Engine/Transmission (1994 - 1998) Compression Test

[CESpitz]

I am new at this so please understand if I make a few blunders

I am working on a 95 Dodge Cummins that I just got it is going to need a lot



of work. I was in hopes someone can tell me what the compression should



be on a good motor the engine has obout 195,000 mi. on it and I am going to do a





compression test on it and I would like to have some idea of what it should be. I



have heard that Cummins uses something like a leak down test . I have barrowed



a compression tester so I would prefer to do that for now. Any help would be great.



HAPPY NEWYEAR AND THANK YOU

 

[Bob4x4]

400psi is good it can be less and still be ok Variation hole to hole is more important

 

[CESpitz]

Thanks Bob4x4 that helps a lot now I Have a base line

 

[KBurgoyne]

dont use oil if you find a low cylinder.

 

[CESpitz]

dont use oil if you find a low cylinder.

Thanks for the help

 

[liftedlpg]

So how do u test a 12 valve? No glow plug or spark plug hole? Ive tested gaso before

 

[CharlieFoxtrot]

You take the injectors out. A gasser compression tester won't work -- not enough psi capacity.

 

[Bob4x4]

So how do u test a 12 valve? No glow plug or spark plug hole? Ive tested gaso before

You will need an adapter that will fit just l ike the fuel injector you will have to remove

 

[Destroked 450]

My SnapOn diesel compression tester goes the 600 psi, adapters don't come with the gauge, you buy them individually.
I've used it two times in five years, wasn't really worth buying.

 

[liftedlpg]

Thanks guys. My old 12 valve feed truck starts easy but smokes profusely for 10 seconds. Bought it very used. My 24 v doesnt smoke. The 12 v heater core had melted away plastic in previous life so i think the engine has been seriously overheated