Driven with Engine cap open

[Luky]

A friend of mine topped up engine oil in his TSI and forgot to put the cap back on and drove around for approx. 20 miles before realizing. What could be issues resulting from this, I could see a little dust around the cap area. Does one need to flush out the engine oil (in case it is contaminated)? What other corrective actions should be taken?

[donovan]

20miles with no cap? are you sure it was that much car would have had almost no power and would of felt flat due to no compression.

[m0bov]

your "friend" should be ok. the filler cap plays no part in compression.

[Luky]

your "friend" should be ok. the filler cap plays no part in compression.

Just to make sure we are talking about the same filler cap I have attached a pic.

Uploaded with ImageShack.us

[Luky]

Are there any issues in terms of dust going inside, as it was drive for 20 miles after the incident.

[Antimus]

Are there any issues in terms of dust going inside, as it was drive for 20 miles after the incident.

I'd say negligible. I once drove 50 miles from Lands End back to my camp site (Hilly, bendy, ragged the thing to death) without the oil filler cap, oil light came on as I pulled into the camp site. Sure it wasn't a brand new engine (at the time) but all I got from the local garage was some good-natured ribbing, they said it wouldn't cause an issue, I would assume the same situation applies here.

[PeteHuws]

I think he'd be fine. I left the cap off my old A4 diesel and then drove from the N Forest to London ~90miles before realising, there seemed to be no oil loss & no oil light came on; unless you're driving on an African dust road then then as Antimus says the chance of anything getting in on such a small journey would be negligible.

[Golf-Fiend]

Did the same in an old 1600 Golf. Things only went one way - OUT! And that was the oil. All over the engine bay, bonnet, exhaust. I'd say that NO dust went in and any that did would have been washed out with the oil :(

[donovan]

That's strange. My oil cap managed to come undone and didn't run properly at all. Same when removing dip stick with engine running?

[Tech1e]

They normally dont run very well as the oil system is closed and loops through the manifold so they normally cause an air leak if they are left off.

[KBPhoto]

Topped my oil up late one winter night & forgot to put cap back on! No problems until warning light came on over 100 miles later as oil level had dropped quite a bit.

Made a mess of the engine bay, but car drove fine (no loss of power or acceleration).

Has it affected the engine? Doesn't seem to have done any harm around 12,000 miles later.

Am still trying to get the oil out of the engine cover and sound deadening matting though...

[trundlenut]

I had a diesel focus hire car delivered once and they had left the oil filler cap on top of the engine, first thing I noticed was oil running down one of the headlights, when I opened the bonnet it had made rather a mess!

Didn't seem to have lost that much oil, the light didn't come on but it had only gone about 3 miles.

Seeing as the oil has decided to stay in the engine I wouldn't worry.

[Grizzle]

They normally dont run very well as the oil system is closed and loops through the manifold so they normally cause an air leak if they are left off.

Exactly what i was going to say its a sealed system surprised it ran at all.

[countryboy]

I think what Tech1e means is that the breather system for the engine that takes the gases from the top of the engine is now routed into the intake manifold and into the engine to be burned rather than vented to atmosphere to improve the emissions. There shouldn't be much problem with dust in the engine as most of the direction things would have been going in would have been out.

Ian

[Timmyboy]

your "friend"

Made me laugh

I left the cap off the first weekend I bought mine having topped up the oil - no mess or anything nasty, though it was quite obvious something was wrong as the car sounded like it was hunting and the idling was very rough.

[Luky]

Thanks for the overwhelming response , think will just top up the oil if required and leave it at that.