iMpoSStoR

well i've been doing some reading but have yet stumbled upon someone with the same problem.. the car (2006 GTO) will overheat after drive around the block then idling.. if i start the car and let it idle it will reach 208 which is when the fans turn on and fall to 196 which is the turn off point.. once i drive the car and temp goes over 208 it will not go down and start overheating. the motor is a 408, stock ported heads and intake with a d1sc procharger..i've already changed the thermostat, radiator, water pump, head gaskets, and added a fan(pusher) infront of radiator... any information will be greatly appreaciated.

davidws6

iTrader: (36)

You sure the head gaskets are sealing good? Might be pushing the water out?

What has changed when this started happening? Or have you noticed anything different in the way it runs?

Pwebbz28

iTrader: (31)

Good cap? Antifreeze good?

LS6427

iTrader: (2)

Answer these?

When it does overheat, does the coolant boil over/out? Or does it just get hot and NOT loose coolant and not bubble and make noise in the radiator?

When you take the cap off (cold engine) and start it up and wait for the engine to reach operating temp....do you see the coolant flow i nthe radiator? AND....does the coolant level stay topped off or does it drop down?

edit......anything, like a bag or newspaper, jammed up in front of your condensor.

AES Racing

iTrader: (6)

why isn't the fan turned on at a lower temp? I think 179º is the lowest they can turn on at with E38 PCM, it should be adjusted to that temp.

iMpoSStoR

When we replaced the head gaskets we had the heads milled .005" just to make sure there wasnt anything wrong with the heads. The car still runs good and all but heats up.

Cap and antifreeze with water wetter are all new. Actually it is the second new cap.

1. it doesnt loose coolant and havent noticed any boiling or radiator noise.

2. yes the coolant flows and stays topped off.

3. nope.. nothing infront of radiator.

doesnt make a difference.. i tried turning them on with the scanner at 130 and temp still goes up... takes a lil longer but same result.


Today im gonna try just changing the temp sensor and if that doesnt work some different heads.. thank you for ya'lls input.. i really appreciate it.

1904gto

iTrader: (4)

wat if the sensor is bad on the head? could that be the case? because your not losing water or coolant not bubbling over you say new radiator
have you pressure checked it?

Glenn B

iTrader: (5)

I was going to recommend this too.
If nothing else it seems like you have replaced most other parts with new.
Hope this helps.
--Glenn

LS6427

iTrader: (2)

Probably a bad (new) t-stat.

Next time it gets hot, like up above 220*, pull over, pop the hood and put your hand on the intake. If you can leave your hand on the intake for more than 10 full seconds....you're not getting hot. Go get a new temp sensor. If you can't keep your hand on there for more than a few full seconds......get a new t-stat.

You can also take the t-stat out, hook the housing and hose back up. Go for a drive on the highway at steady cruise speed for 15 minutes. If temps stay normal, get a new t-stat. (in the city, stop and go, without the t-stat, you'll get hot, so don't do that too long).

.

lt1pwr1

iTrader: (1)

This may sound dumb but did you change the thermostat, radiator, water pump, head gaskets, and added a fan(pusher) infront of radiator after it started to overheat or was that done when you put the 408 in? And were these aftermarket parts?

I ask because I chased my tail on our truck FOREVER because the water pump was leaking so I went to autozone and got a new one along with a t-stat. Put it in and the truck kept overheating. I wasn't losing coolant at all though this time. Confused the heck out of me until I finally pulled the water pump back off and the impeller part was loose from the pulley part if that makes sense? So in other words, I could turn the pulley part and it wasn't moving the impeller... Now I always check to make sure they are moving together haha. Anyways, the chances of that happening twice are pretty rare I'm sure but it might be a thought if it gets down to it I guess.

SOMbitch

iTrader: (8)

Shoot the head temps with an infared heat gun and the should be within 5* of coolant temp to verify CTS accuracy.. I shot the CTS on mine and it was dead on with my temp guage....

iMpoSStoR

already changed the ECT sensor.. pressure checked it as well and everything is fine... i think.. it held pressure so i'm assuming its good.

i thought it was a bad new thermostat.. its the second new stat in there but no luck..

everything was done when it started overheating... after the 408 was already installed.

we've tried 2 different ect sensors, aside from the one that was originally on the car and all 3 have read the same.. with the same results dont think its going to be the problem..

However i was reading in another forum that the fans procharger supplies tend to go out at time.. no completely die but not flow the cfm they are supposed to.. going to give spal a call tomorrow and see what they tell me.. i'll keep ya'll informed.. thanks for the suggestions though.

jayeandre

I'm having the same problem. I took off the cap and when it reached op temp the fluid did drop. What does that mean?

Rick Williams

My stock '06 loses coolant when it overheats. It seems to be leaking from the reservoir, but I pulled it and no problem there. It does boil over. I changed the water pump, and T-stat, and can't see any other ares that are leaking. No water in the oil either.

time3777

Are you sure you installed the correct head gaskets?