compression

[carbonfiber dream]

got a question 4 u guys.... i did a compression test on my car (99 e36 m3 with 141,192 miles) and it read 180 on cylinders 1-4 185 on 5 and 180 on 6. is this good? im not sure what it should be considering the age and milage. any help would be cool.

[justin1180]

that is a totally acceptable range.

[Jack Dabsy]

Nice one Justin.... Well within 10% so should be Fine... But why did you have the cylinder compressions tested?

[carbonfiber dream]

had them tested just to get an idea of the condition of the engine considering i beat the hell out of it. ran it real low on oil 2 times or so and didnt realize it till i herd valves tickin.

[Jack Dabsy]

German engines are probably the best in the world...
For you to run it TWICE with low oil just suggests a rocker/sump gasket change at this time as you must have a leak!
Compression values will always deteriorate as the car gets older, but to keep these values within 10% of each other tells me that the cylinder head "Should" be ok...
I say this because when an head gasket or even cylinder head problem occurs, it generally affects only one cylinder... Call it it's weakest link if you like...
So to summarise, if one cylinder had a dramatically low compression then the head/gasket may have failed...
Symptoms include - oil in coolant and vice versa - water spurting from coolant expansion tank - milky oil filler cap...
Hope this helps... DAZ

[carbonfiber dream]

thanks bro