27 replies to this topic

[BoostedS70]

did you change the thermostat. sounds to me like the thermostat is getting stuck and its not opening. i would change it no matter wat. its like 30$ from volvo vs a 500$ + head gasket job. I would also only use a volvo thermostat. another place to check would be the expansion tank cap if its leaking it will cause overheat because it prevents the cooling system from building pressure. overheating these cars is almost certain headgasket damage i see it almost everyday at my shop.

[Col.Kalashnikov]

Thermostat has been changed three times. Different temperatures and brands. Coolant has been changed, mixture changes. Checked and changed fan relay, fixed "sketchy" fan wiring. Waterpump was changed last year, I used a URO and changed bolts/gasket with it. I peeked under the timing belt cover, it doesnt appear to be leaking. Water Wetter added, rad changed. I have massaged the hoses to make sure everything is free of air. I will inspect the cap and change, I think I have an extra kicking around somewhere. Either way this is driving me nuts, and I need to hold out a little longer until the "new" motor goes in. I have used a GMB waterpump on the new motor. The engine is tired and I just want to limp it by for a couple more months but I'm going a bit OCD about the temperature. Like i said before the car has ALWAYS run slightly warm, now its just slightly warmer, but does not go above what its at. I know the risks of driving an aluminum motor warmer than normal, however I don't really have a choice at this point, and its coming out anyway. I think I may also change the coolant temperature sensor.

A volvo thermostat has been in the car. This made things worse.

[lookforjoe]

What specific T/stats did you use? Many do not have the proper vent/bleed & cheap ones don't regulate as well

I would suggest the SuperStant 45378 - it's a 180ºF t/stat - 10ºF lower than the standard. The "super' series work better than the standard, only a couple of dollars more.

[BoostedS70]

You shouldnt have used gmb water pump. Gmb and hepu are garbage I see them leaking from the frezze plugs on the pump after 30000 or so miles. Aisin are the best and are the oem manufacture for volvo. I'm sry to say this man but I'm pretty sure you have a blown headgasket I had a c70 the other day same problem got hot on the highyway coolant was dissapering. They overheated the car 1 time on the highway we changed everything. Rad cap t-stat sensors bottle everything didn't help still got hot . Boss said it was head gasket did the head gasket worked fine. It's not like classic head gasket were u see cloud of white smoke just got hot. And lost coolant. U can nurse it along for a while thow. If u got a new motor goin in just nurse it along till then.

[Col.Kalashnikov]

Its not losing coolant.

And the current pump isn't even GMB its URO. Sounds to me like you aren't reading everything.

[BoostedS70]

I was refering to the pump on ur new motor lol. Aisin is the only way to go man all these aftermarket pumps leak at the freeze plug. Ok so its not losing coolant change the tempature sensor its gota be somthin really dumb that's gettin missed lol

[Col.Kalashnikov]

Changed the coolant temperature sensor, stuff seems to be okay, measured with Laser thermometer. Car was never overheating. Also the pump I pulled off was Aisin, appeared to be leaking from freeze plug.

[dublin14]

Dont bother if you dont give a shite about the motor. As you said its a tired old motor. Keep drivin it and lookin forward to building and playing with your new motor. Then you'll find out what being OCD is all about lol