Oil levels

[malcolm]

I've always topped my engine oil up to the top of the hatch marks. I have the correct E Type dipstick, marked with an E, unbent etc etc.

I have just changed oil and filter, filling up with exactly 8.5 litres as per the handbook. Having allowed it to settle for hours, after running the engine briefly to ensure filter is filled etc, with the car dead level, the oil is about halfway (just over) up the hatch marks.

What do others find re. hatch mark levels? I assume this means I've been overfilling it previously! (unless I'm missing something!)

[Heuer]

Likely you have been overfilling. What you have done is the correct thing by filling with the correct quantity and then 'marking' where the oil level sits on the dip stick. Going forward top up to that mark. Unlikely any harm will have been done. Things go really badly wrong if you over fill to the point the crank is under the oil as it acts like a whisk and aerates the oil which will then not go past the pump.

[malcolm]

Thanks David. I'll do that. But why would the correct quantity read down the hatches with the correct (straight) dipstick? I would be interested to hear what other peoples sticks say.

[mgcjag]

Hi Malcom....if you look at the service manual it just says to check oil stand car on level ground and if oil level is in the knurled area hot or cold then no need to add oil...........it isnt marked as a high or low level......mine is kept around the 1/2 way......Steve

[chrisfell]

Malcolm, Others will disagree with this, try and tell me I’m trashing my engine and forecast all kinds of damage that may be caused as a result, but...... this is my experience with my car’s engine for all of the last 16 years and over 60,000 miles.

I always overfill the sump. Top of the hash mark and then a bit extra. This means my engine usually has around 9 litres of oil in it when freshly changed. During the next 3,000 miles another 1 litre is poured in to maintain the oil level at top of the hash mark. At 3,000 miles I change the oil again, another two cans, 10 litres each change. I probably loose 2 litres to the floor in that time, most of it from the cam feed pipe, some from the timing chain chest, and a little gets blown through the valve guides. None of these losses is due to oil levels, (although they would be cured if the amount of oil in the engine was reduced to nothing).

Oil at this level does not cause my engine any ill effects at all. It starts runs and stops just like any other engine. It doesn’t froth the oil, nor drag the crank, nor any of the other many problems others claim it will. The benefit of keeping it topped up like this is (a) I can do a very long journey and not have to worry about the oil level falling off the bottom of the dip stick; and (b) I don’t have to carry a litre can of oil everywhere I go.

Of course YMMV.

[christopher storey]

Chris : this is an observation rather than a criticism , but , if you are putting 10 litres in at a refill then you are , quite definitely, overfilling the engine by some 15% . Although you lose some of this over the next few thousand miles, part of the loss may indeed be the result of the overfilling . With all due respect, what is the point of it ? The correct refill amount is 8.5 litres, and more than this will not lubricate your engine any better , and may indeed as others have pointed out lead to frothing and /or cavitation at the oil pump, which are not trivial matters and one day may cause harm. The XK engine otherwise is virtually bomb proof however tired and old it may get, and to do anything which may compromise this in some circumstances, seems to me to be a retrograde step

[chrisfell]

Maybe my explanation was confusing, I fill with 9 rather than 10 litres, adding the next 1 litre over 3,000 miles as oil is burned or drops onto tarmac, making a total of 10 litres per oil change.

I stand by my experience, that my more marginal overfilling hasn’t damaged my engine yet, and as already stated, the car is used a lot.

[christopher storey]

Chris : ah, I see - that is a trivial overfill of about 0.5 litre and I can't see that it would cause Harm

[Heuer]

A member here had his engine ruined by filling with excess oil (quite a lot of it though). Once the level in the sump rises to be in contact with the crank the afore mentioned frothing occurs and the oil pump can't deal with it.

[Mark Gordon]

Another issue with filling to the top of the hash marks, anectdotally reported I admit, is that that can lead to an increase in oil leakage from the rear main seal. I see no reason to fill beyond halfway on the hash marks.