ATTN: Fatmobile; "Oil Out the Dipstick"
Posted: Wed Jun 07, 2006 8:57 am
Searched high and low for your famed posting titled "Oil Out the Dipstick", but found nothing. Can you please post a link?
On the drive back from a long weekend of camping in our 83 Westy with 1.6NA diesel, I noticed the rather sudden appearance of oil flecks covering the rear tailgate and window. One minute, nothing; the next, quite a mess. Popping the engine lid, I saw oil flung everywhere, especially around the belt and pulley area.
There was no loss of power, no overheating, no mingling of coolant and oil, and no evidence of the burning of either. Taking it easy and keeping an eye on the oil level, we limped home at low highway speeds.
After cleaning the engine compartment and firing it up again, I've traced the leak to the dipstick tube, suggesting excessive crankcase pressure. Not a lot, just a slow and steady drip that falls down onto the V-belts and gets flung everywhere. I also found the air filter was all sooted up and partially collapsed onto one of the intake runners inside the airbox. All the rubber bits of the filter were intact but I might to be missing a dime-sized piece of the paper element, presumably sucked into the engine?
I'm getting some blowby from the valve-cover vent hose and from the oil-filler cap, though I don't know how much is acceptable in a diesel, nor how much it has increased over the years. I once owned a very worn-out Datsun that would not allow oil to be added when the engine was running; when you poured oil into the valve cover, the high blowby just blew it all back in your face. The blowby from my VW diesel (106k pampered miles) isn't anywhere near that bad. Replacing the air filter seemed to reduce the drip somewhat but it's still there.
Obviously, all this points to worn rings or valve guides, but what strikes me is how suddenly the leak appeared, suggesting perhaps a BROKEN ring instead (or perhaps a bit of filter paper stuck somewhere)? I changed the oil and filter, so I suppose the next step is to do compression and leakdown tests to get some idea of the general condition, and maybe pinpoint the offending cylinder.
I generally don't like additives and other magic-in-a-bottle, but a respected VW mechanic specializing in the air-cooled engines likes to occasionally run a half-quart of Marvel Mystery Oil in the fuel tank and another in the crankcase for 300 miles, then dump it. He feels this burns off accumulated carbon on the piston heads, valves, and rings, and loosens up other crud in the engine. Instead of the expected thinned-down oil, he drains all manner of tarry black crud out, and claims the internals are visibly cleaner on an engine that has had this treatment a few times.
Any advice to offer?
On the drive back from a long weekend of camping in our 83 Westy with 1.6NA diesel, I noticed the rather sudden appearance of oil flecks covering the rear tailgate and window. One minute, nothing; the next, quite a mess. Popping the engine lid, I saw oil flung everywhere, especially around the belt and pulley area.
There was no loss of power, no overheating, no mingling of coolant and oil, and no evidence of the burning of either. Taking it easy and keeping an eye on the oil level, we limped home at low highway speeds.
After cleaning the engine compartment and firing it up again, I've traced the leak to the dipstick tube, suggesting excessive crankcase pressure. Not a lot, just a slow and steady drip that falls down onto the V-belts and gets flung everywhere. I also found the air filter was all sooted up and partially collapsed onto one of the intake runners inside the airbox. All the rubber bits of the filter were intact but I might to be missing a dime-sized piece of the paper element, presumably sucked into the engine?
I'm getting some blowby from the valve-cover vent hose and from the oil-filler cap, though I don't know how much is acceptable in a diesel, nor how much it has increased over the years. I once owned a very worn-out Datsun that would not allow oil to be added when the engine was running; when you poured oil into the valve cover, the high blowby just blew it all back in your face. The blowby from my VW diesel (106k pampered miles) isn't anywhere near that bad. Replacing the air filter seemed to reduce the drip somewhat but it's still there.
Obviously, all this points to worn rings or valve guides, but what strikes me is how suddenly the leak appeared, suggesting perhaps a BROKEN ring instead (or perhaps a bit of filter paper stuck somewhere)? I changed the oil and filter, so I suppose the next step is to do compression and leakdown tests to get some idea of the general condition, and maybe pinpoint the offending cylinder.
I generally don't like additives and other magic-in-a-bottle, but a respected VW mechanic specializing in the air-cooled engines likes to occasionally run a half-quart of Marvel Mystery Oil in the fuel tank and another in the crankcase for 300 miles, then dump it. He feels this burns off accumulated carbon on the piston heads, valves, and rings, and loosens up other crud in the engine. Instead of the expected thinned-down oil, he drains all manner of tarry black crud out, and claims the internals are visibly cleaner on an engine that has had this treatment a few times.
Any advice to offer?