Opinions......watch to the end

 

What was the temp at when testing and do you still have the EGR system intact?

 

No egr. Do you mean outside temp or coolant temp? Coolant temp was at operating temp (190ish). Ambient was about 65. Fluid changed color slightly.

 

I was talking coolant temp. Is the EGR gone or just welded close?
If welded what was used to make the plugs?

 

Welded closed and bypassed by a straight up pipe.

 

Hmm, Sort of kills that idea.

 

So is the amount of bubbles normal or related to issues? Why do the bubbles stop when we first put a load on and then come back? I know what the color change most likely means 😰

 

You should not be seeing any bubbles. After all it is a closed system.

I had hope that your EGR was still intact. If that was the case once your past 150ºf
the EGR starts to function. That is why the temp question. With it at normal operating
temps and the load and higher RPMs then you could see a leaking EGR cooler.

But because you no longer have a functional EGR system that Idea is a bust.

Unless and I am thinking as I go on this one. There is a way that you could still
get bubbles into the system from a bad EGR cooler. The bubbles would be coming
from the pressure in the intake blowing into the EGR cooler from the intake side.
But that still does not cover the color change that was showing. No mater what you
do I would do a pressure test of the cooler before going too far into pulling the heads
for a gasket replacement.

You will need a tank of water to submerge the cooler in and use some rubber plugs for
the openings with one having a air fitting on it so you can pressurize the cooler.
Here is the TSB that covers the testing. Your going to have to make a few changes
with the test because of the welded up cooler.
Looks like your going to need 30PSI air pressure to test the cooler while it's under
water. If you see bubbles it bad.

 

Any other thoughts on this? I'm tempted to tear it down to fix the leaking bed plate and do cam and lifters, and obviously replace the headgasket while I'm at it. Headgaskets are under warranty but the guy that did them has had the truck twice now to figure out the issue and says it's not headgaskets. He supposedly spent a whole day tearing it down to check out the egr cooler (don't know if he pressure tested it), injector cups, and head stud torque. Said he did a block test and it was negative but I wonder if he put a load on it all all. His reasoning for the degas pressure was coolant deadheading at the back of the cylinders but I haven't been able to find anybody who has seen that happen.

 

I hate to say that I am thinking head gaskets too.
You could try and pull a vacuum on the cooling system.
Once all the hoses have collapsed and any air pockets
have cleared you should not have any more air coming
into the system.

This is starting on page 2 of the PDF I posted above.

3. EGR Cooler Leak Test On Vehicle:
NOTE
NOTE: A LEAKING EGR COOLER CAN CAUSE EXCESSIVE WHITE SMOKE, INTERNAL COOLANT LOSS
(WHICH MAY RESULT IN A HYDRO-LOCKED ENGINE), AND/OR PRESSURIZED EXHAUST GASES ENTERING
THE COOLING SYSTEM. THIS MAY RESULT IN VENTING FROM THE DEGAS BOTTLE CAP, AND APPEAR
SIMILAR TO A LEAKING HEAD GASKET.
a. Install RADKITPLUSA 078-00592 on the degas tank.
b. Regulate shop air to 100 psi (690 kPa) and apply vacuum to cooling system until gauge stops
decreasing or 20 inches of vacuum is reached. Degas bottle coolant level must be set to MIN line
with a cold engine to allow sufficient space for vacuum.
c. Hold vacuum and allow vacuum to stabilize (allow 60 seconds for vacuum to stabilize).
(1) If vacuum holds steady over 15 minutes go to Step 5.
(2) If vacuum does not hold steady over 15 minutes go to Step 4.


RADKITPLUSA 078-00592 is just like the Radvac system and works the same way.
A venturi is used to create a vacuum to pull all the air out of the system.

I would give these steps a try first. Also did you "T" a
pressure gauge into the coolant system and check the pressures?

 

These might help:

 

Yes I'm monitoring coolant pressure and when I run it hard it gets up to 16psi. It seems to get there easier than it did a few weeks ago. I can't get coolant to puke however, even though I see it top at 16psi and start venting off. It did puke earlier this spring though and that's what made me start questioning what was happening. I still don't understand how anything egr related could be the issue since it is welded and straight up piped.

 

An intake side failure of a weld would allow pressurized air to enter the
cooler and it there is a leak you can guess where it would go. That is
why I think you still need to test that cooler to be sure that it's not
leaking. You can do the park nose down over night and see if you have
any coolant int the intake under the EGR valve.

 

I noticed when you dropped the rpm, the turbo farted a little at the end .

 

Just a thought but maybe the water pump pulling air in at the shaft? No impossible and another theory before headgaskets.