air bubbles in cooling
 

Hi Everyone
2cd post,, 1990 dodge 2500 4wd 5spd,,getting air bubbles in my coolant/radiator ,, but doesn't seem to have any oil residue in the coolant and not getting any water/moisture in the oil,,has about 150k and runs like a top,, please tell me its not shot or cracked cylinder ,, thanks
Tony[duhhh]

Sounds to me like head gasket problems. Even if it doesn't smell like it's burning coolant or creating white smoke remember that diesels run extreme compression so it's more likely for air bubbles to be pushed into the cooling system than burning coolant. So I'd say head gasket issues.

Thats what I was hoping and figured,, but someone scared me with might be pinholes in cylinder walls,, thats why I ran it by you all,, any way I can test for either for sure before I tear it down???
Thanks Tony[duhhh]

I agree with head gasket but it should be over heating too.

pinholes in cylinder walls give you coolant in the oil. You can stick a camera in the oil drain hole, pressurize the cooling system and bar over the engine to watch for leaks.

Cylinder leakage test is the only way to be sure. I would run the test before I ripped the head off. I also read that the non ic engines ate more prone to cracked heads, but also read guys run them even with cracks with no problems. I have no personal experience with those engines, just what I read.

Head-gasket. :(

^^^^^^^^^^^^:(

it is overheating ,,I should have said that,, how do you perform cylinder leakage test,, can it be done at home or do I have to take it to cummins? I have a fair amount of tools such as a diesel engine compression tester, air compressor ?? gauges ,,
Thanks Tony[duhhh]

You have a fitting that screws in each injector hole and bring the pressure up to what the specs say and see what you lose in the specified time. With a diesel you cant just use a air compressor, you need a compressed inert gas to get up to the 450-500psi.

If you have a coolant pressure tester try running a few cycles and seeing how long it takes to lose pressure and if there is white smoke when you start it up. Even if the coolant hold pressures it doesn't mean anything. Coolant is around 15psi and cylinder is around 500psi so it will still push only one way.

I would say its 99.9% certain its a head gasket

Same thing happened to me last year. I was convinced it was a head gasket. I got a very nice call from the shop telling me it was just the water pump. Easy fix.