pushed out. Once I cut the throttle back it spits water almost right away. always remained in the middle/center of the gauge while driving and while idle. Hot oil is not the only reason for low idle. ECT overheat ECM memory Multiple CAN Circuit faults Engine oil pressure NOTE: Excludes 6. If you find you're too fast an idle speed, rough idle or stalling, misfiring on acceleration or adjustments to your carburetor seem to have limited effect than you may have a vacuum leak causing overheating. My wifes 15F gets hot and pisses steam after you idle for 2-3 minutes - WOT is fine. 2L sterndrive. The last time we ran her she overheated. March 30, 2011 the lack of heat at idle may be due to a faulty auxiliary water pump. 6 4cyl) with about 73k miles has started overheating at idle probably about 5k miles ago. The electric fan will only come if i unplug the connector to the cts then it causes the engine to run rough. Shifting can be easy once you know the basics and have practiced a little. 7 L engine that is overheating, Changed impeller and thermostat. 496 MerCruiser Engine Overheating 2001-2007 When a MerCruiser engine overheats, catastrophic damage to the engine will occur if the cause isn't repaired immediately. Generally they can do so at high enough quantities that the vehicle does not need to move to exchange enough heat from radiator to the atmosphere to assure. Was overheating on me, i replaced the impeller. First time out, heated straight up at idle, no cooling at higher RPM. I have changed water pump, hoses, and thermostat, flushed radiator. It never tries to overheat unless I am at idle for over a couple of minutes after exteded driving. INSTANTLY DOWNLOAD a MerCruiser engine & sterndrive repair manual 1984 mercruiser 120 wiring diagram 1984 mercruiser 140 3. Never had any problems with the car running hot before this. INSTANTLY DOWNLOAD outboard repair manuals straight to your computer in seconds. 3 overheating problems 2003 mercruiser 4. 7 liter engines. 225 is not overheating. The electric fan will only come if i unplug the connector to the cts then it causes the engine to run rough. The elusive manifold vacuum leak. Hg (inches of mercury) or (kPa) to check this specification. Although they were sure this would help, they did the work. These forums were a lot of help, and read through most of the posts on overheating. 0 liter on a '95 Four Winns. Would appreciate help. whenever i have to idle for an extend period of time my 07 jetta while overheat but once i start driving agian it will go back to normal temp. 7 Mercruiser sterndrive raw water cooled. Swapped out the auto trans solenoids the other week and now the truck is overheating. I have doubled checked the seawater pump, changed the 3/4 hose between outdrive. Of course, you should never overlook the possibility that the water intake is plugged. 2 MPI actually weighs less than the 7. 7L V8) is overheating while idling or driving slowly in traffic. Easy to check. HelpAnother Hunting Idle Nightmare (Virgin PRC-J01 ECU) Jump to Latest Follow. Mercruiser overheating at high speed 1995 46 hp mercury outboard will idel but wont take throttle free suzuki 1973 6 hp outboard motor repair manual how much gear oil in 20hp johnson outboard 1982 yamaha 40hp trim solenoid wiring diagram ho use low mixture for jhonson 4hp 135 mercury outboard repair manuals 1993 yamaha 43 horse instructions runs hot 2004 80 hr mercury outboard runs starts but. Tell me a bit more about what's going on so the Marine Mechanic can help you best. 3rd Gen Ram Tech - Help!! 05 Ram 1500 Overheating at Idle - Searched the forums for an answer but didnt come up with much. The engine only over heats when on plane at higher RPMs. An electric fan will pull much more air at idle/slow speeds than the mechanical fan is able to do. overheating @ idle only Hey guys, I'm a diesel mechanic and don't know too much about these little cars, I have a doosey of a problem that's got all my buddies, the guys at Mazda and me completely stumped. Trouble at idle may point to a manifold vacuum leak. I've removed the dual-port strainer on top of the nozzle and it's fine. The temp gauge shows the engine is over heating but the heat coming from the engine contradicts the gauge reading (in my opinion) I am not sure of the regular engine operating temp for a 289 4V but I took some temperature measurements with an infrared temp gun and recorded the following. Re: Mercruiser 7. It was about 500 miles and my sedan (with 180k) was a champ. but i might just change the head gasket for the hell of it. The flow seemed a little weak but when I increased the rpm it increased. Warning signs & symptoms of overheating: Only after driving a short distance of travel, the engine starts knocking. Thats the short answer. Sounds like a fan problem. Engine overheating while sitting idle!! **FIXED** THX CA My engine is overheating after only 15-20 minutes of driving when I stop and let it sit idle for 5-10 minutes. Don't let your boat sit idle any longer than it has to. Start by checking to see how much coolant is in your system. then you can avoid all those lines running across the engine bay as well. Rough Idle When Starting Cold, Then Goes Away When Engine Is At Operating Temperature More Details Below I have an older, low mileage vehicle with a V8 engine. 7 problem with 496 mercruiser 8. When attempting to diagnose an overheating MerCruiser 5. One old guideline says that overheating at highway speed is a coolant flow problem, overheating at idle is an airflow problem. Use this instruction sheet when installing the above water pump impeller kit on 2009 and newer Evinrude E-TEC® 25 – 30 HP outboards. Remove it and stretch the spring by hand - make it a good inch longer. 0l won(39)t idle. That said, I'm wondering about the mechanic's diagnosis, overheating at idle could also be caused by reduced coolant circulation (perhaps due to a water pump with a badly eroded impeller) or by a lack of airflow over the radiator at idle which could be caused by a fan failure or by something blocking the radiator. So later that night the fan clutch was replaced because it seemed like it wasn't cooling at slow speeds or during idle. Some people think you're supposed to turn the idle mixture screws all the way in, and then back them out 2 1/2 turns. The elusive manifold vacuum leak. The most common problem with both two- and four-stroke engines begin with the fuel system. The temperature remained stable at 87-90 when bleeding and I went for a 20 minute drive and the temperature remained stable. Over 1,000,000 Visitors. mercruiser overheating at idle; This manual only. You already have a shroud. Most cases of overheating are caused by failed sea water intake pumps. Engine Overheating: Mercury Johnson Evinrude Yamaha Suzuki Mariner MerCruiser DOWNLOAD outboard or inboard marine repair manuals straight to your computer in seconds —fix your problems now. I bought it so late in the year (October 95), that I never had a nice weekend to get it in the water, but I got such a good deal I figureed I could wait. Yes overheat shows at idle on muffs lift to 1500 revs and temp falls back down. I also noticed that the idle was a little slow so I adjusted the carb so the rpm was between 800-900. In this article, we look at the common causes and solutions for engine overheating. If you have a stock distributor and know either the timing at idle or the maximum advance at a given engine speed and you have a good timing light, you will have no trouble setting timing. Remove it and stretch the spring by hand - make it a good inch longer. The eight cylinders fire in a 1-8-4-3-6-5-7-2 sequence. Overheating Mercruiser Alpha One Gen 1- Just in time to ruin 4th plans! briefly run motor at idle and 1500 rpm and view/measure the flows. Temp is normal if at 1000 or above. View online or download Mercruiser Sterndrive 5. 1 problems with 2005 6. Has about 350 hours. Under power above 1000rpm, it seems to run fine, but anything below that, it simply will not idle and sounds like its not running on all cylinders, almost like a misfire. Dodge Dakota Forum for Dodge Dakota trucks with an interactive site including Dodge Dakota Forums, Pictures, Links, Message Boards, and Chat Forum. I am having overheating issues as well, coupled with the fact that the cabin heat can also be wonky at the same time. Starts and runs great on land on the hose and then once on the water starts right up but after 10 min or so of low speed or at idle starts to run rough or stalls. One old guideline says that overheating at highway speed is a coolant flow problem, overheating at idle is an airflow problem. Oil pressure is usually 30+ at idle on 15w-40. 3 V6 overheating issues Eyebrows Gone. 2 mercruiser engine; how hot should a mercruiser iboard. The only parts that. Keep the engine at idle for a few minutes and let the engine oil do its job. When that spring gets compressed (less springy) over time, it leads to overheating at idle (only). I have an 89 mercruiser 5. Water should be visible at the top of the radiator. -gctid738981 05-29-2016, 09:07 AM So after clearing up some initial non-engine issues with our 2005 bayliner 195 classic, I'm now entering into the foray of those. You can also use a cheater to check the fan motor to see that the fan itself isn't the problem. That's when the truck began to overheat again, going all the way past the 3/4 mark. The dealer said it needed the heads reworked ($4500). Enable away mode and prevent // the sleep idle time-out. Cylinder heads and block checked out good at overhaul, but that still leaves manifolds as a possibility. 