High pressure in coolant system???

Thanks...well the cups were done last week in South Carolina, two completely different tests were done on the compressor in Toronto and the compressor is fine...which leaves the head gasket.
I took it to Volvo this morning in Ottawa and they will test again, but if all else fails, I've told them to go ahead and do the head.

 

Why cant it be the head gasket on a D12?

 

I know this is only a temporary solution however if your out in the middle of know where and can't get it seen to try loosening the radiator cap this reduces pressure and stops any water leaks at least till you can get to the nearest mechanic.

 

I had the exact same problem last week on my d12, I replaced the cups, checked the compressor, and sent it in today to have the head gasket or head done.....I cant think of anything else to do. Hopefully its just the gasket but if its the head, so be it.

 

when I had the problem the cups passed all the test as did the air compressor.
I had then change the cups. 3 were leaking.... remember they passed all the test
2 weeks later the air dryer went out so I had it bypassed till I could get to a dealer. so for 3 days I was draining the air tanks every 3-4 hr's after 2 days I started to see milky spray when I would drain the tanks.... had sealer replace the compressor and the bad air dryer.... that was 2 years ago.

every dealer I have talked to has said they have never seen a d12d blow a head gasket....

 

Well mine has, they pulled the head yesterday and there are obvious signs the gasket has let go, they sent the head out also to be tested. When I think of all the trouble this has caused me. I suspected it was the head gasket from the very beginning, but people who didn't own a D12 kept telling me it couldn't be a head gasket. I was told from day one from a dealer and master mechanic from Pare Volvo in Quebec City. Michael, it's a head gasket or head. Anyway...thanks to you all for the advice. Happy Trucking.

 

So was radiator cap replaced?

 

I believe leaking egr cooler can also cause high pressure and soot in cooling system .
Isn't the EGR flow presure higher than coolant presure during normal operation?

 

EGR flow pressure may only be slightly higher than cooling system pressure. The volume of area that exhaust has to flow through the cooler, the fact that it goes right into the intake and since gas can compress and liquid can't, the path of least resistance is not through a hairline crack in the EGR cooler coolant tube.