300TDI Compression Test Results - Worn Piston Rings???

Morning..

On Sunday I covered about 160/180 miles in my Discovery 1 on and off road. Before setting off I topped up the engine oil level to Max and was surprised to see it was frighteningly low.

During the day one of the lads in a following vehicle commented that my disco was blue smoking quite badly.

On Monday morning I checked the oil level again and found it has gone from Max on the dipstick to below minimum. The disco drops a small amount of oil but does not leak from the rocker cover gasket and the engine is generally quite dry.

I carried out a compression test yesterday morning on a cold engine as it has not moved for 2 days and attained the following results.

Cyl 1 - 270psi cyl 2,3 and 4 280psi.

I appreciate these are down on the manual values of 348psi but they are all quite even. Does this mean all my piston rings have worn evenly and need replacing or does the problem lie elsewhere?? Are the manual values those expected from an average engine or a new/rebuilt engine?

I must point out that I replaced the head gasket a month or so ago more for piece of mind than necessity. Whilst the head was off I reground the valves, cleaned up the head refitted with an elring gasket, new valve stem seals and new bolts and reset valve clearances.

Any pointers as the where my engine oil is going greatly appreciated.

Thanks in advance.

Turbo?

What mileage is on the car?

128k on the clock.

M8CPK said:

128k on the clock.

Click to expand...

That's nothing for a 300, check for play in the turbo.

warrior said:

That's nothing for a 300, check for play in the turbo.

Click to expand...

Absolutely,and did you fit the right head gasket or just go for the thickest one ?

Yer i would take the hose off the compresser and check for oil. Compression checks should always be done on a warm engine as well.

I've had a quick look at the turbo. I removed the pipes and ran the engine. No oil came out and seemed to be blowing well. I'll check for play in the impeller.

Fitted a 3 hole gasket which is the same as what came off.

M8CPK said:

Fitted a 3 hole gasket which is the same as what came off.

Click to expand...

Trouble is that is the thickest gasket,many just wack one of those on thinking its any easy quick way.If you measure the piston protusions you might find a thinner gasket would be correct - that way you get the right bump clearance and better compression readings.Along with better starting and more power.

does it breathe heavy with filler cap off and running ,drop hose of turbo to intercooler run engine does oil drip out of turbo ,is hose very oily or just wet

It has no problem starting and seems to have plenty of power. I ran the engine with the hose off the turbo and no sign of any oil. Bit of a mystery. All I can think is piston rings at the mo but not really a winter job!!

If it starts fine they its not the rings or at least they are not bad enough to need changing. It could still be the turbo but the oil couild be going out the turbine side and into the exhaust. Was there any oil in the hose you took off? try taking the bottom intercooler one off and see if any is in there.

It could be valve stem oil seals. I'd be extremely doubtful of piston rings being worn at that mileage.

Also was it a genuine/good quality or cheap head gasket as it could be a breech from an oil gallery to one if the cylinders.

Mark

id say valve stem seals. it obviously hasnt been loosing oil for long if you were supprised by the lack of oil. does it smoke under acceleration or overrun if its overrun your inlet valves seals are leaking

Also if you get a bigger puff of blue smoke in the mornings it can be because oil seeps through the seals overnight