Engine: B5244: one thing that puzzles me... slightly.

[ThomasG]

Originally Posted by ASt85

I don't think the type or viscosity of the oil would make any difference because they all get diluted by petrol or diesel during the warm up period in higher mileage engines.

My V70 has about 210K miles on it, I try to let it run for at least 3 minutes if I move it off the drive because of the problems I had with the 850 if I let it run for less than that. On one occasion I could only get the compression back by pouring about 50mls of engine oil into each pot via the spark plug holes............really smokey start-up, but it did start on the first if lengthy cranking after having repeatedly failed to start after being turned off after less than a minutes running.

It is a common problem found in larger/older engines, particularly older Jaguars & etc.

What I was thinking was a bit like..

"If specified oil gets mixed with petrol, it gets thinner, therefore not really doing the job properly. But if thicker oil gets mixed with petrol (and therefore get thinner too) it might, just might land within designed spec?"

I'm aware that the chances are somewhat slim on this, but is it actually a bad idea to put something different in on next oil change (spring)?

[ASt85]

Originally Posted by ThomasG

What I was thinking was a bit like..

"If specified oil gets mixed with petrol, it gets thinner, therefore not really doing the job properly. But if thicker oil gets mixed with petrol (and therefore get thinner too) it might, just might land within designed spec?"

I'm aware that the chances are somewhat slim on this, but is it actually a bad idea to put something different in on next oil change (spring)?

That would seem to make sense but the modern synthetic oils will still have reasonable lubrication capabilities even when diluted due to the various additives used. If you use a heavier oil, the start up lubrication is reduced since it doesn't flow as well - you will still get increased wear but for a longer period of running as it takes longer for the oil to flows easily.

Originally Posted by oragex

Old PCV can also take some oil

I hadn't thought of that but it would make sense.

[VroomVroomClonk]

Have you checked to see if the oil is leaking out?
I still haven't worked out why mine has the occasional but very heavy oil leak that I raised here https://www.volvoforums.org.uk/showthread.php?t=281231

[ASt85]

Originally Posted by VroomVroomClonk

Have you checked to see if the oil is leaking out?
I still haven't worked out why mine has the occasional but very heavy oil leak that I raised here https://www.volvoforums.org.uk/showthread.php?t=281231

I've read your post at https://www.volvoforums.org.uk/showthread.php?t=281231

From your tagline I assume yours is a T5 - which has a turbo - I'm sure I've read something about the intercoolers failing or cracking in these models and then intermittently leaking large quantities of oil which gets sprayed back over the underside of the car.

However, it could be that the oil seals on the turbo have failed but I'd have thought you would have seen smoke from the exhaust