Volvo XC70 Burning Oil

arhdc · Post by **arhdc** » 31 Dec 2016, 11:35

Ok, please know that I have searched extensively for clues and information about this but I can not find anywhere where my Volvo pathology is addressed. I am a fairly decent shade tree mechanic that is sadly lacking adequate understanding of Volvo anatomy to figure this out.

I recently purchased a 2004 Volvo XC 70 with a 2.5T engine with 104K miles that is burning oil, approximately one quart per 250 miles. This issue was disclosed before purchase and the previous owner was honest to a fault, so I do not question the information that he has given me. Initial diagnosis of the problem prior to my ownership was a clogged PCV system that has subsequently been replaced by a Volvo specialty shop. It has been reported to me that this briefly reduced oil usage but it was a short lived reprieve. I have receipts for the PCV repair and the car passes a PVC glove test so I do not believe that PCV system blockage is presently an issue. Through all of this the engine has run very well, no detectable drop in performance.

SO this is the odd part, hard right hand turns executed after then engine has been running at least ~90 seconds (no smoke even on a hot engine at initial startup) produce a significant cloud of smoke. Left hand turns produce no visible smoke, hard acceleration produces no smoke, hard braking produces no smoke, turbo boost produces no smoke, engine braking produces no smoke, only hard right hand turns. Hard right hand shifts at speed with zero throttle variation do produce smoke. The amount of smoke is seemingly proportional to the length of the forceful turn. Before it is suggested that it's a matter of viewing angles, smoke from left hand turns would be more visible than smoke from right hand turns. Under normal running conditions when not turning right an odor of oil burning can be detected but it's nothing compared to what follows hard right hand turns. There is no oil in the coolant, there has been no change in coolant levels and no oil dripping externally anywhere.

So here is my question: What type of oil leak would cause this behavior?

Aaron

Post by **vtl** » 31 Dec 2016, 13:34

Stuck piston rings, hardened valve guide seals, worn turbo. If PCV is known to be clogged in past (that indicates the engine is full of sludge) - have a look at piston rings and turbo.

Also switch to a thicker 0W40 oil.

Post by **oragex** » 31 Dec 2016, 16:11

Also check all turbo piping. If the turbo is worn, a turbo is not expensive used and most should be in quite good shape. No leaks around the engine - camshaft seals under the timing belt cover, rear main bearing ?

arhdc · Post by **arhdc** » 31 Dec 2016, 22:27

Thanks for the replys. There are no external oil leaks anywhere that I have been able to find and the engine is super clean externally so leaks of this volume should be easily found. The obvious things that I would look at in any engine are valve guide seals, stuck rings and (in turbo equipped engines) bad turbo seals. I was/am hoping that the smoke generated by right hand turns would be a red flag for someone out there for a Volvo specific failure to help focus the effort at diagnosing this problem rather than trying to work through every possibility. I will check the turbo piping first chance I get and absent any clear direction work through a ring decarbonizing/engine desludging regime.

In the meantime, if anyone has any insight it would be greatly appreciated.

Post by **vtl** » 31 Dec 2016, 22:31

Right turn pushes turbo's impeller to air intake side, that may be a hint. Easy to check by hands, just remove intake pipe.

Post by **abscate** » 01 Jan 2017, 05:04

My gut feel is this is a top end problem with oil pooling on the side in question hitting a bad valve guide seal.

The turbos on these cars are really robust and don't give problems often

zoli_m13 · Post by **zoli_m13** » 05 Jan 2017, 12:53

What oil did you fill into this engine?
My bet: cylinder head renovation ahead.

Post by **jimmy57** » 05 Jan 2017, 20:54

Drive the car through RH turn and get it to smoke profusely and then shut it down and pull spark plugs. If it is turbo it will oil all plugs. If it is valve stem seals or rings it will be selective as to cylinders with heavy oiling of spark plug.

arhdc · Post by **arhdc** » 09 Jan 2017, 09:16

Thanks for the continued reply's. I've been out of town this past week or so and have not had an opportunity to inspect the turbo as of yet. I will update this thread as I learn more and can rule in/out causes.

Post by **JRL** » 09 Jan 2017, 13:31

Do a full and proper SEAFOAM procedure then change to a good synthetic oil