I have a 04 that has 153k on it. 4" cat back exhaust with no cat. SCT tuner running a custom street tune. New FMIC with the extra tune on it.

Head gaskets where done at 90k along with ARP studs. EGR cooler, The oil cooler was cleaned, New coolant tank. 1-new head and The cooling system was flushed at 90K. All done by the dealer along with some other items. Installed a bypass coolant filter at least 60k miles ago.

I have been having a no heat issue sometimes at idle this past winter and a mystery loss of coolant. I replaced the cap with a OEM one.
I did a vacuum test on the coolant it held at 25 inches for well over a 1/2 hour. Pulled the egr valve it looked somewhat like tar inside not 100% dry. At startup it sometimes blows some white smoke and other times it's black smoke.
I've had the scan guage on for the last week to check my deltas.
Running 65mph the deltas stayed around 10 degrees diff.
Running 70mph the deltas stayed around 14-16 degrees diff.
Yesterday just running around rural roads 55mph and under the deltas stayed around 10 degrees diff.
I have not found a lower pressure gauge to do a coolant pressure test.
It does look as though it has burped the cap. Because of the deltas I'm thinking a plugged oil cooler my be the problem.
Any ideas?

 

Your deltas are within specification. Your intake manifold will never look dry unless you've diverted the PCV system to atmosphere. White smoke indicates unburned diesel and that will happen on some cold starts.

 

Well you're in line with the temp splits (at 65). Did you have head studs put in when the hg was done? You quite possibly could have a bad egr cooler. When mine was bad I had the heat go out once or twice and had frequent puking. It's pretty much one of two things-hg failure or egr cooler failure. I was lucky and was egr cooler. Did the Ipr egr cooler delete and no problems since. Also it's time for you do do a coolant flush (due to miles-if you don't have elc in it)

 

No heat could be a blend door issue.

 

Yes I had ARP studs installed when they did the HGs. I hope it's not HGs again.
I do get heat at times right from the get go but other times I do not. Normally when I don't have heat I would relieve the pressure on the cap and that seemed to work.
I plan on hooking up a gauge to the coolant system to check pressures.

If the vacuum test for the EGR passed could it still be the EGR leaking only when it's hot? My coolant system does hold pressure overnight.

 

Still trying to diagnose what's going on with my truck. I did talk with a good diesel shop in my area about doing head gaskets to get some figures. Well not sure if I want to dump that kind of money in a truck that's 11 years old with 160k on the spedo. If it's just head gaskets could be around $4500 if the heads are cracked could be up to $8000. So I decided to do a couple more tests.

Did a combustion gas check in the coolant and it failed. Turned from blue to a greenish color.

Installed a pressure gauge on the coolant line. Truck was pretty warm about 165 when I started it. Drove a short bit till I got to a faster road. The pressure was at about 4psi Got on the faster road I jumped on it some but no way close to WOT. The pressure built pretty quick to 14psi then held. But I let off the gas and it quickly jumped to over 16psi. I was not able to do any WOT romps since it was rainy and lot's of traffic. If I pushed it a little it would get over 18psi then drop back and hold at 16psi On youtube Diesel Tech Ron mention that if the pressure jumps quickly it's normally a EGR cooler and if it's a HG it builds pressure slower. Other people all say if it build fast it's a HG. So which on is it?

I keep watching my deltas. It's been cooler so my truck coolant temp never goes over 185. Normally around 179 my oil temps are between 185 and 194. The coolant temp swings back and forth about 5 degrees.

I think I'll pull the EGR valve again.

The truck had HGs done by the dealer at 90k and ARP studs

Any suggestions ?

 

This one is kinda tough. Sorta bad here and not exactly right there and on the web on top of that. With that disclaimer, I'll share my thoughts .

First, the truck isn't getting up to proper operating temp, I'd put a new thermostat in it. 15° does make a difference (170° to 195) in fuel trims and fuel timing. Getting up to full temp may make a difference in the oil/coolant temp split also but given the temps you posted it is getting close enough that if you tear into it, I'd replace the oil cooler. I wouldn't go into it for just that yet though.
While changing the stat, I'd flush the cooling system including the heater core, catch the drain and inspect for trash. I'd also pull the EGR valve and clean up in there as good as possible and try to at least get the goo out of the very front- bottom area. After servicing the cooling system I'd burp it one time, service it up to exactly the low level on the degass bottle (or make a mark on the bottle with a sharpie if you miss it) After driving a day or two, I'd drive it kinda hard at full temp then park it with the tail end pretty high up on a curb, ramps, stands or whatever, leave it set a few hours or overnight then pull the EGR and check for wetness. If it lost coolant and the EGR is wet the cooler has failed, level drop and dry-head gaskets are suspect. No drop, problem with heater core blockage or blend door/vacume issue.

Testing for exhaust gasses in the coolant doesn't help determine where it's coming from(headgaskets or EGR cooler) That test will be a fail no matter where the leak is. I hope I don't offend anyone, but I don't believe you can tell for-shure where the leak is with a gauge either. Some very knowledgable posters here say they can but one of our Tech's posted a video a couple years ago showing a pressure gauge on the degass bottle that would move almost like a tachometer when the engine was revved. That one was a EGR cooler.

 

Rusty
I have a new stat sitting on the bench just have not installed it yet. So your saying that if it is still puking after all that than it's head gaskets?

 

That's my thinking. Coolant loss and high coolant pressure with dry EGR and intake is headgaskets.

 

Just a little update
Took the truck to a local diesel shop that does quite a few 6.0l builds.

The head gaskets where bad found a leak on the rear of the passenger side head. Both heads where cracked. The tech called me and wanted to know who did the previous head gasket install. Which was a dealer. I HAD them put ARP studs in at that time. He said he doesn't think they torqued them correctly since he was able to loosen them up 1-handed. He said normally with studs they can be a problem to loosen. He thinks that may have contributed to this failure.

Going to do a EGR delete, new oil cooler, 2 heads with fire rings, new OEM gaskets, blue spring, coolant flush and use CAT coolant, new pass side exhaust manifold since it was a little too rusty, reuse the ARP studs plus I'm sure a few other things.

He did say the cylinder bores looked great he could still see the original hatch marks on the walls from the honing.