High temps/possible overheating after water pump

[suba]

Car: 90 Legacy L, 5spd, 4wd, no A/C no ABS

Quick background:

Water pump indicated imminent failure, changed it out along with thermostat, tensioner pulley and idler pulley (cogged one). All parts came from the dealer, went easily, filled with coolant, started right up and ran fine, no leaks.

I did the pump because I had to go to a wedding and on an 800 mile trip this weekend didn't have a chance to take it for a long drive before hand but everything seemed fine.

Flash forward to today, driving toward Seattle I noticed that on hills the temps seemed to move just a touch above horizontal on the gauge. Cruising along the temps were normal, just below horizontal. Outside temperature was about 85 degrees.

Then we had to stop in traffic for a while and the temps climbed in to the red, couldn't stop so had to drive for a while like that with the temp moving in and out of the red zone. Engine ran fine, didn't seem too hot, fan came on normally, gauge just showed constant hot temps. Now the engine runs fine, idles and the temp shows normal, though I did notice a squeaking sound when I first start off (could be completely unrelated).

Any thoughts? Air pockets screwing with the gauge? I'm in a bit of a bind sitting here in Olympia with no tools or manuals. Any ideas would be great.

[macipusy]

Has the car ever overheated before you did the waterpump? Headgaskets have a tendency to fail if you overheat the motor.

Air in the coolant system could cause random overheating as well.

[suba]

I've never had a problem before, temps always stayed solidly just below horizontal on the gauge. I've ruled out the thermostat since on the highway the temps are normal, fan comes on so that seems to be a non issue. My only thought at this point is if I didn't get all the air out that air could be collecting in the system at low rpm and either slowing coolant flow or messing with the sensor reading. Has anyone else had a problem with air bubbles in the system?

[IronMonkeyL255]

I would guess air pockets, myself.

[suba]

That seems most likely at this point. I thought I had burped the system completely but evidently not, hopefully my head gaskets survived. I was able to pick up some coolant this morning, it was a bit low when I went and checked it so we'll try it again I suppose. When you burp the system do you typically do it running or off? I know with my 4runner it usually works best to park on an incline with the rad cap off and run the engine until it is up to temp.

[Legacy777]

Did you remove the bleeder screw on the top passenger side of the radiator? If not, that has to be removed during filling to ensure all the air is removed.

Fill with coolant with engine off, then start and fill as necessary. Make sure the expansion tank has coolant in it, so the system can pull it in if needed.

[AWD_addict]

Maybe you need more water and less antifreeze in the system.

[suba]

It's a 50/50 mix so coolant shouldn't be an issue. Less trouble yesterday on the drive down to hoodriver. On the highway or really moving at all the temps are normal, when stopped for any long periods of time the temps start to come up a bit. At this point I suspect an air bubble in/around the thermostat that is forming and keeping the thermostat from opening when at low rpm. I did find a nice steep hill to park the car on last night in hood river so we'll see if that got any more air out of the system.

[suba]

Burping it again on an incline didn't help, but I'm back home now so tomorrow its going in to the dealer to let them get the damn bubbles out. Oh well, doesn't seem like any engine damage occurred so now it's just an annoyance.

[suba]

Problem solved, sort of. There are combustion gases in the coolant, looks like I have a bit of a head gasket leak. The leak is putting bubbles into the system and over time causing the temps to climb. I hadn't noticed up till now because around town there wasn't enough being put in to the system to build up and cause a problem, but after driving for long periods it is enough to notice.

[tturnpaw]

And yet everybody on usmb says that the 2.2 gaskets are indestructible and should never have to be changed.

[evolutionmovement]

This failure mode seems to be the most common one. Certainly they're better than 2.5's but they do go bad.