Engine overheats after a long drive or when stuck at a traffic jam?

If the thermostat was closed it would boil over. If stuck open, you would have no heat. Wait till service to replace it.

This guide should help us fix it

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down this guide and report back.

My sister bought a used subaru and it is running hot.It doesnt have water in the oil.The radiator cao has been replaced by a mechanic and the coolant system was flushed.It doesnt have white smoke when starting up and running.Im at a loss,i dont know what else to check on this car.She is a single woman with a son and on a fixed income and needs this car very bad.Im tired ofseeingherbeing taken advantage of.She bought the car from a guy that said the heads had been replaced but this thing runs hot to the pint of her having to pull over to let it cool down.she is going by the tempguage and the electric fan works on the vehicle.please help me resolve this issue.Thanks for your response...

there are a lot of things this can be, first when it gets hot use a thermal temp gauge you can get pretty cheap and see if it iactually is running hot. then check thermostat. if the rad has been replaced the head gaskets may be on backwards. if you find out it'snot overheating then check gauge and sensor/sending unit.

In the last week I have had my coolant overheat. I can turn up my inside heat and it will blow cold air. However, if I turn off my car, let it sit for a few minutes, I can see the temp go down then it cools fine and I can drive with it in the appropriate cool zone. It sometimes hits the "red zone" on the idiot gauge but never blows a hose and I can smell the coolant once I get out, but I don't see any leaks. I know it's got a TON of mileage on it, at 277786 miles but with this economy, I'd like to make it last until spring if possible, or am I throwing good money after bad. I keep this car WELL maintained and I take care of any issues immediately. What can I tell my mechanic to check to make sure I catch this, or am I dreaming???
Thanks
Ginnydog

If you have lose heat, I would start with the thermostat. Also, you may want to consider having the system power flushed.

Let me know if it helps.

Joe

My subaru has been a great car - no repairs for 4 years! But finally I have started to have a problem with it overheating. It started on a hot day a few weeks ago using the A/C. Next it got hot going over a mountain pass but was fine coming down on the other side. Now it's getting hot driving in 90+ weather on the flat ground. I took it to a mechanic and he felt it was the radiator possibly. What about the thermostat? I got a radiator flush which did nothing to solve the problem. I turn on the heater before I let it get too hot but man, I'm starting to melt!

Hi there,

Get the thermostat changed, make sure that the cooling fans are coming on and the A/C condenser fan is working with the air on, have the radiator cleaned & flow tested by a radiator shop, just a back flush is not good enough as there may be a number of blocked core tubes still.

mark (mhpautos)

AKMT, did you resolve the overheating issue with your car? I have the same thing going on with my 2001 Forester (164000 mi.)

Thanks,
jfk63

Hey JFK63. Yes, after some trial and error I replaced the radiator and it instantly solved my problem. You might have your radiator tested to see if it's clogged. Good luck!

Engine Cooling problem
2000 Subaru Forester 4 cyl All Wheel Drive 165000 miles

I have a 2000 Subaru Forester that has been overheating. I replaced the headgasket, themostat, radiator cap, water pump. All hoses have been checked. The car is still overheating. The bottom radiator hose feels cool.???? If I remove the thermostat the car runs fine. I also replaced the fuses for the fans.

seems like may have a clog in system or bad heater core. suggest flushing cooling system. the bottom radiator hose should be cool that means radiator is doing its job..

My engine overheats when I run the A/C for about 20 min.
There are no smells, visible leaks, smoke or any other things I can see.

Goes back to normal when I turn off A/C

What's up with that

Have u checked if the fans are working properly?, both fans should start working a few mins after normal temp is reached; check fan relays too. Also, have u ever changed thermostat? At that millage u should have at least twice. If not, it might not be working properly. Have u ever flushed the radiator?, if not it could be clogged. Oil level and viscosity also play an important part. If u live on the desert or in moderately high temp area oil viscosity is very important to avoid "thinning" which can cause excessive wear and over heating. There are other things that can cause overheating, like bad engine timing, worn or stretched timing belt, and piston-to-cylinder clearance. In some cases the problem might also be as simple as checking the temperature sensor, if bad it might not be sending the signal to make the fans work. This last check is optional, but extremely important; check for low engine compression on the cylinders and check if the coolant level has dropped, but with no visible leaks (except in some severe cases where coolant is puked out the tank; the most noticeable), as these are signs of a blown out Head Gasket. This issue is also noticeable by checking the oil for whitish fluid; these happens when oil and water/coolant mix at engine running temperature, which by the way can cause severe wear or damage to all engine components. Foresters from the series 1997 -2002 tend to have this problem at high millage, but its still an great car, i just finished overhauling mine (full engine repair $800 doing it myself, had to change pistons, cut cam heads, and bore cylinders). Hopefully all of this will be helpful to you :D

Thanks for the info...
This will help me when I go to a mechanic, as I always feel that if I know a little bit about what might be wrong, then perhaps I might not get the runaround. When you are a woman you can see the snide looks, when you are a woman with white hair sometimes the guys actually look like they are laughing out loud.

I do love my little car...runs like a champ on all these back dirt roads.

