Recently bought the truck. 2003 f350 6.0 srw
Brought it in mechanic said it has combustion gas in the reservoir. It didn't seem bad barely turned dark green from the blue.
So I did the T off the coolant reservoir test. Here's what I saw/got, with as much detail as I can without a video.
I'm in MN, temp during this test was 12°F outside
I'm using a 0-15 psi gauge
Truck was off for 3hrs
I ran it for a minute or two before taking off, babying it till I got to my location (freeway with a decent up slope) this was 4 miles to location basically flat little rollers.
Pressure got to 14.5psi by the time I even got to the light to get on the freeway engine was just a notch under normal/halfway on the gauge cluster got onto freeway and slowed to 50 and floored it to 80, it went past the 15psi after I let off and then released out the cap as designed. It makes the jump in pressure when i let off, if that matters?
I turned around and babied it back for another pull it dropped to 11.5-12 just before i got back on the freeway again slowed to 50 floored to 80 this time only went to 13psi again it makes this jump to 13psi right as I let off.
Turned around again babied it back and it dropped to 10 I pulled into a parking lot close by and it dropped to 9 by this point. I shut down and released the pressure in the tank, also looked inside and noticed bubbles/sort of foaming look fired back up and got back on the freeway again for another pull pressure got to like 3 or so just getting back to the on-ramp went from 50-80 floored braked to 60 went to 80 again and it went to 8psi, flooring it twice since it seems to jump when i let off after being on it.
Did the above again exactly the same and got to 10psi.
Cruised to a gas station 3 miles away after and it settled while driving at 8psi parked it left it running ran in for about 4 minutes came back and it was at 5psi not a lot of heat blowing out at idle like this fan was at the 3rd dot. Drove it a mile home and it went to 8psi.
Wow that's long, sorry but I'm new to diesels and figured the more descriptive the better. Coolant looks fine as far as no oil look in it. I don't believe I'm loosing coolant besides what I blew out. this morning I topped it off cold to the level of the sticker that the dealer put on just a notch above the stickers min line.
Truck is stock besides 4" straight back off stock down pipe.
What do I do next?
If its just a egr delete and oil pump i can do it here/afford to do it here. If its the head gasket i cant afford it without driving this thing to California where the old man is a diesel mechanic and said we can pull the cab off and get at it.
Opinions other test to do?
I don't see white smoke coming out but then again I'm in MN and its hard to tell whether its white smoke or just it being cold outside!?
My first diesel