Hello from Bulgaria.
I apologize if you already have written on this topic
I have x-type 3.0l V6, use full synthetic engine oil (5w40) and noticed that about 10,000 km, the engine is burning about 2 liters.
I looked the car everywhere, no leaks, no blue smoke.
Do you think is normal to have so much oil consumption? Or I have a problem?
Should I try 10w40 next time?

 

vassilev, first off, a true full synthetic oil is a much thinner oil than the oil rating is (the rating is based on the effective characteristics of a dino oil, not on the actual characteristics of the full synthetic oil). So, a synthetic oil has a much smaller oil particle, and therefore can get into more crevices to leak out of. In your case, you are more than likely getting oil by the rings or by the valve seals. The easiest check is to put a cylinder at TDC (this will have all valves shut for that cylinder). THen using an adapter, you remove the spark plug and connect an airline in where the plug was. Pressurize the cylinder to around 90 psi. Now you can listen to the exhaust and intake for any signs of air leakage. You can remove the oil fill cap and see if you can hear any air there. Where you hear air leaking out at is where the oil most likely is leaking out at.

A little bit of oil leaking past the valve seals can result in no blue smoke. I have seen Ford documents saying that oil consumption of up to 1 quart/liter per 1000 miles/1500 km is deemed "acceptable" by Ford.

Just to get clarification on the subject, have you recently switched over to full synthetic oil or have you been running it for some time? Also, did this amount of oil consumption just recently start? You may want to also check the PCV valve as if this sticks open, it can suck in a small amount of oil only during normal operation and result in no blue smoke.

 

Thanks a lot, but I cannot believe that 1 liter per 1500 km is acceptable?!!
Recently changed PCV valve.
And should I remove the cilinder head to change the valve rubbers?
What oil would you recommend in this case?

 

I believe the conventional oil recommended is Castrol 10-40. 1 liter per 1500km would excessive in my opinion, 1 liter every 10000km is excessive too.

I go about 15000 between oil changes, sometimes 20K. I use full synthetic and have yet to have to add even 1/2 a liter between changes.

I have an X5 with a 3.0 in it, and find that I have to add a liter every 10000 or so. BMW admits that the 3.0 is an oil guzzler. I've driven behind it and the only time you see anything from the pipes are when you hammer it from a standing start and it's just a single small puff of smoke.

 

vassilev, I didn't say that I agreed with, just giving a verifiable source for reference. LIke you, that to me is excessive.

As for oil, I run conventional 5W-30 oil in my car. If you are in an extremely cold climate or have an 05 or newer car, then run 5W-20 oil. But then, I change my oil every 6000KM (4000 miles). Call me **** about changing the oil, but I consider it cheap insurance for the motor.

 

To further elaborate on this, "full synthetic" has a different meaning in the US and EU due to regulatory constraints.

In the US, hydro-cracked base stock can be called full synthetic. In the EU, it cannot be called full synthetic due to consumer protection regulations.

That is why some international oil brands with "full synthetic" on the front label also carry on the back label the words "NOT FOR SALE OUTSIDE OF USA/CANADA". It has the same product name in Europe, but the formulation is different in the two markets.

 

You may be chasing a non-existent problem.

1 liter in 5000km is not very much if you frequently drive fast. The 5W-40 is quite thin. You could try 10W-40 and see how it goes. Certainly it is worth trying a different oil before doing anything else.

Some perfectly healthy motors will consume as much as 1 liter in 1000km. And that is running 20W50.

 

Thank you guys, the truth is that I love my car, I feel a real pleasure to drive. Another thing is that I drive pretty fast sometimes, because this engine does not like to move slowly.
Now here is summer and is very hot, the car heats up quickly, behaves perfectly on the road.
I take care of everything for the car. Therefore worried that the oil disappears without reason. So the thin oil, combined with faster driving is the cause.

p.s. the car is 2002 model,about 150,000 km

 

uhm it really depends on what is the issue. Using a thicker oil than the base jaguar recommendation (5-30w) can result in poor oil control by the oil rings based on temperature and useage. The use of thinner lower tension rings for better mpg and hp is widely used now. The new 5.0 uses 5-20w. Porsche 0-20w. A thicker oil is harder to control and results in more consumption. Now on the other hand if you have scratches cylinder walls, differant climate temps, driving style, etc.. you may need a thicker oil. I dont know what the climate is in bulgaria. But i would go to a 5-30w and maybe conventional and see what change if any you get on the consumption issue. Then try the other way on viscosity depending on useage results. I also recommend trying engine restore dont know if avail in auto parts stores in your country or not, but its a very good additive for issues like this. I dont have to add any oil on my jaguar between 5k oil changes at 140k
but my nissan truck 2qts. with 60k. But then its highly modifyed, supercharged and driven to 7k shift points regularly and does have a little blowby.

 

Ya, 1.7 quarts in 5000 mi (yea English units... ;-) is going to be hard to track down. Just checking the oil level 8 fill ups, or so, and topping up when necessary would be much cheaper than considering valve or ring replacement.

Look for any changes over time but if the consumption holds steady than just live with it.

If the engine starts increasing the consumption of oil then other things might be in order.

The olde hotrod trick for locating oil use (assuming no leaks are found) was to take compression checks. Use a pressure gauge to measure the compression in a cylinder. Then squirt a small amount of motor oil into the spark plug hole and recheck the compression. If there is a marked increase in compression the oil rings are leaking. If there isn't then the suspect is the valve guides. This is because the small amount of oil introduced will momentarily seal the oil rings but will have no effect on the valve guides.

Unfortunately for our cars it appears to be a real bitch to get at the rear spark plugs so this test is probably pretty hard (i.e., impossible) to accomplish.

So, just check the oil and enjoy the ride...
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Jaguar: Grace, Pace, and Space - Sir William Lyons