my baby keeps over heating... help!

[cristykay07]

so my 4th gen 2000 is a V6 automatic... laugh if you want i don't care...

and i keep checking the antifreeze and it's brown and gunky... i go in and get it flushed and guess what a week later... the same thing happens...and now it over heats. ugh!

has anyone had this happen before? idk if oil is leaking in somehow... or what the deal is... there's no crack in the radiator no fluids on the ground... and it doesn't over heat if the car is just sitting there running it's only when it's been on the road a few miles... literally with in 5 miles it will over heat... i'm terrified to move it incase something blows or cracks...

help me fix my baby!

[ron10]

your thermostat may be stuck.

[cristykay07]

well that could be the case although when it over heats and i turn it off to the car to cool down the electric fan is still running to cool it down...

[White_Knuckle_Tight]

Define flushed. like just water run through it or cleaner? Cleaner is usually never needed unless a problem like your occurs and your system's all gunky and discolored. Cause if it is just water, then it's not coming clean I assure you.
But as far as what else to do...start with the basics. Make sure your hoses haven't collapsed, go ahead and change the stat for the hell of it. They're cheap, what could it hurt.

[cristykay07]

the dealership "flushed" it and the antifreeze was green like it should be for about a week then just boom brown gunk....

[98_Camaro]

There might be oil leaking into it.
I know this was a concern with my '98 when we first got it since there was brown sludge in the coolant, and it's not an easy or cheap fix. Unfortunately, I can't remember exactly what caused it...

[Dave Coyle]

You more than likely have an intake or head gasket that is giving you the problem. Most of the time antifreeze will get into the oil instead of oil in the antifreeze when this happens but I have incountered oil in the antifreeze from both, once each. Keep an eye on your oil, if antifreeze starts to get in there you will have bigger problems.

[cristykay07]

awsome...

the oil looks fine it's not milky or anything...

it's just the antifreeze i got a water pump and more antifreeze... i think i'm gonna have to get new hoses... that's gonna be really fun to fix...

how am i supposed to know if i blew a head gasket?

[SSMickey]

The fact that it overheats going down the road but not sitting still sounds like a head gasket problem. When the engine is under a load, the cylinder pressure is increased and lets combustion gases into the coolong system. Have a good Tech take a look at it. There are several tests that can be performed to verify or rule out a head gasket problem. A check for combustion gases in the coolant with a exhaust gas anilizer is the most difinitive.

[cristykay07]

oh lord. getting a head gasket fixed isn't gonna be cheap.

[ninety6]

brown and gunky = GM DEXCOOL. It doesn't always last 100,000 miles like its supposed to. I had this exact problem, but without the overheating. if i had left it alone, it would have gotten there. (of course, i had the problem in the winter... and fixed it in the spring...)

in my 96 v6 i lost my heat, and ended up having to replace the heater core, and then when that didn't work i had to get a new radiator and heater core (again).

this was after getting a chemical flush twice i think. Your flush is cleaning out all the loose gunk, but there is probably still a ton sitting in your heater core and the bottom of your radiator.

oh, and i'd recommend a universal coolant upon replacing your radiator/heater core. GM dexcool likes to turn brown and gunky, as you have discovered.

pretty easy to do, the heater core is under the dash on the passenger side (take of bottom access panel), and the radiator is pretty simple as well. Just do a good flushing of the tubes while your radiator and heater core are out, but you have to pull the heater core tubes back through the firewall or you'll soak/stain your carpet!

picture of the gunky? i can verify it looks like mine....

[ninety6]

oh, and as far as overheating only when driving -- it could be that there is just enough "free" coolant to keep it cool from the lower operating temps of setting at idle. just a thought?

[02 WS6 TA]

Originally Posted by ninety6

brown and gunky = GM DEXCOOL. It doesn't always last 100,000 miles like its supposed to. I had this exacty problem, but without the overheating. if i had left it alone, it would have gotten there.

in my 96 v6 i lost my heat, and ended up having to replace the heater core, and then when that didn't work i had to get a new radiator and heater core (again).

this was after getting a chemical flush twice i think. Your flush is cleaning out all the loose gunk, but there is probably still a ton sitting in your heater core and the bottom of your radiator.

oh, and i'd recommend a universal coolant upon replacing your radiator/heater core. GM dexcool likes to turn brown and gunky, as you have discovered.

pretty easy to do, the heater core is under the dash on the passenger side (take of bottom access panel), and the radiator is pretty simple as well. Just do a good flushing of the tubes while your radiator and heater core are out, but you have to pull the heater core tubes back through the firewall or you'll soak/stain your carpet!

picture of the gunky? i can verify it looks like mine....

More or less, what he said. Bugdet for either a new radiator, or if you have a reputable radiator shop they can disassemble it, clean, and reassemble. There ain't a flush on the planet that will get the crap out of a gunked Dexcool radiator.

[ninety6]

Originally Posted by 02 WS6 TA

There ain't a flush on the planet that will get the crap out of a gunked Dexcool radiator.

not to mention -- i believe it actually starts to destroy the inside of the radiator. the gunk is rust. from the radiator fins. so even if you CAN clean it, it's probably gonna happen again.

I new radiator isn't too much... keep us posted!

i looked for a pic of my gunk.... don't seem to have one... i guess that was back before i took pictures of everything. ha.