Oil bombs!

[topgear]

Heres an interesting problem (sort of) for you all to ponder on. This morning i checked the oil level in my 1.6 VDP as i was expecting to travel 200 miles today, it was just above the min on the dipstick, so i put half a litre of fresh oil in. The car was cold at this time i may add! I didnt check the level, but on the way up the motorway there was a sudden smell of burning oil, and a huge plume of blue smoke from the exhaust, lasting for about 2 seconds, before stopping completely.. it did this a few times... but the engine was totally smooth... After checking the level at my destination i found the oil level is now beyond the max line, which is strange, would half a litre really push it up that far? On the way back the car did it a few more times, much to the disgust of a bmw convertable tailgating me! Is this because is overfilled? will i cause damage if i leave it overfilled as apparently it is? ive checked it again, and its still a fair bit beyond the max line.. and how come half a litre filled it up so much? Perhaps i didnt check the level accurately before i topped it up earlier? Either way, oil bombs are actually a lot of fun.. if only i could controll when they are going to happen! :)

Any comments advice, no matter how silly, sarcastic or helpful will be rad gleefully! :D :)

[e692wtt]

How's about this? Your oil filler tube was completely blocked ('mayonnaise' from slow running round town) and the crankcase is 'breathing' via the bottom oil filler seperator only. But at high motorway speeds, the engine needs to dispose of more crankcase gases than just the unblocked pipework can cope with. The oil filler tube is mostly full of oil (from before - or a longer period?) so as the blockage begins to clear the crankcase gases bubble-up through the oil and blow some of the oil into the breather pipes and back to the carburettor, where they pass into the air-fuel mix and into the engine causing blue smoke. Only a bit of the oil gets carried through, the rest is left in the filler pipe or the breather pipes (majority in the former still) and when the engine is stopped your new oil drains into the sump and fills it over the 'max' mark.

To quote Amazon Women On The Moon: "B:censored: lls:censored: it or not? You be the judge!":laugh:

The other other Rich.;)

[topgear]

excellent advice.. cheers mate! :-) Ive never had a problem of mayonaise before, but i have been doing a fair bit of "stuck in traffic" driving lately.. and so this sounds like the problem alright... I'll leave it for a while, then sort it out at the next oil change, around October/November hopefully.

Thanks for your help! "May the blue clouds continue!"

[John]

So someone else knows that great classic film, Amazon women on the moon, tremendous special effects.
It might be an idea to drop a bit of oil out, I don't think it's a good idea to overfill.

[SimonR]

This might seem obvious, but did you check the oil level while the car was parked on level ground each time? I've found that it makes quite a big difference with my S-Series.

With regard to whether or not the oil breather/filler is blocked, this is more than likely as we S-Series owners sadly all too well know :( You'll be able to check by taking the filler cap off and checking down the filler neck and also in the cap itself. You can also disconnect the pipes from the T-Piece that goes from the separator to the carb and filler cap. When my car had problems these pipes were full of cack. My advice is to use Unipart Silver part-synthetic oil - this does not emulsify at all in my experience.

If the sump really is too full I'd undo the sump bolt and let a bit of oil out. Speaking from experienve, quite the last thing you want is to rupture any oil seals. I have done on my current engine and I'm in the precess of replacing it as a result....

Good luck !

Btw, the mayonaise problem is caused by the oil breather system being situated at the front of the engine. The oil vapour is quickly emulsified as it is being hit by cold air comming in to the front of the car as you travel along. I would expect to experience the problem during the colder months and not at all really in the summer.

To give you some idea, I changed the oil and cap (with much better seal) in July 2000 and ended up with ruptured cam/crank seals and gaskets in March 2001, on my birthday! - it took the winter for enough cack to build up.

[e692wtt]

Mine has mayo all year round in the filler tube and breather even in the summer, unless the car gets a good long hot blast (like last friday, see 'events and meetings' thread) upon whence it clears itself. Builds up slowly again.

I swear by Duckhams Oils for producing minimal amounts of mayo - there's no point using anything thinner than Q 20w/50 in my Monty anyway as it just burns...

The other other Rich.:cool:

[Simon]

My old engine used to emit oily breather fumes and gas me whilst I was driving. Boy did it ming. It also used to blow the top of the breather cap off, the bottom of it used to stay locked in the filler tube because the oily fumes caused the O ring seal on the cap to swell and distort. Happy memories. My new engine with the later breathing system doesn't produce creamy sludge, simple as that!

New engine? Its not far off 50,000 miles already!