HELP! 2004 SS overheating
 

guys...I need a hand. My 2004 is overheating and I cannot tell why. Through a process of elimination have replaced the following. 90 degree heater hose by pass fittings (leaking), lower rad hose (leaking), flushed the system 4x, replaced t stat, replaced water pump..no help...it's as if I've done nothing and am more than a little frustrated. Any ideas?:confused:

You might want to check your thermostat out, sometimes they go out, just pull it out and put it into a pot of hot water along with a thermometer and heat up the water till it opens up and take note of the temp that it opens. Other than that it might be your water pump(hopefully not becasue they really look like a bitch to change out.

is coolant looking? could have a gasket issue if it is leaking

dont even waste your time doing that, they are like 7 to 10 bucks just go get a new one

well, I'm going to check the thermostat as suggested, but it is brand new...could just be bad...as I said, I already replaced it, the water pump, the 90 degree heater by pass elbows, and the lower rad hose....these were all leaks that were visible...one things for sure, I got a handle on taking it apart and putting it back together now thats for sure:(

Does the car overheat when sitting at idle, at speed or all of the above? After doing all that work did you 'burp' the system?

yeah, it just over heats at idle. Today, upon completion of the water pump project I let it run, while in park, and it got up towards 220 quick, 10 or 15 mins at least, so I shut it back down...didn't even back it out of the drive way unfortunately, and yeah...I "burped" the system at the bleeder on top of the t-stat housing...

Sounds like you know your stuff and you have taken care of a lot of the usual suspects. Do the fans come on?

is it flowing properly? see if you get heat through your vents. and did you flush it forward, backward and forward to unlodge anything stuck? also was going to ask about fans but silver beat me to it

reverse flush....never heard of it? how does one go about this? and as far as the fans, they appear to be working properly, that is to say they come on when the temp is about 1/2 way..way before it gets to critical, but it is of no use...the engine gets hot enough to fry eggs on!! I tell ya guys, I've about narrowed it down to the radiator being blocked at this point as there isn't much more of the cooling system left to replace...blah! n

oh, and while I let it get up to operating temp, I have also been running the heat at full blast and it bakes in the car, the heat is most definitely blowing in the cabin..

hmmm, i was always told you flush it the direction of coolant flow. with water or coolant, whichever preferred... and of course its considered hazardous waste afterward. then you would hook it up and flush it the opposite way of normal flow to unlodge anything that settles in the direction of flow and then flush once more the normal direction. try flushing the radiator like that and see if it helps

Do you know if the t-stat opens? A simple way to check is feeling the radiator hoses. Grab a hold of the in-flow hose and feel for it to go from cool to hot. When this happens you know the t-stat is good because it opened up and allowed cooler coolant in to circulait around the block. I wonder if the t-stat is bad or you have a severe clog. You said the water pump, t-stat, elbows, were all good and no leaks. I also assume you are not losing any coolant.

I would get a pressure test done. If you do that you can test your head gasket. Another way to check the T-stat is to take it off and put it in boiling water to see if it opens.

Could be the head gasket or LIM gasket. Also, did you make sure the gasket on your t-stat was seated nice? I know mine was fairly difficult to get it on there good.

To check for a plugged radiator. Place your hand on one side of the radiator and then the other. If one side is cool and the other warm, then the radiator is plugged. I was also thinking a head gasket problem. You can test that by doing a compression check. If two cylinders next to each other have way low compression, then the head gasket would be faulty. I would check the radiator first, though.

well it's definitely not the t-stat, opens up fine at 195. felt the rad and one side is indeed cooler than the other....I'm thinking that's the prob and will be changing it out this weekend...

try to flush it forward backward then forward again to see if that helps first. if it dont. then replace! goodluck