God, I've never done this before and i dont think i'll do it again:(

I try and be good and decided to check the oil last friday and decided to add a bit in. Unfortuneatly i never put the oil cap back on!!! I only found out when I wondered what the steam/mist was, coming from under the bonnet this morning.

OH B*******

Thing is i must have driven a few few miles ,about 100 miles with it. Never really noticed anything. I left it till lunch to check the oil level which was about the same but i'm sure it wasnt its normal black self. I undid the coolant resevoir and had an air bubble come up the middle.

Driving back from work this afternoon though its only 10mins away the temp gauge rose a bit too quick but still didnt go above its normal level. Quick look under the bonnet and the coolant has risen slightly(expected) and has a bit of a tide( rocking back and forth) to it. When revving it the level drops.

NOw i'm going to go back with the laptop to see what VAG-COM tells me. Doesnt it give you the oil pressure, water pressure and the cylinder pressures?

Now i could imaging that as diesel is a fuel and lube of sorts that it might be alright for a brief instance, but I'm very nervous.

What should i do???

Thanks Mark

if the oil level was still ok , i.e. on the hatched area on the dipstick , i wouln't have thought that any engine damage had been done , all you've done is had another breather on the engine for 100 miles , there are no warning lamps on is there ?

don't forget the engine will warm up quicker when the weather is warmer , i saw 24 degrees C today

P.S. you should NOT really release the coolant reservoir cap if the engine is hot

P.S. you should really release the coolant reservoir cap if the engine is hot

Why should you do this?:confused: :confused:

never release the cap when the engine is hot.... i know sombody who got very badly scalded doing that...

i think that must be a typo

Why should you do this?:confused: :confused:

I'm sure he meant shouldn't!

I'm guessing ric04vrs mean't "shouldn't" release the cap - as there could be a build up of steam / scalding hot water to burn you!!!!

To the OP, I agree with ric04vrs - it probably would have risen quite quick today because it was really warm outside!!! Also, I think you'll probably be ok about leaving the oil cap off, as you said that the oil was at pretty much the same level and the car didn't overheat or sieze or anything. I reckong you'll be fine!

Presumeably you've still got the oil cap? You didn't leave it somewhere under the bonnet and now it's lost?

Edit: Damn you Tom!!! Too quick for me!! :-)

iirc the pd engine has an oil splash shield over the top of the hydraulic lifters anyway, this should stop too much oil from escaping... you're bound to have lost a bit tho, mainly just little spots all of the top of the engine

Well it seems ok, couldnt see anything wrong.

I'd left the oil cap ontop of the airbox and the bonnet lining seems to have held it in place! There seems to be oil spray everywhere, nice hole spray pattern on the lining.

No warnings came up on the dash. Would it show a low oil pressure?

I'm still not convinced, but i'll leave it a while and see how it runs.

You will only get the low oil pressure light lit if you run out of oil.

The oil splattered about the engine compartment will just offset the

corrosion in later years

unless the oil level has been topped up with coolant from a blown gasket...... but I doubt that's the case.

Why should you do this?:confused: :confused:

sorry missed a NOT out , post editted

I know from past experience with Plessey generators (where the filler cap is at the top of the sump, not on top of the cylinder head) that if you were to have lost any serious amount of oil from not fitting the filler cap, you'd have more than a few spots on the underside of your bonnet! I had said accident with a Plessey generator about 10 years ago, and around half a gallon of oil was ejected through the filler port in approximately five seconds!!!

Like TeflonTom's said, the design of the PD engine (and also the MPi engine, as it goes) allows it to be run without the filler cap on without any major oil loss. I know, because I've done so on both my vRS and my wife's MPi - not for 100 miles though, admittedly!!!

I agree with the other posts on here - I think the 'symptoms' you saw were purely down to coincidence, and I'd be very surprised if you'd done any damage at all...

to only potential problem is the ingress of dirt or moisture into the oil...

I'd be tempted to change the oil, but apart from that it sounds like all will be ok.

Nothing to worry about imho. The cap isn't a pressure seal at all really, it just stops the oil pouring out of the hole.

The movement of coolant is the water pump working harder as you rev the engine - perfectly normal.

Stop panicking!

Yeah, no worries. My parents in law drove Manchester to Cardiff without the oil cap on. Lost a bit of oil and the engine bay needed some gunk but no long term damage. As someone pointed out, there's a baffle under the filler cap which should stop some of it coming out. Any oil in there is what's left after the tappets and cam have been lubricated from there it's straight into the strainer and then filter.

If you're observant enough to notice that the temperature's risen s bit too fast, I'm sure you'd notice the temperature go through the roof as as the gasket blew and the low oil pressure light coming on too probably.

Thanks everyone, panic averted then:)

I think when somethin like that happens I tend to get very sensitive to everything that then happens, nervous for the next big bang or to try and work out whats actually wrong.

I have noticed the oil cap isnt an air seal as i see a bit of oil collect in the rubber funnel bit.

It happened to me too but oil level didnt go below minimum so i think there's no harm done. I drove it like that at least 1000 kms )