Noticed if volvo is left idling for 7-10 it starts burning oil and will not stop until its brought up to speed again and kept there for a while (i can't see the smoke spew out).

Currently on 10W-30 Synthetic Mobil 1

Thinking about giving it a Restore treatment, any opinions?

http://www.ametech.co.uk/shopping/default.asp

Mobil1 has so much detergent properties in it that it is doubtful that any snake oil cleaner is going to do anything more. The only ones I would use are Marvel Mystery Oil and SeaFoam. Again, cleaning is not needed if you have been running synthetic.

Under what circumstances do you need to idle for more than 7 minutes? Idling tends to be a sludge factor with any car, even if the engine is hot.

May be time to clean out your oil seperator under the intake manifold and the flame trap and pc fitting on the throttle body.

Is it a turbo?

yeps it be a turbo

I know my older volvo's burn oil in a similar fashion because of worn valve guides/seals. (B20 engines) But not generally while idling, though that could be differances in the cyl head. Not sure how the 5 cyl. head is constructed. I do know that the turbo is going bad on my gf's 850. If it is left to idle for a longish period of time oil collects in the exhaust, and it leaves a hefty smokescreen when it pulls out. Thankfully, with the replacement of the PNP switch, it no longer needs to idle for 20-30 minutes!

-Nick

I sure as hell would NOT buy some snake oil for $20 + $20 shipping!! I wonder what it fills the 'microscopic' cracks with, metal or 30 weight oil? What does it do to the rest of the block?
You may have a valve seat wear problem, which will not be fixed by coating the block with goop.

Klaus
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1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

even if it means better engine compression afterwards?

is that related to oil burning?

and why does it need to idle for a while before it starts burning oil in exhaust.

Hi footrest. If you exhaust starts smoking after 10 minutes of idling, there is a good reason for it. At 950-1000 rmp, there is insufficient oil pressure to spray the inside of the cylinder walls with oil and oil is not being splashed on the inside of the block by the rotating crankshaft. The cylinder walls get overheated, as do the rings, because they are scraping bare metal. The pressure of the oil vapors are escaping past the rings and burning at a rapid rate.
When you finally drive and get the engine over 2000rpm, oil gets sprayed on the cylinder walls and the rings get lubricated again and create a tight seal. The oil smoke goes away :)
You will need to replace the oil separator and replace/clean the vacuum lines to the intake part of the turbo. That is close to the firewall/turbo. If you don't do that, you will start seeing a rear main seal leak due to the sludge buildup.
There is no reason to let the car idle, except when scraping frost or snow when it is above 30F. Seat heaters work wonders.

Klaus
--
1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

Klaus,

I'm not sure I am buying this.

When these cars were new, you could idle them seven days to Sunday and never get a puff of blue smoke. In fact, just about every car, regardless of manufacture, could do this.

Yes, there is probably a decrease in lubrication at idle but I think the basic problem is that these cars are susceptible to sludging oil deposits and one of the areas on these 850s that gets affected is the oil control ring.

When I took apart my engine I found lots of gunky deposits in the oil control ring land, and some commensurate deposits in the compression ring lands.

Now, when the oil trap and associated ventilation system is clogged, this problem is pretty obvious. But even when you clean those out, Your rings are still gunked-up.

I'm not a fan of the Italian tune-up being the solution to unexplainable problems.

Let me know what you think.

Ken

Ken,

The bane of the 5 cylinder, turbo charged engine, is sludge buildup. This is caused by low rmps over many miles and years. When most of the car's life is spent commuting in the suburbs, the tach seldom goes over 2K. BMW has always reccomended driving in excess of 2500 rpm to keep the oil splashing and bathing the cylinder walls.
I agree that Volvos have an engine that will build up sludge at the oil control rings and piston rings. And revving the engine on a regular basis will not necessarily keep the sludge from forming. Changing the oil frequently and using synthetic will help, but idling for extended periods of time will cause sludge to form faster.
I only suggest revving the engine at least once or twice a week to help keep sludge from forming at the piston oilers, and trying to keep the revs above 2000 rpm.
It doesn't take a rocket scientist to understand why prolonged idling is bad for an engine, especially when it is 10 years old. I am still trying to understand why anyone would want to let a car idle for so long. I just turn on the seat heater in the winter and roll down the windows in the summer and drive!

Klaus
--
1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

Prolonged idling is deadly to a gasoline engine because of emissions and lack of lubricant. Policemen and maybe taxi drivers are about the only people who I can think need to idle for minutes, and police change their cars on a regular basis.

In the 1970s, I recall that many people had a goofy belief that it took more gasoline to start the engine than to leave it idling, so they went into the store or restaurant and left the car out in the parking lot with the engine on. You still see that here in the south in mid-summer, but here the owners are keeping the AC on so the car will stay cool. Another demonstration that gasoline is an incredibly cheap commodity here in the USA.

I'm not one to let my 850turbo idle except for when:

- stuck at the back of a parade and moving at snail's pace
- left the car in the hands of an emissions attendant who left it switched on whilst i was settling the bill

In the first case i knew i smelt oil but there were lots of cars around and too many other things to look at. In the second case i wondered what if he had tested the car for emissions after having left it idle for a that time.

I'll get the turbo intake lines and oil separator checked in a couple of months.

a friend of mine who sells cars , told me turbos after running need time to cool befoe turning off the car. 30 sec to 60 sec... at idel.
hope this helps ?

whats a good way to remove the sluge build up ?

The Volvo engines are not known for piston ring degredation. It would be the last thing to consider. No European engine is made to idle for 10 minutes after a cold start, it is bad for oil circulation and creates havoc in the way of sludge buildup, regarddless of oil type. This is worsened by the turbo in the exhaust stream and the piston oilers inside the block.
Check your vacuum lines where the line enters the turbo air intake, it is probably almost clogged. It will be a good idea to clean/replace the oil seperator as well.

Klaus
--
1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi