2007.5 lmm egr cooler?

Dmax2005

New member
Jun 9, 2012
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tehachapi, CA
First time on here. I am working on a 2007.5 with a LMM Duramax. Lots of pressure keeps building in cooling system and low coolant light with come on after about 1 week of driving due to the coolant is being sucked down in the bottle. no external leaks. As soon as you remove the cap alot of pressure blows out and bottle fills back up. I removed all glow plugs to see if any fluid in cylinders and all were dry. Possable EGR Cooler leaking? Just wanted to get some feed back before I start ripping it apart and spending money. Thanks.
 

LWATSON

future trans limpers
Jul 30, 2008
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Scotland Neck NC
I'm not sure. I had a friend with an 05 that would use coolant and the radiator hose stayed hard all the time. He drove it for a year like this until he bumped up the power one day. It blew a hose somewhere across the top of the engine from preasure and then discovered the blown head gasket.
 

JoshH

Daggum farm truck
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Feb 14, 2007
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Texas!!!
Sure sounded like head gaskets to me. I'm glad you got out cheap.
 

Banders

New member
Feb 23, 2015
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Your EGR cooler problem matches mine exactly. I have a 2007.5 LMM. I do not see any steam exiting the tailpipe. Did you see such in your experience with this? Nor do I smell any coolant at the tailpipe. The lost coolant must be being forced out through the exhaust. The local dealer tech is thinking head gasket but I agree with you, the amount being lost is escaping very slowly and i have no residual pressure at the upper radiator hose after engine cool down.