High pressure in cooling system

[DZL JIM]

Anyone experience high pressure in the cooling system?
We got a truck came in here with low coolant and lots of white smoke, it's running about 20 psi in the cooling system and has now blown the radiator and is leaking there.
The EGR has been ******d, and we are not sure if a turbo failure can cause pressure in the system with these, a blown head gasket is more common, or something else?
Any tips on what to look for is much appreciated.

 

[jvgviper1]

Some have had problems with the radiator caps not holding proper pressure resulting in numerous problems.

 

[jvgviper1]

Expansion tank resouvior cap

 

[DZL JIM]

It's not coming out the cap or res/tank, it's coming out the exhaust.

 

[redneck1]

Trying to figure out what you mean. The factory cap on my 16 is 20, so the pressure isn't too big a deal. Don't see how a blown turbo could pressurize the coolant, even if it was cracked out the exhaust housing, you only get maybe a couple psi back pressure at idle. Unless your getting oil pressure in your coolant, then you would have the pressure, but you'll also would have oil in your coolant then.

Personally, I'd pull the turbo and try to figure out if the coolant entering through the turbo or further up stream, like a blown head gasket. You never know what you'll find until you tear into it. Seems like a cylinder contribution test or compression test should tell a little on your head gasket. Good luck.


Beyond the edge of reason

 

[DZL JIM]

Thanks for the info.

 

[CATDiezel]

One of 2 things can be tried for a quick check.

1st. Block to coolant supply and return to the turbo for testing purposes. It won't hurt the turbo at all....

2nd. After a hot shutdown let the engine cool and pull the glow plugs... remove the hpfp harness so the engine will not start and crank the engine to see if one or more cylinders puke coolant through the GP's.

The hot shutdown is rather crutial or you will be chasing your tail.

 

[jvgviper1]

Some have had cooling system problems due to boiling because of the pressure cap not holding at design limit, causing radiator to blow out leaks and other issues. This was written about on another forum.

 

[sootie]

cracked head possibly?

 

[DZL JIM]

We just got the job done, pulled the heads and had them pressure tested and machined flat. They Tested fine and only needed .003" to flatten. Truck fired up when we were all done, and ran great for us. Customer calls shortly after picking up the truck and says it's doing same thing, lots of smoke and drinking coolant. We are pretty lost at this point. Everything checks out, it just doesn't make sense.
Cracked block?
Cylinder cavitation?
Any thoughts on what to look at next?

 

[sootie]

what does the oil look like? does it look sludgy or boogery?

is the downpipe wet? turbo shaft play?

 

[DZL JIM]

Before we started Oil was fine, down pipe was wet (as expected), no shaft play in turbo.
Waiting to get truck back to go over again.

 

[CATDiezel]

Cracked water to air aftercooler.

I chased a similar problem on a 700hp cat engine about 8 years ago. Could not find it unless it was hot. Took the water/air cooler put and tested it and it was fine. Until I tested it in a hot vat tank. Then the problem arose!!

 

[DZL JIM]

Cracked water to air aftercooler.

I chased a similar problem on a 700hp cat engine about 8 years ago. Could not find it unless it was hot. Took the water/air cooler put and tested it and it was fine. Until I tested it in a hot vat tank. Then the problem arose!!

We thought of that but that system was fine, coolant was low on the primary/engine cooling system.

 

[CATDiezel]

You've got your troubleshooting work cut out for you then!

I suppose it very well could be the turbo. We pulled one off a 7.3l that would start smoking under a hard load that had a cracked turbo cartride.

 

[gnxtc2]

We just got the job done, pulled the heads and had them pressure tested and machined flat. They Tested fine and only needed .003" to flatten. Truck fired up when we were all done, and ran great for us. Customer calls shortly after picking up the truck and says it's doing same thing, lots of smoke and drinking coolant. We are pretty lost at this point.

.003 is the thickness of a human hair on the head. Where the heads shaved on a CBN, broach or grinded?

Interesting how you're going to handle this ^^^^ with the customer.

Billy T.
[email protected]

 

[lincolnlocker]

major head scratcher here. in to see what is found..

live life full throttle

god bless america and the farmer who feeds your fat ass

 

[CATDiezel]

I would take an oil sample and have it sent off asap... a cracked liner or leaking block should show up in the oil. If not then only other option is turbo.

 

[DZL JIM]

.003 is the thickness of a human hair on the head. Where the heads shaved on a CBN, broach or grinded?

Interesting how you're going to handle this ^^^^ with the customer.

Billy T.
[email protected]

Not sure how they flatten, I will find out more about their process today.
And yeah, I get the fun part of dealing with the customer on this.

major head scratcher here. in to see what is found..

You aren't the only one scratching your head.

We got the truck somewhat back apart. 3 cylinders on the passenger side are soaked, the front cylinder is dry, and the turbo is definitely not the culprit. We are working on removing the head and getting it back to machinist asap to see if it is still a crack that he missed. At this point it's all it can be, any flaw in the block would seem to have very different issues. And I can't believe it's another failed head gasket, if that was the issue the first time.
The thing is the smoke goes away above 10 psi of boost, so we are leading towards crack in head that is "sealed up" when boost climbs (or back pressure climbs).
I'll keep y'all posted.

 

[DZL JIM]

I would take an oil sample and have it sent off asap... a cracked liner or leaking block should show up in the oil. If not then only other option is turbo.

Oil looks great. No coolant whatsoever and clean as when we put it in last week. The truck lost about 2 gallons of coolant and it's obvious it's getting pushed out the pipe and not going into the oil pan.