Overheating towing with Denali 6.2L - Losing my F'n mind!!

[EfrainlCazares]

I have an '09 Denali with the 6.2 and interested to hear what the issue is/was.

Check oil pressure at idle hot. If below 20 it will go into limp mode, if below 17, it will shut down. May look like an overheat problem but really a low oil pressure problem. 6.2 motors had problems with cam bearing wear causing low OP. I had this problem with my 08 6.2. Had to replace engine do to GM screw up with cam bearings.

Guess what??!! Getting my engine replaced....... While driving back from Seguin to Killeen, TX about 10min for house started hearing a tapping sound. Towed it in to dealer today and they call me that engine needs to be replaced. I had taken a video and showed them, before they took it in. Luckily, I bought an extended warranty on it!!!!

 

[puckhead]

I have seen failed head gaskets cause near zero coolant loss, yet cylinder pressure will over come the coolant system thus causing an air pocket that the water pump is incapable of pumping. Cranking the engine without the drive belt installed will quickly reveal a failed gasket or cylinder head. Blocks failing is truly an anomaly I have not seen on these motors, yet failed heads and gaskets are somewhat frequent.
In general white smoke exiting the exhaust is highly uncommon these and would require a major coolant leak to produce this type of result. Oil in the coolant would not likely cause an overheating condition because of the area the coolant is leaking into, this is also a fairly uncommon failure in my opinion.

So I'm looking for bubble in the overflow tank for one.

Then I can also take the belt off and try to turn the motor over? What would I be looking for in this circumstance?

 

[Ming15237]

So I'm looking for bubble in the overflow tank for one.

Then I can also take the belt off and try to turn the motor over? What would I be looking for in this circumstance?

Remove radiator cap have engine drive belt off, coolant level in the radiator full. Have someone crank the engine, if you see any bubbles you have an internal leak. Repeat with a warm engine if no bubbles.

 

[ncampion]

Guess what??!! Getting my engine replaced....... While driving back from Seguin to Killeen, TX about 10min for house started hearing a tapping sound. Towed it in to dealer today and they call me that engine needs to be replaced. I had taken a video and showed them, before they took it in. Luckily, I bought an extended warranty on it!!!!

You're lucky, cost me ten grand.

 

[JEFFC]

OP: Any word?

I am in the process of wrapping my fuel lines right now. I attached a picture of the fuel line, just want to make sure I'm doing the right one. It also looks like there is a metal crossover to the other side of the motor. Is this correct?

Also noticed that some wire loom in the area behind the alternator was brittle and crumbled when I touched it is one that looks a bit melted. I recently replaced the alternator but could it overheat to the point of vapor lock? View attachment 201776 View attachment 201777 View attachment 201778 View attachment 201779

The bottom photo is the fuel injection fuel rail which does need to be wrapped. The fuel line runs from the fuel rail down the backside of the engine and over the transmission and also needs to be wrapped.

 

[gpracer1]

Where do you guys live that are wrapping your fuel lines?
Just curious as I live in Phoenix and it was 111 the other day in rush hour for my 30 mile drive with the AC on high and I don’t have any fuel lines wrapped or vapor lock.

There must be something else going on.

 

[intheburbs]

Where do you guys live that are wrapping your fuel lines?
Just curious as I live in Phoenix and it was 111 the other day in rush hour for my 30 mile drive with the AC on high and I don’t have any fuel lines wrapped or vapor lock.

There must be something else going on.

Temperature is not the only driver of vapor lock. Higher altitudes reduce the boiling point of liquids, and this can also increase the possibility of vapor lock. Phoenix is only about 1,000 feet above sea level. Divide, CO is 9,000 feet above sea level. Big difference. Water boils at 210°F in Phoenix, but it boils at only 195°F in Divide. Fuel behaves the same way.

 

[mattt]

Remove radiator cap have engine drive belt off, coolant level in the radiator full. Have someone crank the engine, if you see any bubbles you have an internal leak. Repeat with a warm engine if no bubbles.

There is no radiator cap on NBS trucks, that is why he asked what he did.

 

[gpracer1]

Temperature is not the only driver of vapor lock. Higher altitudes reduce the boiling point of liquids, and this can also increase the possibility of vapor lock. Phoenix is only about 1,000 feet above sea level. Divide, CO is 9,000 feet above sea level. Big difference. Water boils at 210°F in Phoenix, but it boils at only 195°F in Divide. Fuel behaves the same way.

Yes I completely understand this. Phoenix is only 1400 ft but at 60 psi the fuel should not be an issue since 60 psi is 60 psi. Boiling water is at atmospheric pressure which varies with altitude unless you have a pressure cooker.

 

[JEFFC]

Yes I completely understand this. Phoenix is only 1400 ft but at 60 psi the fuel should not be an issue since 60 psi is 60 psi. Boiling water is at atmospheric pressure which varies with altitude unless you have a pressure cooker.

Agreed, altitude does not contribute to vapor lock on fuel injected systems with the pump in the tank. It could contribute to vapor lock on older fuel systems with the pump at the engine causing vapor lock between the pump and tank.