Conflicting info on coolant pressures
Howdy, 1st post. Love this site.
So I just picked up the 06 in my sig.
Here is whats up: I have found info saying 3-4psi is normal and 16psi or higher is a head gaskest more so then not. Others are saying it is the rate of increase, cause one might have a bad oil cooler starving the egr and boiling some coolant causing slow pressure increases. As compared to a quick increase with a bad head gasket.
I teed my coolant pressure gauge into degas line.
From cold the pressure does not even start to climb until operating temp is reached and then driving HARD 55-75mph I can GRADUALLY reach 16psi and it can settle to 14psi cruising or slowing around. I also can get it up to almost 20psi flooring it from 0-75mph from 16psi. Leak down after shut down is about .5psi/min. Put a new 16psi degas cap as soon as I picked it up.
Once warmed up and the PRESSURE is RELEASED to 0psi, I can floor it 0-75mph and get it barely to 4psi. Of course if I continue to drive it hard it will eventually reach 14-16psi. NOW I can drive very conservatively under 55 and not see 14-15psi for a while.
Background: I bought this truck on an auction $13k supposedly worth $16k+. Drove it home 300 miles. No smoke, ran awesome averaged over 18mpg. The dealer/person I bought it from said they just replaced the egr CAUSE IT WAS LEAKING. He was not sure if they replaced the oil cooler...I do not think so.
When I got it home and inspected more closely, It clearly looks like they did the egr and not the oil cooler, based on the respective bolts and parts cleanliness on the engine. I called the dealer right after picking it up after finding OIL IN THE COOLANT, he said that was normal and they DID NOT FLUSH THE COOLANT. I started to get confused cause I thought the egr was only exhaust and coolant. Hmmm he said maybe they did the oil cooler, not sure. He just know they DID NOT FLUSH THE COOLANT. I have removed most of the oil in the degas bottle to only see more slowly make it into the degas. The coolant level seems to be steady.
Me thinks the oil cooler is bad, but wait. I performed the combustion gas detector tester for the degas bottle. The test showed positive for combustion gas. Oh no hg?!? Wait they had a failed egr cooler and did not flush after the job. HERE IS THE QUESTION: can combustion gases under pressure dissolve into the liquid (like soda) during a egr failure and stay there for a while. They said they hardly drove it after the job. I buy that story cause an inter cooler boot blew 1st big hill on the freeway.
I'm being nice to the dealer guy right now cause I want some info, I have not found out yet if they "think" they "really" did the oil cooler. I spoke w/him today I'm afraid he is not going to call me back after speaking to his "diesel technician"
Side note: Local craigslist i picked up $2100 worth of new parts for $700. Including arp studs, stock gaskets, oil cooler &kit, NUC bypass oil filter kit, sinister coolant filter kit, icp sensor, various gaskets and update/rebuild kits. Guy just bought a blackwater w/studs after seeing the engine tore down.