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Message: [QUOTE="sonic blue l, post: 1070076, member: 5185"] A relative compression test and relative power balance are just that, relative to one another. So if the cylinders are worn evenly a relative compression test will pass. If all injectors are contributing the same, they will show even. Now max spec of crankcase pressure is 10" h2o. Next step is to verify if it's a base engine concern, which would be a manual compression test. Now if that passes then you isolate the turbos, aka run truck so there is no exhaust pressure teaching the turbos. As if you have bad turbo seals then the exhaust pressure will drive crankcase pressure up. Now let's say you have 20" h2o, run the truck with turbos isolated and still have 10" h2o. Well now you had high crankcase pressure which caused the turbo seals to fail in the first place . So bottom line is proper diag does not just mean throw turbos on it as you have to determine why the turbo seals failed in the first place. Problem is, to do proper diag is not cheap. I actually jus worked on a truck with a similar situation. 20" h2o, manual compression down some, but still aceptable. Isolate turbos and crankcase pressure dropped to 10". Authorized to remove valve covers and worn rocker arms. Vehicle was not well maintained so customer decided to have truck reassembled and truck to auction. (Rocker arms can go plenty of miles and hrs without wear if the truck is properly maintained, even with 100% emission components intact) [/QUOTE]

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