2003 2500HD coolant leak, mechanic can't find it...

[Joebada]

Hi,

I have a 2003 Silverado 2500HD with a slow coolant leak and my mechanic can't find where it's coming from - and his shop is widely regarded as the best heating/cooling outfit around.

He did a pressure test, which revealed nothing. He told me he checked the water pump and the intake manifold (which I understand are commonly a problem with this particular model) and found no leak.

He said he found evidence of the leak along the oil pan, but cannot get it to leak.

Any ideas?

Thank you in advance,
Joe

 

[white044x4]

I HAVE AN 04 1500 5.3 SLOW COOLANT LEAK, CANT FIND IT ! Ive been checking the net and found that chevy has a tsb [service bulletin] on castech cylinder heads cast #706 they crack!! i ran out and checked my cast # [infront ofvalve cover ] #862 feel a little better but still wondering if my 04 has cracked heads or something else. check net [CASTECH CYLINDER HEAD FAILURE] Has anyone heard of this ???

 

[steakman]

Joe..it would be good if you filled out a "signature" with yr, make, model, engine type - mileage etc...makes it easier to figure out things no.? and to help us help you out.

if its a duramax...my thoughts would possibly be Head Gaskets..at the rear of the motor. Or a line that has developed a leak but drips in such a spot as to evaporate before it hits the ground.

Rgds,

Theo