Checking the oil level - engine hot or cold? (VW TDI)

[ricotansky]

I've got a VW Scirocco 2.0 TDI 140 and have been given conflicting advice by different VW dealers with regards to checking the oil level. One says to check it when the engine is hot (a few minutes after switching the engine off so the oil can drain back into the sump). Another said to check it when the engine is cold.

My dilemma is, that the level is low when cold and looks ok when hot. So who is right? Do I top it up because it is low when cold, or leave it because it is fine when hot?

Also, does anyone know if the same rules apply to the VW T5 van with the 140 TDI engine too (I have one of these as well).

Thanks in advance

Rico

[JuniorD]

I don't think 'hot' or 'cold' will make a huge difference, but surely the convention is to do it before start up or at least 10 or 15 mins after the engine has been shut down and the oil level has settled.

[Blaster72]

There's normally approx 1 ltr difference between max and min on a dipstick ( not in all cases though )

I'd say if its low when cold and not max when warm then stick a bit more in - ie don't let it go below min when cold or above max when warm,

I've always checked the oil with a warm engine and never had any problems so far.

VW's own idiots guide doesn't specify hot or cold

http://www.volkswagen.co.uk/owners/how-to-guides/h...

[ricotansky]

Hmm thanks, I've topped it up a bit. I guess I'll just make sure to keep an eye on it and keep it between the lines!

Cheers

[Sheepshanks]

Oil level is generally done with warm engine these days. And on many cars by dash readout, not dipstick!

The theory is you fill up with fuel, then check the oil level. Overfilling a turbo engine can be really bad!

[SuperchargedVR6]

Only if you put so much in, the crank is sloshing around in it and aerating it.

[Adrian E]

Audi advice for checking it via electronic display is to check it warm - park on level ground and shut off the engine, turn ignition on and wait 2 minutes for oil to return to the sump, then check the display.

I don't trust the MMI so have spent less than a tenner on a good old fashioned dipstick to go in the blank they use to suck oil out of the engine at services (aka the dipstick tube!)

Shouldn't be much difference hot or cold, but it's obviously runnier when warm so more likely to be accurate and less weather dependent.

[Sheepshanks]

SuperchargedVR6 said:

Only if you put so much in, the crank is sloshing around in it and aerating it.

I forget the numbers now and don't want to make them up, but a surprisingly small amount is circulating around the engine at any given time, and oil expands quite a lot in volume when hot. So fill to the top mark when cold and it can be considerably over-filled.

It's a known issue on Merc's, for example - if filled up when cold they'll put the high oil level warning on when the engine hot.

[SuperchargedVR6]

Sheepshanks said:

SuperchargedVR6 said:

Only if you put so much in, the crank is sloshing around in it and aerating it.

I forget the numbers now and don't want to make them up, but a surprisingly small amount is circulating around the engine at any given time, and oil expands quite a lot in volume when hot. So fill to the top mark when cold and it can be considerably over-filled.

It's a known issue on Merc's, for example - if filled up when cold they'll put the high oil level warning on when the engine hot.

Not disagreeing with you, but as much as a litre flows around an R32 engine whilst the engine is running, which is why it has a 6 litre sump. I've also drained an R32 and only 4.5 litres came out. 1.5 was held in the filter and engine. That is what can lead to over-filling.

I've never had any problems over-filling the oil in any of my VWs, past and present. Obviously it's not something I've done deliberately, but for the reason mentioned.

The main reason for not overfilling the oil is because of emissions. PCV valves can suck excessive oil into the intake and chuck it through the cats, destroying them.