Oil dipstick marks

[pmansson]

Whether the stick has a hatched area or two small indents, how much oil does this represent? Less than a litre is my guess.....

[pmansson]

The reason I ask is that this amount, whatever it is, is exactly what 2 of my XKs used on a 350 mile trip on motorways on Thursday. Both left Stockholm with the oil level at the upper mark, and both had the levels down to the bottom mark, after having been left to stand for 5 mins after the 6 hr drive. Both engines/cars drive very well. No oil leaks on the garage floor, no sooty plugs or exhaust, but it seems a bit too much to me. A 3rd XK of mine used 3/4 of the amount, beteween the marks, on the identical trip a month ago.

[Heuer]

It takes 2 pints of oil to raise the level from the low to high mark so that gives you 175miles/pint which is high even for the 3.4/3.8 engines. I would expect 600 miles/pint. So if there are no leaks and you are certain of the initial and end journey levels, the dipstick is not bent and was fully inserted both times I suggest a compression test. Alternatively run the test again on one of the cars - try a 175 mile trip and the oil level should drop to halfway by your reckoning.

[pmansson]

Thanks David,
so that is 1,2 L between the marks.
About twice the amount I would expect the old XK engines to consume. One is a never opened, 3 owner, 45k mile 3,4 engine. The other is a rebuilt (in the 70s but with little mileage since) 3.8 engine.
A recent compression test showed very even readings of 7 bar on the 3.4 and fairly even readings of 9 bar on the 3,8 with triple HD8s and surely 9:1 CR.
A leak down test, perhaps....
Both engines run very well.

[PeterCrespin]

Is it the right stick? The visible parts can look similar but the internal parts Re different for different sump types/models (usually an ID stamped at the end of the stick). Plus the collar can move, or felt be omitted or too thick a piece used, both of which affect readings. Sometimes it's a bit like header tanks - if you overfill the engine can consume excess and then settle down. Older Jags have big sumps so don't be afraid to leave a litre out and see if consumption settles down or if it continues to fall.

If the 3.4 has poor/missing air filters and is/was driven in dusty environments it could be worn out at 45k. If the old rebuild/low miles 3.8 is a burner you should try using it very hard to bed it in properly. Red line it through the gear when fully hot and try to do it every trip a few times - it's important the engine is under hard load, not just revving high at steady pace in a low gear, although by this stage that's probably better than babying it. I hope it's not on synthetic or even semi-synthetic if it is very low mileage?

Pete

[Heuer]

Adding to what Pete says. May be worth draining the oil and filling it up with exactly the Jaguar recommended dose, and then checking the dip stick to see where the level comes to - you will be surprised by the variance between cars for some reason. I did it recently on my 3.8 and the correct fill of 8.5 litres came to half way up the stick hatching. On my 4.2 the same fill reaches the top of the hatching. Still does not explain why you got such a drop in a 350 mile drive though (on two cars!) unless you overfilled as Pete suggested.

[pmansson]

Interesting discussion: I have suspected the dipsticks in the past. The 3.8 is an E-type engine with a cranked dip stick, which hooks into a retainer secured on the studs for the rear exhaust collector.
The 3.8 has a straight, quite loose and fairly short stick. Nor sure if it is correct. Has no markings.
I will simply do as David suggests when I next change the oil.
I am not overly concerned as the compression test showed very good results, and they both run very well, esp the original 3.4. The triple carbs on the 3.8 need an overhaul, but still performs quite well.

[pmansson]

Today I did those same 350 miles in a 4,2 E-type with a very strong engine in good condition. It used about 20% of the hatched area, rather than the full amount as did 2 150s a fortnight ago. So with Davids 2 pints in the marked area on the stick, todays E-type consumption was very modest and fully acceptable. The car has its original 3.54 but with Uryk?s 5-speed box where I do 150km/h at 3.000, though I spent most of the time around 2.400-2.800.