Lumina Overheating

[baktrak]

I'm going to try to explain the best I can. Car is a 97 lumina with a 3100. I can let the car warm up in the driveway for 20 or 30+ minutes and it never overheats, gets warm but normal temp. Start driving and within 5 miles heat goes from warm to cold in a matter of seconds and the temp gauge rises almost instantly to almost red line. At this point the overflow is now full of coolant and overflowing. I can bring it back home and add more coolant and it acts normal again while idling in the driveway, but if you drive it the pattern repeats itself. The coolant will not return from the overflow if the car is being driven.

Absolutely no coolant in the oil/ transmission fluid or vice versa. System holds a steady 15 psi and I'm not leaking coolant anywhere but the overflow.

I replaced the head/ intake gaskets in october of 2012 along with the water pump. I used victor reinz gaskets. The water pump seems to have good flow. I put a new radiator in it last weekend as it was leaking a little from the tank. New cap and thermostat as well. I have verified that the thermostat opens correctly. The cap holds 14.5 psi, and the seal is clean.

I'm at a loss

[1988GTU]

Cracked head? Do compression leak down test and look for bubbles in the overflow.

[Maple Leaf]

Sounds like you got air in the system.

I've got a 98 and it was also hard to bleed the air from the system even with the bleeder valves.

Might have to do it a couple times.

Hope this helps!

[caffeine]

Ditto sounds like an air lock. Do a coolant flush.

[baktrak]

It is a cracked head allowing exhaust into the coolant, but not allowing a coolant leak. did a chemical block test and had exhaust gases in the radiator, but was not losing cooling pressures. I pulled the head and you can see the crack plain as day. I have a set of heads and intakes off of an 04 3400 that are going to replace the crappy 3100 small port junk.

[1988GTU]

Sucks but at least it wasn't washing the bearings with coolant .