High EGT, No Boost and a major boost leak!! PLEASE HELP.

[VNL670]

(10-08-2016 )Hammerhead Wrote:  

(10-08-2016 )gearhead Wrote:  I would unplug egr valve or block the intake would be a better way. I think that the egr is blowing open or something. This would be my first check for this problem for sure. Not leave it this way but for test purpose. The delta p could be reading wrong and causing the egr to do the wrong thing.

I agree with gearhead completely.
Logical testing order;
1 CAC
2 EGR circuit
3 air compressor
These are the most likely and easiest to test without the aforementioned plugs...
You seem to have eliminated #3. I say "seam to" because it wasn't tested "in situ", so you have eliminated the plumbing but not the compressor itself.
You're convinced it's not #1, but test it anyway.

You are correct on the air compressor part. We are going to retest all 3 once we get the proper tools to pressurize the whole engine as Rawze and the other members mentioned. We'll keep you guys updated.

[VNL670]

(10-08-2016 )Nilao Wrote:  

(10-08-2016 )VNL670 Wrote:  Here is the update on the fan problem. We applied direct pressure (110 psi) to the fan directly, using a regular tire air valve with a hose clamp over the line going to the fan, but unfortunately it did not disengage. So we concluded that the fan clutch is shot!

My fan clutch will stick if it sits for several days after a rain. You could apply air and smackmit with a hammer. Works on mine every time.

Will give it a try Sunday morning. Thanks for the tip.

[gatow900]

(10-07-2016 )Hammerhead Wrote:  I have seen something similar to this about 10-12 years ago...
It was also one of those unbelievably wonderful DuraLite ... ahem "Best on the Market" CAC's.
DuraLite doesn't, or at least didn't used to, weld in the cooling tubes. They use a rubber grommet to seal the cooling tubes into the header manifolds. What occasionally can happen is that the grommet gets nicked, the manifold doesn't get cut right, or after time gets weak, and then holds seal until pressure forces it out of place breaking the seal. Breaking the seal takes more pressure than holding it open, which makes it difficult to find without pressure testing the CAC.
DuraLite's used to be made in Calgary, AB and I've been to that facially before they moved the manufacturing to Mexico. The idea of using a grommet is good as it allows the tubes to flex in the manifold without cracking like OEM welded, but the problem is in order to have enough grommet material to hold seal under pressure they have to space the cooling tubes further apart. This means less tubes, which equates to less flow capabilities. Trucks with large CAC's don't show the effects as much trucks with smaller ones. The smaller the CAC, the larger the percentage of drop by the reduced amount of tubes.
We've asked DuraLite to make one for the T800/C500 wide hood. These trucks have massive CAC's. They are designed for heavy loads at slow speed so the CAC in them is probably the same size or bigger than the rad in a VNL, and because our sister company uses the C500 as Prime Movers they flex the crap out of them so they wanted to give this option a try. They won't make it because it can't meet the air volume low speed heat exchange demands required. What does that tell you?

Hey hammerhead my w900 short hood has a stock CAC that looks like dura lite but stock check it out vin#248888 it might be what ur looking for

[Hammerhead]

(10-09-2016 )gatow900 Wrote:  Hey hammerhead my w900 short hood has a stock CAC that looks like dura lite but stock check it out vin#248888 it might be what ur looking for

I know a few guys with W909B's and yes they are bigger than a 900L, but the 800/500WH is still about 6-8" wider than the B.
They're about 1800sq/in. They hold 20gallons of coolant compared to 17 in the 900. The C500 custom cores our sister company uses holds 24 gallons.

[VNL670]

Here is the latest update.
-Nilao thank you for the tip on the fan!! It actually worked! Applied air pressure and smacked it gently and wala! working the way it is supposed to.
-A/C is working with no leaks.
-Tackling the EGR tomorrow morning.

[Nilao]

That's what we're here for. Sharing knowledge and tips.

[VNL670]

Hi guys and sorry for the long delay. It turns out that the little 4 inch hose on the back of the engine, (It connects the back of the EGR cooler to the metal pipe going to the intake) was in very bad shape (check out the pictures). It looked like it rubbed through or melted through. Either way, I have ordered the hose and will install it tomorrow and recheck for any leaks. Will keep you guys posted.

[Rawze]

Make sure that thing does not have some kind of cheap after-market EGR cooler on it,.. It will cause those kinds of problems and eventually serious engine problems too.