weird overheating issue after new head gasket

[chucktile]

Has there ever been any type of sealant used in the engine? Are the heater hoses behind the engine hooked up properly; in to the in and out to the out?

 

It sounds to me as if there is a blockage somewhere in the cooling system. Maybe not completely blocked but just a restriction that traps an air bubble at times like when trying to burp. That quite possibly could be very difficult to locate/remedy:( I have never used a coolant flush machine myself, but I think they pump the coolant in thereby push air out. Maybe someone with experience in that area could chime in here. I could be way off base but it seems logical. Is the bottom radiator hose getting hot or does it stay cold and soft? For that matter, does the top hose get stiff as if pressure is building?

Edited May 30, 2012 by chucktile

[dm88]

It sounds to me as if there is a blockage somewhere in the cooling system. Maybe not completely blocked but just a restriction that traps an air bubble at times like when trying to burp. That quite possibly could be very difficult to locate/remedy:( I have never used a coolant flush machine myself, but I think they pump the coolant in thereby push air out. Maybe someone with experience in that area could chime in here. I could be way off base but it seems logical. Is the bottom radiator hose getting hot or does it stay cold and soft? For that matter, does the top hose get stiff as if pressure is building?

 

Finally for some more time to figure this thing out. It seems like I can't get the last of the air out. I even drained it and started over but I still hear the bubbling behind the dash and its still overheating

[chucktile]

I wonder if it is possible for the heater core to be causing this. Do a search for "heater core" and read some of the replies. I just did, lots of good info there. Let me know how you make out.

[Fairtax4me]

I replaced both with felpro. I didn't have them milled but I checked to see if they were warped. I used degreaser for the surfaces.

Even if there was so me gas getting into the coolant why would it go 30 miles fine then overheat on the off ramp?

 

Honestly, that sounds like a typical symptom of a failed head gasket on these.

 

Radiator cap new? OE Subaru thermostat new?

When you're filling the coolant, do you open the bleeder valve on the passenger side top of the radiator? It's just a plastic screw with a + on it.

 

What I do is remove the upper hose from the radiator, fill the engine with coolant first, reattach the hose and then fill the radiator. Fill until it comes out of the bleed valve, close that then start the engine and let it warm up. Top off coolant as it gets low until the thermostat opens. Put the radiator cap on, fill the reservoir a little above the MAX line. Shut the engine off just after it reaches normal operating temp. Let it cool, top off the coolant before starting. I do that every time, practically every car I've ever drained the coolant from, and have never had trouble with overheating after.

 

If that method doesn't stop the overheating you have bigger problems, such as a bad head gasket. Leakdown test or a block test (combustion gas test of the coolant) can confirm bad HG.

[Ricearu]

sounds like the radiator is plugged. the water pump will NOT Pressurize water but the faster it spins, the faster it moves water. if only some of your radiator is flowing, it could be that it IS enough to cool it while you are moving. Borrow a digial temp gun and check the radiator for hot/cold spots AS it warms up in your driveway. My legacy with bad hg did the exact same thing. I could drive it to work and back and be fine, but let it idle for 2 minutes at the mail box and BOOM, overheat.

[mdjdc]

I hate to be the bearer of bad news, but it is most likely a failure of the HG again. These engines are VERY particular as to the type of HG used. The ONLY gasket to use is a Subaru HG. I have used (and others too) non-subaru gaskets only to have them fail in short order. I did one engine and the gaskets failed in less than 20 miles. That was a situation where I bought four sets of "certified" OEM gaskets, but not Subaru and all four sets failed. What a pain, but a useful lesson. I will never used another brand of HG on a subaru. Felpro has a great name, but others have had them fail too. I think you are going to have to redo the HGs in order to be able to drive the car reliably.

 

Good Luck.

[ccrinc]

I hate to be the bearer of bad news, but it is most likely a failure of the HG again. These engines are VERY particular as to the type of HG used. The ONLY gasket to use is a Subaru HG. I have used (and others too) non-subaru gaskets only to have them fail in short order. I did one engine and the gaskets failed in less than 20 miles. That was a situation where I bought four sets of "certified" OEM gaskets, but not Subaru and all four sets failed. What a pain, but a useful lesson. I will never used another brand of HG on a subaru. Felpro has a great name, but others have had them fail too. I think you are going to have to redo the HGs in order to be able to drive the car reliably.

 

Good Luck.

 

+ 1.

 

Also, remember that these engines are primarily aluminum. Every time they overheat, even briefly, additional warpage occurs loosening the head gaskets even more. Everything has to be right the first time, there is no cutting corners on a Subaru. Done right, they are amazingly reliable.

 

Do or do not: there is no trying./Yoda

[davebugs]

I hadn't posted in this thread because it seemed the OP was in denial.

 

Glad to see I'm not the only one.

 

I think you get to redo the HG job (properly this time) and hope the rod bearings won't die shortly.

 

Or 2.2 it.

[mdjdc]

Yeah, Dave, he does seem to be looking for anything to do but listen to the posters telling him what to look for. Hope he fixes it before it is too late.