Guest HALLOWEEN Z Posted September 29, 2010 Share Posted September 29, 2010 I've been having a problem with my car for some time now. A good while back the transmission went out and when driving home in reverse it overheated. During the engine pull to take tranny out the radiator got damaged so I replaced it with a different gm radiator. Well since I got it running i've been having these temperature fluctuation problems. It's ok at idle but driving down the road it goes up and down untill it gets to 210 and it starts to climb so I shut it down. I've got a 180 degree thermostat but I've tried 160 before and it doesn't matter. I've been told that I have air in the system but I don't think that is it. I warm it up and there is no more air coming out of the radiator, I also have an overflow tank. I've tried jacking up the front of the car also. BTW I have since switched radiators to a datsun style 3 core radiator didn't change a thing. I have no heater core or anything so it shouldn't be hard to get the air out!! I even invested in one of those summit water necks with the cap on top because the water neck is close to even with the radiator fill cap. I've tried drilling a couple holes in the thermostat so air could bypass it. I have no other signs of blown headgasket. Nothing funny in the water or oil and not smoking coolant. I've done a compression test and everything checks out. Any other advice I think the water pump is fine it sure pumps out the water good when the water neck cap is off. Could it be a cracked head, block, or gasket? I'm going crazy Quote Link to comment Share on other sites More sharing options...
RS Speed Posted September 29, 2010 Share Posted September 29, 2010 (edited) possible pinhole head gasket leak causing exhaust gas to get into coolant system... doesn't always show up as coolant in oil when the gasket goes. You could use a radiator test kit which checks for exhaust gasses in the cooling system to rule it out. Edited September 29, 2010 by RS Speed Quote Link to comment Share on other sites More sharing options...
Guest HALLOWEEN Z Posted September 30, 2010 Share Posted September 30, 2010 I was thinking this maybe but thought i would see bubbles at idle after the car started to warm up with the cap off. But I guess if it was a pinhole then when I drove it wouldn't be noticeable until the extra pressure caused by the load. Quote Link to comment Share on other sites More sharing options...
hoov100 Posted September 30, 2010 Share Posted September 30, 2010 When you bleed the coolant system be sure to put your hand over the neck of the radiator and move the hoses around and squeeze them to push the air out. Quote Link to comment Share on other sites More sharing options...
Guest HALLOWEEN Z Posted October 2, 2010 Share Posted October 2, 2010 I've almost got the heads off, started after work today. Looking in the water coolant in the cylinder I'd say I had a blown headgasket. Brown and black crud built up more than in other motors I've broken down. Not just rust. I'm gettin the heads checked out next week and I think I'm going to go ahead and put these heads on another motor with very low miles since rebuild. It has flat top pistons and the heads haven't been cut down. I think I've heard around 10:1 compression with this not sure which thickness of head gasket. But these flat tops do have the valve reliefs. Would it even be worth it power wise? I figure I might as well do it since I'm removing the heads it would take a little bit of time but not to long to swap the block. Both have about the same mileage. Ofcourse I don't know if there is any engine damage on this block I have in now. Quote Link to comment Share on other sites More sharing options...
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