2015 1500 Denali 6.2L P0308 & P050D with CEL and coolant lost

zolt101 · June 13, 2017

The truck has 29,400 miles on it. I first noticed 3/4" of engine coolant below the FULL COLD line so I followed the manual and refilled it with a mixture of 50/50 DEX COOL then I let it sit over night. Next day proceeded to turn the engine on and got a steady CEL. Also noticed the coolant level was lower than what I filled it up to by 1/4". Started the truck again, this time I got a blinking CEL. Took it down to the dealer ship, they scanned it and got the P0308 & P050D. Next day I called them to get an update, the guy told me there is an internal coolant leak and they'll have to replace the #8 cylinder head and that GM sent out TSB#PIP5498 regarding the issue. The day after that he emailed me back and said that they ran the coolant leak tests and found no leak, it's just a bad fuel injector on the #8 cylinder and my truck will be ready for pickup tomorrow... Makes me wonder if they're just doing this to avoid replacing the engine per the TSB... I'm just looking for other opinions on this.

http://www.corvetteactioncenter.com/tech/knowledgebase/print-1364.html

2strokesmoke · June 13, 2017

The truck has 29,400 miles on it. I first noticed 3/4" of engine coolant below the FULL COLD line so I followed the manual and refilled it with a mixture of 50/50 DEX COOL then I let it sit over night. Next day proceeded to turn the engine on and got a steady CEL. Also noticed the coolant level was lower than what I filled it up to by 1/4". Started the truck again, this time I got a blinking CEL. Took it down to the dealer ship, they scanned it and got the P0308 & P050D. Next day I called them to get an update, the guy told me there is an internal coolant leak and they'll have to replace the #8 cylinder head and that GM sent out TSB#PIP5498 regarding the issue. The day after that he emailed me back and said that they ran the coolant leak tests and found no leak, it's just a bad fuel injector on the #8 cylinder and my truck will be ready for pickup tomorrow... Makes me wonder if they're just doing this to avoid replacing the engine per the TSB... I'm just looking for other opinions on this.

http://www.corvetteactioncenter.com/tech/knowledgebase/print-1364.html

In that TSB it also says the piston would be steamed cleaned from the coolant mix.

I would start with a borescope camera inspecting the cylinders piston crown through the spark plug holes for cleanest. One or 2 of the pistons will show very clean compared to the other 6 if you have an internal block, or head leak.

Good luck