Hi. Sorry for the short post, but I'm writing from a smartphone on the beach at midnight.

The short story - two days ago we decided to spend some time in Greece and we came here with my XJ. Everything was ok, but the last 100km. was a mountain road with a lot of curves. Then I noticed that each time I enter a curve, I get an alert on the dashboard for a second saying "Low oil pressure". There was no place to stop the car so I checked the oil when we arrived at the hotel in Corfu ( island near Greece). I took the oil deepstick an there was no oil at all... Today we finally managed to find where to buy engine oil. The strangest thing is that it took 3 litres until the deepstick was on tha max level.

My questions are:
1. What could I possibly have damaged with driving the jag with such a low oil level?
2. What could be the reason for losing so much oil in just a day driving ( about 1200km)? I checked everywhere - there is no leaks at all, my head gaskets are new, no oil in the cooling system neither water or antifreeze in the engine oil... No strange smokes from the exhaust, no strange noises from the engine... The idle is stable, the acceleration was normal and no faults at all, except on the curves.

Please, tell me something cause I'm in shock insteed of enjoying the holidays at the sea.

 

No real idea, other than fast driving.

But, you should stock up on oil before leaving, and check the oil at every fuel stop on the return trip.

You can run the oil at 1 litre above the max mark without danger. There were certain models with that fill specification to ensure cornering did not starve the engine of oil. Search on "silverstone" to find that discussion.

 

The GOOD news is your takes 7-8 quarts with the filter, so you were not "out" of oil, just low.

How many miles did you drive? You can burn through a quart in 1000Km I suppose, AND if it was in the middle it may have seemed ok when it was actually a bit low.

Did you check it at different temps? (cold one time hot the other) that would give you results that would *seem* far off, but if checked cold/cold or warm/warm would give you apples to apples comparisons. For the record, the correct temp is fully warmed up- turn off car, wait two minutes then check level after wiping dipstick and rechecking.

Check your level at every stop for petrol and monitor the change- but for heaven's sake don't waste a good holiday at the sea worrying.

Please report back your findings!

 

Thank you for your support in time of crisis
Plums, I know about the max level of the dipstick but I preferred to have one litre oil as precautions in the trunk and run the car on the dipstick actual max.

I'm already in Bulgaria, half way to home and up to here the oil level is still ok, but it's certain that the car is "eating" oil - for 600km. I've lost about litre of oil ( after filling it was on the maximum, right now is at half between max and min...

Still - no visible signs of leaks, neither smell or color smoke from exhaust.

I'm checking always at equal conditions - cold/cold or warm/warm... I was checking the oil level on each stop and it was going slowly down each time.

I'm not driving fast at all - never over 3000 RPM (130km/h on highways and around 100 on other roads), except when overdriving... I even didn't want to step on acceleration when climbing hills.

The engine is working so fine... I even did a diagnostic with my laptop through OBD and there is no errors. It still mistery for me... It's good to be home with a running car but it's obvious that I'll have to fix something.

I'll keep you in touch guys, but I still need your advices and ideas on this case.

 

Only a couple ways for oil to exit-

Breather (will show up in air intake)
Seals (will show up on the ground or on the chassis)
Combustion chamber (will show up as blue smoke or black spark plugs)

My bet is combustion (maybe worn valve seals or blow by from worn rings)

A quart per 800KM is not fun, but you may be able to keep driving it until you are able to spend the time/money to resolve the issue.

 

My bet is the same... Because the part load breather is with normal whole and there is no oil leaks on the air filter... neither I was able to find any leaks (the engine body is absolutely clean and there was no oil drops on the ground under the cat).

Having in mind the quantity of oil that disappeared I suppose that the problem is with the combustion chamber (strange - there is no visible smoke at all even at high RPM). Today I'll visit my garage and I'll check the spark plugs. I believe I have worn piston rings (I'm not sure if this is the right word for this - in bulgarian it's "segmets"). Is this the "valve seals" and shall I check the head gasket as well?

Can you tell me the part number of those parts?

 

If you have worn piston rings (segmets) you will burn oil.
How do you know they're worn?

 

I don't know for sure... but this is the only logical explanation to "where is the oil" case I'm trying to solve in the last few days If there is no leaks, the oil is burned out... isn't it?

