I have a 2003 Subaru Forester with the 2.5 just
bought it and did timing belt plugs wires and coil.
Ran great for about a month then started
overheating so I put a new thermostat in made it to
work and back twice and overheated again. I
pressure tested the cooling system checked out
good, compression tested the cylinders they were
fine. I check the fluid several times and bled the
system with the cap off and it still intermittent
overheats and backs up into the overflow reservoir.
Any thoughts before I start throwing parts into it like
a water pump? Any help is greatly appreciated
Did you flush the system out? You may have leaking head gaskets so look for bubbles in the radiator. If the radiator is really dirty it may be time for a new one. BTW the water pump is inside the timing belt cover so you would want to do the timing belt and idler wheels while you are at it. You can get the entire kit for around $200.
I checked compression it was good and it runs fine doesn't smoke and I already did the timing belt about a month ago I'm going to flush the system tomorrow and get a new rad cap before I replace the water pump
Here's the funnel I bought a few months ago. Have yet to use it but I know they're quality. There's another guy on here that bought one and loved it. www.amazon.com/Lisle-24680-Spill-Free- Funnel/dp/B00A6AS6LY/ref=sr_1_2
Whatever you do.. DO NOT run that car hot!! Purge / bleed / burp that system - sounds like air is trapped. You don't have to have the funnel if you need to do this now. Keep us posted and I hope it works out.
Ok tried flushing the system with that blue devil stuff and tried burping all the air out and replaced the rad cap but still overheating
hmm.. that stinks man. You should look through TheSubaruGuruBoston 's answers and see what he has said in the past about overheating. He may answer here after some time. I feel like something is missing and I'm not about to gander at what it is and waste your time. If your system is truly getting burped and bled right and you're still overheating, you might have a head gasket issue. You could try one more time on the burping if you park on a pretty significant hill, front up, and let it idle out the air. It might be enough to free any air from the tstat or if it's trapped in the block somewhere. But overall, I don't want to see you throw parts at any car. Maybe with more info / better direction (for me) I can be of more help but I just don't want to go in the wrong direction or "throw" scenarios at you. In the meantime, here's a good article I've shared with folks in the past that's a great read: https://allwheeldriveauto.com/subaru-head- gaskets-problems-explained-part-ii/
Ya I let it run for like a half hour with the cap off while burping it and never stopped bubbling I finally put the cap on and it started bubbling in the overflow reservoir. Which sounds like head gasket but I've never seen one leak only into the cylinders and not outside the motor. Plus I checked compression and it was perfect I would expect the compression to be low with a bad head gasket. Would a bad water pump cause it? I might just do it they are only $20
Keep trying.. If all is well (engine/compression/etc) like you say it is, it might be airlock in your heater core in the dash: https://www.cargurus.com/Cars/Discussion-t17159_ds614293
Well my buddy came over today and we did a block test in the radiator to test for exhaust gasses in the coolant, and there was, so head gasket it is. First one I've seen leek into the cylinders only and not externally. Thanks for the help
Sorry to hear that. I was rooting for trapped air!! Hey when you did your timing belt, did you replace the gears and tensioner, too?
Nope just belt
Right. You might consider replacing them if you tear into it. Rockauto has complete timing belt kits (gates preferred) for like 110 + shipping. And if you get the full gasket set, get the pricier option on rockauto.
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