D5 (2005 on) low compression will not start

[bedfordbjk]

just bought xc90 2006 D5 185 156k miles, drove well for 100 miles although cranked a bit more than expected before starting. Noticed exhaust a bit smokey on start up, indy garage says two injectors dribbling and one passing a brown fluid ? Got three used tested injectors, garage just about to start change and car cut out, will not restart. timing belt ok and timing bang on eventually checked compressions - 70, 70, 120, 180, 150, much lower than expected 400+
Just about to start taking off rocker cover to have a look - any ideas ?
wondering if someone put in mineral oil, with poor injection washed bores and lost compression ?

[Tannaton]

Originally Posted by bedfordbjk

just bought xc90 2006 D5 185 156k miles, drove well for 100 miles although cranked a bit more than expected before starting. Noticed exhaust a bit smokey on start up, indy garage says two injectors dribbling and one passing a brown fluid ? Got three used tested injectors, garage just about to start change and car cut out, will not restart. timing belt ok and timing bang on eventually checked compressions - 70, 70, 120, 180, 150, much lower than expected 400+
Just about to start taking off rocker cover to have a look - any ideas ?
wondering if someone put in mineral oil, with poor injection washed bores and lost compression ?

Really unusual to have low compression on all five cylinders. Even a bad head gasket failure usually only takes out one or two pots.

Using the wrong oil or oil starvation usually damages the bottom end first but there are no hard rules for this. The problem with mineral oil is that it decomposes and creates solid deposits when hot so and that is most likely to happen in the turbo charger.

The D5's can suffer from leaking injectors and this can cause smoke on start-up and longer cranking before firing but this would not affect the compression. There is a simple leak-back test you can do (documented on YouTube) which will confirm this.

I do wonder if you have been sold a pup with a damaged engine and they've done something to it to make it temporarily run well? I can't think what though....

If compression is bad then then usually it needs to be stripped to investigate or cut your losses with a replacement engine?

[bedfordbjk]

Thanks Tannaton
Latest is we squirted some fully synthetic oil down the glow plug holes turned it over to seal the bores and it started. I guess unburnt diesel had washed the bores. Now concentrating on the injectors and we will restart with a fresh charge of fully synthetic oil and see how it runs, then recheck the compressions.

I always wanted a pup but one with a waggily tale.
Sold by an ebayer with 233 (100%) positive feedback who assured me "drives great in all round good condition" in his advert and looked me in the eye and said there was no problems with the car. Picked it up at dusk when it was hot and I didn't notice smokey exhaust. I have always been lucky with ebay cars, I guess I was due a fall..