Benzmac,
My 75 240 is overheating and has a loud knocking noise, which is above a normal diesel engine knock. Adjusted the valves then checked the compression. My readings were: 1-200psi 2-198psi 3-198psi 4-90psi, poured a little oil in #4 cylinder and tested compression again which read 140psi. Do you think the gasket might be bad? Or the valves might be burned? What things should I look for when I do visual inspection of the head gasket once it has been removed from the engine? Just removed the cylinder head and found lots of carbon deposits on it and on top of the pistons. Would a crack on the head be easily spotted? Haven't found one so far. What should I do next?
Thank you in advance for your asistance.
Gilbert
75 240D 190Kmi
84 300SD 273Kmi

What I would do at this point is a cylinder leak test. Take off the valve cover and turn the engine so that the suspect cylinder has both valves closed. Now You will have to remove the glow plug and connect a fitting to shop air. See where the air comes out...This is your weak link.
Good luck

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
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