I think I have a pinhole head gasket leak on my 6.0. Thoughts?
I bought a 6.0 around this time last year. I got a smoking hot deal on it, mainly because it needed work, like injectors and suspension work. Came studded with ARP 2000 head studs, but no receipt on the work. Can clearly see it’s been studded, engine was removed because of marks on bolts and how little oil it has on the block for 200k miles. It was barely running when I bought it and wouldn’t move under its own power.
Bought it, fixed it, and drove it. I’ve driven it every day for the last year, and after fixing numerous coolant flow issues, bad parts, shitty work, and everything in between, I’ve noticed it starts venting out of the cap after long drives. I’ve replaced the cap 3 times hoping that I had some bad caps. Recently, I drove it down to the beach (about 3 hours one way), and noticed the longer I drove, the colder my coolant temps got. I thought my thermostat was stuck open, but I just discovered that my thermostat hangs open when it starts to vent coolant out of the degas bottle. I believe that the pinhole leak develops under moderate boost when the engine has been heat soaked for 45+ minutes, and it’s adding pressure that has to be vented and the thermostat spring is weak enough to be overcome by excess pressure. I have no idea if the heads were o-ringed, if the heads were decked properly, if the head bolts were torqued properly, but it looks like I’ll need to pull the heads soon and re-seal them.
Thoughts?