Actually a few hours ago I checked again the exhaust... I tried to wipe a little bit from the pipes and I noticed that the black residues are a little bit oily... or at least it's very difficult to clean my hands after touching the exhaust while touching the pipes of other cars is much easier to be cleaned. (what a technical explanation )

So I'm stick with 3 ideas what could be the reason for this:
1. Piston rings - Part number: JLM20147 (my VIN is 8367**);
2. Valve seals - still looking for the part number
3. My engine oil is too "thin"...?! New idea that came from one of my colleagues... But I'm running the car on MOTUL 8100 X-cess 5W-40... Maybe a 10W40 would be better?

 

Ok, I have some update over this case. I'm now sure 100% that the engine is burning the oil. I noticed blue smoke - the only problem is that it appears only slightly on high revs - when reaching 4500 and more. The only question left is: where exactly is the problem? Is it valve seals or piston rings?

Unfortunately there is no easy way to find out... both parts need work over the engine. Nevertheless I had an idea about how to check, so here is what we did in last few hours:

As much as I know, if the problem is related to the segments (piston rings) then the engine would have low compression. The bad news is that right now I don't have access to a manometer to check the compression in each cylinder, so we did few simple tests:
1. Cold start of the engine - when the compression is low, the engine should be difficult to start and should take longer than normal. My car is starting almost immediately.
2. Worn segments would produce excess of pressure from the dipstick whole - mine doesn't.
3. Low compression would affect the engine power for sure... The easiest way to check the engine power is to try the max speed of the car and the time for acceleration. Both seemed to be fine (max speed 225km/h at 5700 RPM).

So based on this "home made" tests my bet is on valve seals.

Any comments? Can someone please tell my part number for valve seals?

 

1. How many miles on the engine?
2. When was your last oil and filter swap?
3. How often have you "normally' had to add a quart?

 

1. The car is at 160'000 miles (250'000km);
2. Last change of oil was 6 months ago and I had 7000 miles (11'000km) on it;
3. I bought the car 8 months ago I have done only one oil change until now. For all this time I had to add engine oil only after changing the cam cover gaskets and then I had to add about a liter. Except for the last trip to Greece I have never seen the oil level to change even with a little bit...

 

That helps-

I am guessing you mean you put 7000 miles on the car.... with that high mileage (160,000 miles) I wouldn't be shocked at losing a quart every 800-1000 miles... An oil change may help with additives [insert flame war here] it may burn less.

Does it smoke blue noticeably when you accelerate or decelerate? Either way, you have some work to do- although rebuilt heads will cost much less than a rebuild...

You aren't at an emergency point though, as long as you watch the oil level every time you fill up petrol.

 

Over the years I have worked on several cars with worn valve guides and/or bad seals. They typically blow smoke on startup after sitting overnight but not that much on acceleration. You may not see much smoke when accelerating if the cats are hot, assuming you have cats, so even worn rings may not be obvious. A ring problem should produce more smoke if you use the engine to decelerate in a lower gear, then hit the power again.
RJ_____________
97 XK8 86K mi

 

Yes - it does exactly as you describe it... And I have a white smoke PUFF some times in the morning after a long stay, but I was assuming that it's because of the LPG installation that produces water vapors in the exhaust

As much as I can count I should have 32 valve seals...? Can you tell a online shop in UK with reasonable prices for jag parts where I can find such seals?

And another question - as I changed cam cover gaskets just a month ago... should I buy new ones?

 

One strategy for oil consumption that is not causing any other difficulties is to just keep on topping up the oil. It's a lot cheaper than replacing parts, even over an extended period of time. You might burn 24 extra liters of oil in a year. That's not a lot of money compared to replacing valve seals.

You can also consider a thicker grade of oil that is less subsceptible to burning. Perhaps 10W40, or 15W40. Castrol and Shell both have good conventional oils in those grades.

 

If you do decide to take the covers off, which is very dependent on how many km you drive per year, the gaskets will probably be good, as they are really flexible seals, not gaskets. But if you decide to replace the valve stem seals, the cost of new valve cover gaskets would seem to be a minor detail.
I am still of the opinion that if that amount of oil is getting past the valve stems the guides must be worn badly, in which case replacing the seals will not be a long term fix.

 

A question to the forum: does this engine have nikasil liners?
RJ________________
97 XK8 86K mi

 

It's listed as a 1998, so the original engine should be nikasil. Estilian is also powered by a LPG conversion he described some months ago.

 

Plums, typing faster than thinking, and I am a two fingerer. Would the cats survive that much oil, or does he not have cats?
RJ

 

No idea on the cats. Especially on a LPG conversion. But lots of cars can burn at that rate and pass emissions to boot so their cats must be ok.