200tdi compression test

[ian_s]

I've been having problems with my tdi for a while now when cold, and before i whip the head off to check the headgasket/bores/valves i am going to do a compression test

i've got hold of a diesel tester, and i checked it quickly last night on number 1 cylinder so i know it works, but what i want to know is what sort of pressures should i be getting, and also whats the best way to do it?

reading the haynes book of lies, it says that landrover dont give a minimum pressure, they only give a maximum difference of 5 bar between the highest and lowest.

on no1 cylinder (when cold) i got 24 bar.

this is how i plan to do it:

1) get the engine warm, taking it for a drive

2) remove all 4 injectors, and remove the cable off the injector pump solenoid

3) check each cylinder in turn, noting the results

after that, i was thinking of putting some oil down the bores and checking again, is this a good idea? the haynes book says not, as the oil will probably just pool in the top of the pistons.

thanks

Ian

[white90]

Here's a 300TDI "how to"

[ian_s]

thanks, so 24 bar on no1 is looking ok

now to do the rest

[ian_s]

update:

done the compression test:

no1 = 385 PSI

no2 = 380 PSI

no3 = 385 PSI

no4 = 345 PSI

4 is lower than the others, but less than 3 bar down on the others so still within landrovers stated limits

[TD5 power]

hi

i would have expected all the readings to be fairly similar like 1,2,3 so there may be a problem with no 4, have you tried adjusting the tappet clearances and then re doing the test before its stripped down. if its sill the same then i would be looking at the valves and their seats rather than rings unless it's burning oil.

Putting a small amount of oil (tea spoon) in the bore before doing the test is a recognized method you will get a higher readings and if you get the same results as before its most likely to be the valves as the oil helps to seal the rings.

the only other test you can do is a cylinder leakage test which involves pressurizing the cylinder using an airline with gauge attached then listen in the intake and exhaust manifolds if you can hear air escaping its the valves if you listen to the crankcase breather and can hear air escaping the piston rings are leaking. A small amount is expected but if you compare for the four cylinders it will be obvious if one has a fault.

hope this is of some help

Matt

[ian_s]

i think no4 was due to my battery starting to die

it was very lazy starting this morning when i tried to move it. the battery is now on charge

i am going to redo the test tomorrow, but doing no4 first.