Help: 2008 6.0L Vortec Max Problem

[coldLBZ]

My Dad is having issues with his truck. It's a 2008 GMC with the 6L Vortec Max. The DIC is saying "Engine Hot/AC Off", it is currently -20C and the truck was plugged in overnight. The electric fans stay running full blast anytime the truck is on. The engine temp on the gauge won't come up, the heater is blowing luke warm air at best, and the truck has lost some coolant, none has hit the ground though. There is also no CEL on. Anybody have any ideas, thanks.

 

[Turbo Buick 6]

My Dad is having issues with his truck. It's a 2008 GMC with the 6L Vortec Max. The DIC is saying "Engine Hot/AC Off", it is currently -20C and the truck was plugged in overnight. The electric fans stay running full blast anytime the truck is on. The engine temp on the gauge won't come up, the heater is blowing luke warm air at best, and the truck has lost some coolant, none has hit the ground though. There is also no CEL on. Anybody have any ideas, thanks.

Has anything been done to the truck recently that could cause air to get into the system?

 

[coldLBZ]

The truck was bought used with about 8000 miles on it. We haven't touched it though.

 

[Turbo Buick 6]

Is the coolant hot? If it is and the heat isn't working well that is usually caused by air. Unless is has a heater valve....not sure if GM trucks do

If it is overheating that can cause steam to form in the heads and if the steam gets into the heater core that can cause some funky problems with heat. It cause also cause the coolant to be low. Top the coolant off and see if you still have the problem. If you do then check to see if it is actually overheating.

Again I'm not sure on these trucks but many cars have a different temp sensor for the fans. I know my Buick had 3 from the factory. ECM, Fans, and one for the idiot light

 

[coldLBZ]

With the truck just being driven you can put your hand on the upper rad hose comfortably, it's maybe almost too cool.

 

[Turbo Buick 6]

With the truck just being driven you can put your hand on the upper rad hose comfortably, it's maybe almost too cool.

Just a guess, but maybe the sensor for the ECM, which I belive controles the fan is broken and maxed out. And the low coolant was just a coincedence sp. And it won't get hot because its soo cold and the fans are running

How low was the coolant?

 

[coldLBZ]

Coolant looks to be about 1qt low. It could be a sensor issue, with the fans running full bore at this temp it probably would have trouble making heat.

 

[Turbo Buick 6]

I'de top it off and get a new sensor. Who knows, maybe the sensor is leaking. I have seen them leak out where the wires come out of them

 

[coldLBZ]

Cool, thanks for the help. :hug:

 

[Turbo Buick 6]

Cool, thanks for the help. :hug:

No problem. I would check to make sure it is a seperate sensor for the ECM and fan than it is for the guage. I'm just going off of general car knowledge and if they aren't different sensors my whole theory is shot

 

[coldLBZ]

My Dad was checking more things, and he figures it's a headgasket. The oil was about 1 qt too full. Pretty much the same amount of coolant it lost.

 

[Turbo Buick 6]

My Dad was checking more things, and he figures it's a headgasket. The oil was about 1 qt too full. Pretty much the same amount of coolant it lost.

if you let it sit and pull the drain plug for the oil you should get all the coolant first...if there is any in there

 

[coldLBZ]

We'll give that a shot on saturday, it's supposed to be warm out. Thanks again for all of the advice.

 

[coldLBZ]

Just a quick update. There was coolant in the oil, and the truck was very hard starting. It left on a roll back yesterday morning. Probably won't know what happened for a while though.

 

[jraymer]

Its an 08 so I would just take it to the dealer for warranty work.

 

[coldLBZ]

It's sitting at the dealer right now. So only time will tell.

 

[LBZ]

Damn, even the gasser's have head gasket issues-what gives??

 

[coldLBZ]

Well Dale, it is a 6.0L:rofl:. We go pick up the truck tonight. They couldn't replicate the problem, they say the truck is fine. They did nothing on it. Come on, WTF. We'll see how long this lasts now. That's why my truck will never go back there for anything.

 

[coldLBZ]

Got the truck back now. Everything seems ok. Normal temp, oil pressure, starts fine. I dunno. They did change the oil though which costed my Dad $60.00.