Too much oil?

K

ksimpson

Member
Hi,

I did a service on my wife's 1.6 FSI Sport yesterday. I added 3.4 litres of oil and dipped it - nothing showing on the dipstick. Ran the engine for 5 mins, let it settle, still nothing there. Added .25 litre, ran the engine and checked - still nothing on the dipstick. Added another .25 litre, same thing.

I then added a further .25 and the oil showed in the middle of the two markers. I took the car out and got it up to full temperature and the oil showed the same which I was happy with.

Just to be sure, I took the car out for a drive this evening getting up to normal temperature and let it sit for 5 mins. I checked the oil and it's now showing above the maximum.:mad:

The dipstick is a nightmare. How are we supposed to know how much oil is in our cars!!

What should I do, drain some or leave it and let it burn off?
 
Last edited:
Hi Ken
I have a diesel and the oil level seem much easier to check accurately than on the petrol cars.
If it was my car, I would let it stand overnight then check the level again. If its no more than 5mm above the high mark then leave it. If its approaching 10mm over then drain some off. The main risk is that if the crankshaft is continually dipping into the oil, it froths and aerates the oil, resulting in low oil pressure.

Cheers Spike
 
Thanks Spike, I'll leave it. I reckon it's just above the max. I'll keep an eye on it over the next few days.

I'll order one of the later dipsticks that has the orange tip. That should be a lot easier to read. I'd love to meet the genius that decided on the black plastic tip.
 
ha i have the same problem i can never tell how much oil ther is the dip stick is useless
 
I'd remove some oil as it can, when over full get into your catalytic convertor and kill it sufficiently to fail the emmissions test at MOT time, don't ask me how it does but it's well know to happen.
cheers mike
 
tdiman said:
don't ask me how it does but it's well know to happen.
cheers mike
Click to expand...

The oil collects on the front face of the catalyst and then oxidises (burns!) over the catalyst when the engine warms up. This is 100-1000 times more oxidation than it is designed for (designed to oxidise unburnt fuel to CO2 and water) and so it gets a bit warm!!! The ceramic brick (onto which the catalyst is coated) will melt at 1500oC, which is a real possibility if enough oil is deposited.
Interestingly this "exotherm" problem can be caused by engine misfiring, and push starting the car. As in both circumstances unburnt fuel can be transferred into the exhaust system.
I have seen this on test cars and it isn't pretty!! It is the equivalent of the comedy banana in the exhaust, as the brick melts and blocks the gas from exiting.
Long term burning of small amounts of oil (like in a diesel or rotary engine) is fine as the catalyst is designed for this, though the additives in the oil (zinc, phosphorus etc) do slowing kill the performance over a period of 5-10 years, hence the life time often quoted.

Hope that explains that one, car catalyst design and manufacture was my job for 5 years!

David
 
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