Smoke on very steep downhill (1.9 dg)

[amazingdave]

Does anyone else burn oil on very steep downhill grades? like 1 in 3 or 1 in 4?

Both of my recent vans did/ do it on a particularly long and extremely steep hill near llanrwst.... doesn't use that much oil otherwise maybe 1 litre in a 1000- 1500 miles at most...

Is it cos they're flat fours and the oil sloshes up against the piston at extreme angles with engine braking sucking a bit in?

Dave

[Fritz]

I sympathise with you as this was one reason why I decided to have my DG motor looked at. I always suspected a valve guide fault but could never be sure coz during general running about it was fine but put the engine under any load it would start to use oil. It became obvious more so on the 'overrun' with ploomes of blue smoke if for example we decided to have a run out up the lakes when we used to mop oil rather than burn it.

My advice to you is have the inlet valve guides checked and replaced if the motor has no other issues like bad starting or low compression.

Regards

Fritz,,,,,,,,,,,,

[jaylo264]

we get the same , only on really steep bits , had it for years , engine is ok but compression reads low ,all 4 , unsure whether this is related to smoke really -- i had thought it was simply a trait of wasserboxers .

jaylo

[Red Westie]

Now I'm not sure of the layout on these flat 4's but if that were any other engine I would say straight away that your description exactly describes worn/split/cracked/hardened valve stem oil seals.
The test we used to do in order to diagnose stem seals was to get the vehicle in fourth, give it some revs then release the throttle and let the engine slow the car down for 10-15 seconds. re-apply the throttle. Then you see a big puff of oil smoke (you need a long fast road)
What happens is the engine 'over run' creates a vacuum which results in the oil being sucked down the valve stems.
Valve stem seals are extremely common on other VAG engines of this era just not sure about wasserboxers.
Martin

[Red Westie]

Now I'm not sure of the layout on these flat 4's but if that were any other engine I would say straight away that your description exactly describes worn/split/cracked/hardened valve stem oil seals.
The test we used to do in order to diagnose stem seals was to get the vehicle in fourth, give it some revs then release the throttle and let the engine slow the car down for 10-15 seconds. re-apply the throttle. Then you see a big puff of oil smoke (you need a long fast road)
What happens is the engine 'over run' creates a vacuum which results in the oil being sucked down the valve stems.
Valve stem seals are extremely common on other VAG engines of this era just not sure about wasserboxers as I seem to remember that some older air cooled stuff didn't fit them?
Martin

[steve8090]

Martin

The flat 4 engine does not use valve stem seals it relies on a good seal down the phos/bronze guide, they are fed up the pushrod tubes to lubricate the rocker gear then it falls away and back down the tubes.

Like Fritz says get the guides checked

[toomanytoys]

I think.... Piston ring and bore wear...
My syncro puffs smoke from a cold start and on long downhill sections..
oil creaps past the rings overnight... its tired and will be replaced soon...