Engine: 3.2: XC90 Misfire

[seandodwell]

If it's piston/ring related, (doubtful) you would have clouds of billowing smoke. I pulled the injectors and got our works cheap scope camera down into each intake chamber and also down the spark plug hole(no holes there!), piton was fine, valve edge looks burnt on 6, so it must be valve related(Compression test also 0 on Cyl 6).

See attached images most looked very clean I was surprised by how clean the intake chamber was generally, if you look you can just see the burnt valve edge showing signs of blacking up.(second image)

might be cheaper to buy on of these and see for yourself, good luck. Planning on stripping down the head next weekend. I'm also looking for options on rebuild costs.
I'll keep you posted.


https://www.amazon.co.uk/Endoscopic-...zcF9hdGY&psc=1

[ommony]

After much deliberation, and considering my engine has 260,000 miles on it, I couldn't justify repairing the head and putting it back on such a high mileage engine. I also couldn't find a garage locally that wanted to deal with it anyways.
What I did find was a good low mileage complete enginge, and a garage willing swap it in for me at a reasonable rate, so that's the route I'm going to take. Bit of a gamble with the second-hand enginge, but not any more than the gamble of continuing with the high mileage one. Fingers crossed I wont regret it, but at any rate, just wanted to let you know that I'm not going down the head removal/repair route. Best of luck to you!

[seandodwell]

Thanks Ommony,

Was that the 89k mile one on ebay?

I've ordered the camshaft tools, gaskets new head set & Cam shaft bolts, chain and tensioner, so no going back.I'll post here progress and you can see if I fly or fail...!

Strip down starts this weekend.

Good luck with the new engine.

[ommony]

Yeah, that's the one. I know the seller having bought many Saab and Volvo parts off them over the years, and was able to verify the mileage and check the MOT history of the car, etc. Seems like a good find, but we'll see.
Again, best of luck with yours. I'm very curious to see what you find when you take it apart and how the repair process goes, etc.

[seandodwell]

Originally Posted by seandodwell

This is the full chain kit, I'm sure there are others, if any one knows of any, or have any experience with any, can they let me know. Thx.

https://www.rendcarparts.com/parts-f...82/RD30759065S

So an update, head removed after a couple of evenings spent bent over the bonnet!!

All went well apart from the heat shield bolt not giving up so having to remove the manifold bolts through the gap left by bending the heat shield up out of the way, Manifold bolts all good except the last one typically decided to go soft on me an round off, eventually got it off with a cheap right angle six sided box spanner. Still eventually got it all off, and lo and behold burnt valve worst I've seen no wonder there was no compression. See photos, next step is transport down to the nice people in PAR Cornwall Autotec, who will make my head like new.!! I have a quick question for the group is it worth looking at replacing piston rings whilst engine is still in the car, is this hard? the cylinder bores look good, no undue scoring just a good patina. Any thoughts 190k miles but running great till the burnt valve..?

[ommony]

Oh wow! Really cooked. How'd the other cylinders look? Do they seem on their way out or was it just the one that failed? Interesting that it was cyilnder 6 on both of our engines. Also curious why mine lasted so much longer than yours (70k miles more). My engine has been on LPG since about 100k, which should make valve problems more likely, not less, but I have been running a simple Flashlube valvesaver top-end lubrication system that whole time -- I wonder if that actually made the difference.
I don't have a definitive answer regarding piston rings, but if everything looks good, and compression was good on the other cylinders, I would be tempted to leave well enough alone. I don't imagine that the sump can be easily removed without at least lifting the engine a bit, if not pulling it completely? Can't remember exactly what it looks like under there, but it's a big/long engine and unlikely to be straight forward to get the sump off, remove main caps, etc, to get the pistons out. But I'm just guessing.

[seandodwell]

Thanks Ommony, yes properly burnt, just that one valve bizarre, but hopefully the refurbished head will look like new it's gone down to Cornwall now via a mate and my brother. I'll post photos on its' return. Most of the other bits have now arrived, quite a list I find having stripped it all down, Alternator pulley was seized, as was aux pulley, and I'm replacing water pump, the originals not to old 30K maybe but while it's all apart I might as well, I do not want to work on this engine again anytime soon!! Still not sure about the piston rings, the other 5 cylinders were at about 150lb compression when I tested them. I'm checking VIDA now to see what they should be. Any comments suggestions welcomed.

[seandodwell]

Still looking for compatible after market ring sets, Volvo's are £45 per cylinder !!! that' 6 sets... I have an engine rebuild co looking for me. and another supplier sending me compatible sized BMW ones to check against an original set. Any thoughts??

[TruckbusUK]

Have you checked any of the Mahle dealers for 3.2 (apologies not the T6) ring sets .... sure they will be cheaper!