Just put my wife's 2002 VW Golf up on stands for an oil change. The car is at HOT operating temp, so I thought I'd grab a beer before pulling the filter.
I pulled the plug, and it's draining fine. Just for extra measure, I removed the filler cap.
A light smoke or steam is coming out the filler cap. Not a lot, but enough, and its been coming out gently for about 60 seconds at least.
Any thoughts?
I know the VW Golf 2.0 is notorious for burning oil... We've had to add oil on numerous occasions.
Sounds like its definitely hot enough... :)
Do you see any gunk in there when you look in at the filler cap? Any milky looking stuff on the dipstick? Any oil slick in the radiator? Smoke out the tailpipe?
No way to tell if there is a problem without more specifics - how often? How many miles before it burns a quart, etc.? How many miles on the engine?
There is a little bit of black gunk on the underside of the oil cap. Like sludge.
Dipstick and tailpipe are very clean, no smoke.
I've always used synthetic since 12000 miles, It has 76000 now. Sometimes it won't burn a drop in the 5000 miles between oil changes. Sometimes I need to add a half quart, sometimes a full quart....
A quart in 1,000 miles is considered normal by most manufacturers, so you are within specs. I have seen some references to sludge buildup with Amsoil. Also some references to less sludge on Mobil 1. YMMV. Could just be a lot of short trips, too.
Its perfectly normal for piston engines to have a little bit of blow-by vapor in the crankcase. With the engine running, the PCV system draws off this vapor and runs it through the intake, burning the unburned hydrocarbons. When you shut it off and pull the cap, the vapor in the crankcase will rise out of the engine. If you run the engine and remove the PCV valve, vapor will continuously waft out of the oil fill hole or PCV valve hole.
Its perfectly normal for piston engines to have a little bit of blow-by vapor in the crankcase. With the engine running, the PCV system draws off this vapor and runs it through the intake, burning the unburned hydrocarbons. When you shut it off and pull the cap, the vapor in the crankcase will rise out of the engine. If you run the engine and remove the PCV valve, vapor will continuously waft out of the oil fill hole or PCV valve hole. _______________________________________________________
And if the oil pan plug is out for draining, the added ventilation will pull external air into the hot crankcase, causing in increase in the upward flow of visible vapor.
Rodan.
That is interesting. Can you correlate this variable oil loss with anything else, like ambient temperature, long highway drives versus city, mountains vs lowlands?
As others have posted, it is not unusual to see vapor emitted when you open the filler cap of a hot engine.
I will say that, because of the improved flow characteristics of the synthetic oils, they are much more prone to leakage. Small gasket leaks that seal fine with petroleum oils will tend to weep a little of the synthetic. Keep doing that for long enough, and you can find yourself down a bit. You'll know from the stains on the driveway, unless your driveway looks like mine and is so stained you can't tell.
--scott
Yeah, Scott, I have had new cars that would "weep" a little from the beginning, and the synthetics had to be the key.
However, if you go through a change interval and sometimes lose nothing and other times lose a quart or so, this makes me wonder what is really happening.
I know you know what I am wondering about. Could be synthetics, but might be something else.
Worn valve guides/seals are probably the likely suspect. High vacuum from idling/backing down can suck it up pretty good. Had a 352 with bad guides that used a quart of oil per tank of gas during my normal city driving. Took it to Yellowstone and back, maybe 3000 miles put in 10-12 tanks of gas and it used less than a quart of oil, because it was seldom under high vacuum. I've also noticed hard acceleration on worn engines burns oil, and suspect it gets by the rings, but that's just my "impression." The worn guides is real measured experience.
--Vic
Could be. I have seen a lot of them that would burp some blue smoke when starting but would then settle down and not really burn large quantities of oil. Slightly worn valve stem to guide dimensions, I think.
Exceptions were some that had crumbling stem seals and those seemed to suck substantial oil all the time.
I think the hard acceleration point is valid. Seems like the oil control rings are the issue more than wear in the cylinder.
I may be way off base on this.
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