A cold engine will generate a lot less pressure in the cylinders for two reasons.

The rings seal better at temperature, and the heat from the cylinder walls increases the temperature of the compressed air a bit.

Plus the fact that the valve-clearances are smaller when cold, and affect compression measurements....

And, Cranking will be slightly faster, as there's less drag of thick oil....

Prolly add maybe 50 psi to those 'cold' numbers for a good, hot engine....

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

Where did you take the readings from? Glow plug or injector? Which tester?

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked