# 2006 GTO Cooling Problem



## GoatDad (Apr 20, 2012)

OK, I know, but I did search the forums, at least 15 pages deep on three different topics and I didn't find any help... 

I am working on a 2006 GTO with LS2, Auto Trans, and about 60K miles on it.

It spikes to the red zone on the temp guage and starts mis-firing. (Is that limp mode?)

I looked it over, and found that the radiator was cool to the touch. 

I replaced the thermostat and temp sending unit, still got same symptoms. 

I replaced the water pump, now the temp guage still pegs and starts mis-firing, but now the passenger side of the radiator is hot and the driver side side is still cool to the touch. Fans come on after about 10 minutes of idling, shortly after temp needle pegs. I'm not getting any heat from the heater by the way...

I am now suspecting that I have a clogged radiator? I have never encountered a clogged radiator before, am I right? Can it be saved, or do I have to go for a new one? I called a local radiator shop, they said they can clean it out and pressure check it for $50 if I take it out and bring it in... That is my plan for tomorrow.

So, am I heading in the right direction? Please advise, I need this car running this weekend!

That said, I have fallen for this little Australian toy (this one is my son's car). I am going to get me one of my own very soon!

GoatDad


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## jetstang (Nov 5, 2008)

Welcome to the forum, nice intro Knute.. Buddy of mine, told him to ask question here.
Do you have to jack car up to bleed radiator? Overheats right away.. Or how to bleed rad? I have old, no new.:cheers
Guy told him it was clogged heater core, I said then the heat wouldn't work but it would still cool. Might of had a leak and rad is clogged with leak stop, explains clogged heater core. 
Maybe run some rad cleaner through it and see what is actually leaking, if they were actually covering a leak when they sold it.


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## GoatDad (Apr 20, 2012)

Thanks Dan... I'm looking for one of those $150 lifetime guarantee radiators right now... Know any good sites?


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## GoatDad (Apr 20, 2012)

Would you put a $115 radiator in your car?

Silla OE Replacement Radiator (New) - JCWhitney


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## jetstang (Nov 5, 2008)

Yeah, same as autozone I assume, and warrantied. Quality costs.. You probably need to flush and reflush, maybe you don't need a radiator, but need to find and repair the leak they are trying to fix. If it did overheat a few times from the PO, the motor may be hurt.


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## cutlass79500 (Jan 29, 2012)

Are the hoses getting hot?. Also did you do a sniffer test. I have ran into a few older gm cars that had a hairline crack in between the valves not leaking water into combustion chamber but pressurizing the cooling system. I hope thats not the case. I just bought an 06 with 36k i want to put a 180 t-stat in it did you have to bleed the system? You said you changed the thermostat. I have never worked on ls2 motors but worked at dealerships in the 80s and 90s i always drill a tiny hole in the lip of the thermostat that way any air that is trapped behind it can escape and you do not have an air pocket and the temp bulb on the t-stat is in water at all times. Good luck with it


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## GoatDad (Apr 20, 2012)

No sniffer test... Hoses were hot. I can't find any provision (bleeder screw?) or instructions anywhere for bleeding the system. My Impala has a bleeder screw right on top of the t-stat housing which is quite handy... No such animal on this LS2. I got a 165 degree t-stat for it. I used to drill those holes too, but this one has a small hole and the world's smallest check-valve in it, I suppose designed to let air seep out of the block... 

I pulled the radiator out today, and was going to go have it pressure checked and cleaned out, but I put some water to it and it seemed to flow through, but not at the rate I would have expected. Put the air to it and found a 4" long crack in the tank. Radiator shop dude said he could fix it, but not for less than the $135 radiator I ordered from JC Whitney today. It will be here Tuesday, and I will slap it all back together and see fi that fixed it. If not, I will be at a loss for what to do next...


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