Car has been running hot lately. Has a new radiator, air dam is intact, fan works (manually w/ toggle switch). I need To keep the fan on and the heat on to not overheat even on the highway. Even at that it is still pretty hot, between 230 and 260. No oil in coolant and vice versa, coolant level is good and circulates through radiator. Thermostat is a year old and I can feel coolant traveling through the hoses when running.

Only thing ive noticed is after about 5 minutes of running with the radiator cap off, the coolant (mostly water) fizzes up and looks like sprite. ddoes that mean anything bad or is it normal?

 

Bump

 

Maybe you're not circulating enough coolant? It's tough to say with something like this. Are you losing any coolant? Do you hear/see it bubbling out into the overflow reservoir? How's your radiator cap? Does it hold the necessary 16 psi? If you put the engine together yourself, it could be a gasket failure, though those usually show something else more indicative. Check the easy stuff first (which you seem to have mostly checked already). One last question, have you done any maintenance recently involving the cooling system?

 

forgot to mention I have a new cap on the radiator as well. The only "maintenance" ive done is adding water when it first was getting hot. I cant see a leak anywhere and no steam coming out exhaust. No puddles under the car but I am losing coolant slowly somewhere.

I did notice today I can squeeze upper and lower hoses easily, and can feel the coolant moving through the hoses, both of which are new. Should I be feeling a good amount of pressure through there? I have no idea about the water pump. The engine supposedly has 90k on it, I swapped it in a year ago with 85k claimed miles and have had no problems until now. Could the water pump just be shot?

 

Typically you wouldn't see much flow if the water pump went out. That "fizzing" you're mentioning makes me think it's boiling somewhere, or getting some air pumped into it. If you want to take off the water pump, that would be a good start to taking off the heads if it comes down to that. If that pump is fine, I would say your head gasket is the culprit. The next time your car has been sitting for a bit, loosen the drain plug on the oil pan and see if you get any milky looking oil to come out. You might not have enough of a leak to make it noticeable on the dipstick.

Oh, and as far as pressure goes, you shouldn't notice much. 16 psi isn't a whole lot.

 

The radiator hoses supposed to be rock hard once coolant starts circulating! When engine is cold you should see (cap removed) some coolant circulating through heater bypass port into the radiator. Also, since you've swapped engines be aware that some water pumps are configured for reverse rotation - serpentine belt setup vs. conventional V-belt setup. But before jumping to any conclusions I would check thermostat - stuck closed would cause hot temperature. A bad temperature sensor could be driving you nuts as well!

//RF

 

Ugh.. Thanks for the responses. I figured it was one of the gaskets, I just really was hoping not lol. how much pressure is "not much?" I have to squeeze the hoses completely together to feel anything circulating for wjat its worth. The exact same time this happened, my transmission stated shifting like the tv cable is out of whack but its fine. Any chance they are related or did I roll the bad luck camaro dice last week

 

Also check lower radiator hose for the spring inside, It could be collapsing. I've seen that before.

 

I checked my radiator hose today and it never felt solid even at 200*F with a 180*F thermostat. Maybe that has something to do with it being a 87 and later block and thus the different water pump? I'm not sure. Like RF said though, I would look into that water pump change. I believe it happened when GM changed to a serpentine belt setup. What did the engine come from? And did you use your accessory setup from the 91 or from the engine you swapped in? Still, if it ran for some time like it is and NOW you're having issues, it makes me think something has failed.

 

I struggled with this kind of overheating problem for a long time. In the end I couldn't drive it without boiling through the overflow tank. It was a head gasket.

 

Those were my thoughts as well. The engine is claimed to be an L69, but the guy also said it came from an 84 el camino. I dont believe those ever had the H.O but the base timing the engine likes and perceived harder pulls over my old l03 make me think it may be but I can't see the casting number well enough to confirm. Anyway, assuming it is from 84 I'd imagine it was not serpentine, and I did use the serp setup from the L03. Wrong water pump may be it. I'm also changing the coolant temp sender. I was gauge watching earlier and caught the neefle jump from 180 to over 220 in an instant. Maybe it's just the gauge since I dont have any symptoms of a gasket leak but the gauge saying it's getting hot? And the slow coolant leak is water dripping out of the weephole of a failed water pump?

 

Interesting. My IROC is a 5.0 Liter HO clone, which should have an L69 engine. In fact, it's an LG4 with a cam and had .015 copper head gaskets and no flat top pistons. I guess the double snorkel air cleaner didn't really make it an L69. But it did run 14's.

 

Bubbles in the rad after the stat opens is one tip.Leakdown tests will help pin point the leak.Likely head gasket issue.