I did my first compression test today and these are the numbers adjusted for the higher altitude where I live, about 5300 ft. The car is an 84 300D with almost 141k miles on it.

From cylinder 1 to 5 in PSI:
424
400
400
412
376

According to the shop manual, these numbers are right in the "normal" compression range, but why is cylinder 5 so low and 1 so high?

Thanks.

How do you mean you adjusted for altitude?

__________________

1998 E300D, 287k, barely broken in.

You valves might need adjusting. Tight valves cause low compression.

__________________

Not that that is really low. Mine are all in the range of your low one.

Edit: just saw that you adjusted the #s. Please post your actual readings. Compression gauges give a reading of gauge pressure (pressure relative to the surrounding atmosphere) and do not need to be corrected in any way.

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

The numbers from the guage are as follows:
350, 330, 330, 340, 310

However, in order to compare my numbers to the FSM, I need to adjust them because I live at a significantly higher altitude than sea level. 24-30 bar (348-435 PSI) is the normal range listed in the FSM. Compression will naturally be less where I live, because the air is less dense than at sea level. In order to compare apples to apples, the numbers must be adjusted for elevation.

__________________
cbjukraine
'84 300D