Let me know if u need some shop manual help ;)

Over heats. Head gaskets leak. Externally. how to fix the problem. I am a mechanic. Any ideas and thoughts would be alot of help. Thank you.

Hi there,

you really only have one option, pull the heads and fix it properly, Subaru use a steel head gasket and the mating surfaced should be spotless, if they have the slightest mark they will leak again.

Mark (mhpautos)

I have a 98 subaru forester that pushes coolant from the radiator to the overflow. It does this in just a few miles. I keep it from overheating by putting the coolant back in the radiator from the overflow. I've tried bleeding the system many times, with bleeder on the radiator. I also put on a new radiator cap. Nothing helps. I'm going to replace the thermastat next but I don't think that will fix it. HELP HELP! If you have any ideas I'd really appreciate it. Thanks, Brian.

Ok I would take it to a shop that can to a chemical test on the radiator. What this will do is determine if there is compression getting into the radiator if so then you will need new head gaskets and maybe the heads shaved. Get back to me with what you find.

take the radiator to a radiator shop to have it rodded, the problem with suburu radiators is the flow tubes are so thin that they can get clogged very easily just a little caked up dirt will do it

i've replaced the water pump, timming belt, head gaskets, fans work, had checked heads ok. new thermostat. still overheating. any sugestion on this problem.

Radiator is it good if so maybe air lock in the system try bleeding it see below

Always bleed air from cooling system after replacing coolant. Set heater for maximum heat. Remove radiator cap. Loosen drain plug and remove drain bolt (if equipped) from engine block. Drain coolant reservoir. Fill coolant reservoir to MAX mark with 50/50 water-coolant mixture. Loosen bleed bolt and fill radiator up to base of filler neck. Close bleed bolt when coolant flows out without bubbles. Tighten bleed bolt. With radiator cap removed, start and operate engine to normal operating temperature. Add coolant if necessary and check for leaks.

1998 Forester no problems at idle or town driving but overheats when driven 20 to 30 min at freeway speed. I have replaced rad (was plugged), replaced timing belt and tennsioner (belt was loose tennsioner weak), replaced water pump and thermostat ( just hoping) nothing changed, when it gets hot heat inside car goes away and eventually starts to boil over. I have not checked head gaskets because there is no sign of trouble, no leaks, no smoke out exhaust, no missfire, engine runs very smooth. I have so much time invested in this job I don't want to give up but running out of ideas.Cooling fans work and are running when car heats up,and then starts to push out coolant. Hope sombody has seen this and give me some ideas. Thanks Mike
PS tired of looking at car with dumb look on my face and not doing anything about it so I just tested for head gasket leak NOTHING WRONG THERE EITHER HELP HELP HELP HELP HELP HELP

Have you checked / replaced the thermostat?
Good luck.
ps (How are the brakes do you have a
low peddle?

i've got the same problem. had heads check ok. mine has to much pressure in the coolent system. startes out low then goes passed 35psi. this is when the coolent comes out. need help too. new cap too.

must be head gaskets. have you had it tested with a gas analyzer to see if carbon monoxide is getting into cooling system?

I just had a new radiator and hoses installed. The tempreture is acting strangly now. The temp will be normal for awhile then quickly will rise into the red zone. By quickly I mean within 30 seconds. I pull over and shut the engine off for two minutes. WHen I restart, the temp is a little below the red zone. As I begin to get back onto a road and drive, the temp will quickly drop down to normal. Again by quickly I mean 30 seconds. How can the actual temp go up and then back down so fast? I had the theromstat replaced with no effect on this over heating issue. I think it might be a bad guage but it was working fine before I had the radaitor replaced. I don't want to assume that the guage is wrong and drive around without a working temp guage.

Has the thermostat been replaced with a genuine subaru part? This is a real common issue when aftermarket t-stats are used. You had also stated that other repairs were done as well. I think your main problem is the t-stat and that there is air still trapped in the cooling system.

My vehicle has been overheating off and on for about a month. I have drained and flushed the cooling system and installed an aftermarket thermostat. Then I installed an original Subaru thermostat then it ran well for a week. Then it started overheating and I was told to drill extra holes in thermostat and bleed air which I did. That made my vehicle run well for a week and now the temperature gauge needle will go to hot for a few seconds and back to normal and keep repeating. The engine does not seem to be overheating. Could this be a sensor or gauge problem or head gasket?

it may be a sensor problem or gauge. you will have to check if it is getting power to gauge as well as sender sending it. another problem may be a bad ground especially if you hit a bump and gauge goes either to hot or normal.check the grounds in picture as well as battery to body ground for corrosion or loose.

If you are wondering if your problem could be a blown head gasket here is a step by step guide on how to detect that problem.

https://www.2carpros.com/articles/head-gasket-blown-test

so i just bought a subaru forester and it has overheated twice in the past month. Both time I have been ideling and both time when I drove about 300 yards it immediatly went down to half way (which I assume is normal). The coolent level has remained the same and looks a little dirty. What say ye?

Cooling fans may not be comming on. Check to see if there on at idle with engine at operating temp. If not check relay and temp sender.
Good luck

how do you check the temp sensor and relay?