0-liter engines for sale. It would only get real hot on the long uphill grades on the mountains and start puking coolant from the overflow tank. That is the only time that it overheats - just at idle. hi thees cars are a nightmare for the coolent problem try bleeding it again might take 3 or 4 times before its got rid of all the air my cooper did. Brake drag increases the load on the engine and makes it heat up. Wide open throttle RPM range chart for Mercruiser powered boats. In the 6 years I've owned this boat, it has always run a little above 140*. Warning signs & symptoms of overheating: Only after driving a short distance of travel, the engine starts knocking. Re: D-jet M117 overheating at idle only « Reply #4 on: 31 August 2012, 07:37 PM » The flow issue sounds more like waterpump but the heating while stopped is either viscous coupling or electric fan or both. The Mercruiser has inspection ports on the font of the exhaust manifolds. Any good Fresh Water Cooling System should have excess cooling capacity. I'm forced to shut it off or it will start to boil the the coolant and cause damage. Forced idle RPM only All Serial Numbers 0M000000 and Above Models All Serial Numbers 0M000000 and Up 496 MAG BRAVO 496 MAG HO BRAVO (PCM 555). Troubleshooting starting and running problems can sometimes be quite difficult. my ski buddy's boat started overheating at slow or idle speeds last year. 3lx mercruiser, 205hp. If you start it and let it idle, it doesn't get hot. Overheating at idle. Pretty confident the impeller is working ok so i replaced the t-stat. My 05 Ram 1500 is running hot at idle, has given me the check guages light and beep. 0 mercruiser overheat at idle; can mercruiser overheat at idle due to old spark plugs and wires? engine surging at idle on a 5. Why Does My Car Overheat When Idling? by Paul Novak The cooling system of an automobile is a balanced combination of components working together to efficiently remove the heat from the engine and dissipate it into the air. 0 One of the most popular sterndrives on the planet The ideal propulsion choice for runabouts up to 19 feet. 4 multiport injection model has 310 propshaft hp and 231 propshaft kilowatts. Thats the short answer. You can test this by letting your car idle long enough for the engine to heat up. The electric fan will only come if i unplug the connector to the cts then it causes the engine to run rough. 225 is not overheating. 0 lb to 20lb if pressure from idle to 3500 rpm. This boat has. Hi all, Looking for the usual good advice. Remove the manifolds if they appear clogged. Check the pressure cap, too. Now overheating again. and wont stop untill we get underway for a bit. Over 1,000,000 Visitors. If the engine overheats a few minutes after start up, the most probable cause is a defective thermostat. First thing to check (playing the averages here) is that ball/spring setup. Am hoping I can offer some tips and get some advice. This boat has. It takes be about 5 minutes to get back to the dock at idle. 0 liter V8 engine, it's important to inspect both mechanical and cooling system components. For about 4 weeks now it's been this way. The thermostat is not a maintenance item and should only be replaced when it failsand you'll know when it does, as the temp gauge will not rise at all and you will have no heat. Higher RPM can overheat the engine. I swear I have been lurking on this forum for ever trying overheating issues, but only at idle - Page 2 - Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum. All other Saturns specify 2k rpm's. i put in a new waterpump new radiator, 160 degree tstat, 16lb cap and its still overheating. Overheating when driving, but not at idle ? Kind weird that it only overheats when driving it and I had it idling for Omer an hour am a half. one night i drove 10 miles or so and it over heated and lost all its water got to a petrol station filled it back up and it justed kept ****ing out wife came with 10 2 litre bottles full of water and every 1 mile had to keep topping up until we. Changed fan relays as well. After the engine gets up to normal operating temp, it'll be fine as long as I am driving forward, but after slowing down for a stop light, for example, the temp needle climbs. 4 mercruiser engine to overheat pre ignition in a mercruiser 4. but i ran motor out of lake with earmuffs and pump seems to be fine water is comming out of the holes with. The air coming out of the vent also goes from cold to warm. When the thermostat opens at operating temperature the overflow tank will bleed itself. If traffic is crawling, move up only when the gap between you and the vehicle in front of you gets too large. Sometime this condition will show up when the coolant level is low or if the thermostat is sticking and only working occasionally. If the overheat condition only exists when the boat is run at high speeds, the cause may be clogged exhaust manifolds or risers. I have a 79 Sea Ray with a 470 Mercruiser. If it only overheats at idle but not when rolling down the road, the thermostat isn't stuck closed. Pretty confident the impeller is working ok so i replaced the t-stat. How to Shift Your Boat. Mercruiser 260hp 5. Changed fan relays as well. Easy to check. 2 liter mercruiser stalls out at idle problems with mercruiser 4. My dads truck had a similar problem to yours. The cabin heater box is a large enough radiation area that it alone can suffice to prevent engine overheat, and there's no thermostat between the engine and the heater box.