Morning,


Last year I replaced the timing tensioners and chains on my 2002 XJR.

A few weeks afterwards I noticed an oil leak coming from the front timing cover. Initially I thought I'd snagged, or just ill-fitted the seals. I left it leak for a good while as I knew the fix was doing the whole job again, in terms of disassembly, to replace the seals again.

I was loosing about 1l every ~500 miles. Upon start up I could see it seeping from the timing cover.

Recently I had a CEL with restricted performance. OBD pointed to the TPS. I started the strip down to check the connectors and found all clean, apart from the air filter and induction piping. They were both rather oily.

My assumptions was oil spuing out of the full load breather on the RHS (driver's side), coating the filter and confusing the TPS. I performed a hard reset and this got me home where the car's been sitting since.

After searching, I was looking at cures for high crankcase pressure, something that would explain both oily filter and front end leak. I went to clean the part load breather with the suggested methods, but it was already sparkly clean and drill bits and pipe cleaners were just coming out with fresh oil, no crud.


Apart from that, I've just performed a compression test cold.


My results, in psi, were:

1: 132
2: 138
3: 135
4: 132

5: 125
6: 130
7: 138
8: 135


The engine has just rolled over 200k km. Could someone please advise me on these results? Are there any other suggestions?




Cheers,
- Richard

 

If you are sure that the part load breather on the LHS valve/cam cover is clean, then theres only one other thing I can think of. That plastic corigated hose from the part load breather going to the throttle body elbow might be melted or collapsed under the intake manifold. I would also say that the same hose has a crack in it but then the car would be running rough even though you mentioned a RP light but was a TPS code. Even though it's not an easy job, I would recommend replacing that corigated hose first.

 

Dickie, I'm rather confused at your first sentence, replacing the timing chains and tensioners on the 100? Did it have plastic tensioners fitted? If so it's not a 100 spec' engine and likely a replacement? All 100's are fitted with the last of the AJ 4.0L AJ27S units and they share the later 4.2 AJ33 timing chains/tensioners so do not require upgrade parts...

Loosing oil from these engines isn't good, just suck it up and get the work done to replace that leaking seal.

 

A plugged or partially plugged Part Breather hose will cause the Full Load Breather to suck oil into the air cleaner and air intake tube. It is also possible that the plugged hose may contribute to the seal leak. I would look at clearing the hose before tearing into the seal.

 

Just start the engine with the part load breather disconnected and see how much air it pulls. If it is collapsed or plugged the engine should keep running smoothly. Also see if air is being pumped out of the cam cover opening.

 

That's a whole other story. Yes, I was getting paranoid about the tensioner issues that have all forums lit up.

I ordered the complete kit, tensioner, guides, seals. Ordered a pulley. Bought the timing tools and had it all shipped to Switzerland. I had a couple of friends over to help and during the strip down saw that of course I had the later tensioners anyway.

At that point the bonnet was off, engine was being stripped and I had help. I had the parts and tools in hand, so I decided to go ahead with the replacement. I felt that the plastic slippers must have worn since 2002.


In hindsight I would have just left everything as I had issues along the way and now a leaking engine. How it goes sometimes...




I will fire the engine up and check the lines as suggested. I assume I'm checking for a negative pressure on the breather tube going to the TB, and a positive pressure coming from the cam cover nipple?

What magnitude of pressure am I looking for? Enough to whistle on the cam cover?



Cheers,
- Richard

 

Ok, this might explain the cover leakage.
There are several threads on the UK and Dutch forum on this matter (but I am not sure if also here on the Jaguarforums).

There are replacement seals which are thinner than the original OEM, while other replacement seals are of the same thickness as the OEM.
Very confusing, and it seems to depend on the manufacturer of the seals.

People using the thinner seals seem to get leakage after several hundred miles.
The seal cover bolts have studs, preventing them from tightening them closer, thus leaving the everything to the seal.
Obvious the thicker, correct seal does the job, the thinner one not.

I will have to dig up an old Dutch thread if there is no other member having more info on this, but I remember the thinner ones were all one color, where the correct ones are black and red (one color left, other color right side).

 

Thanks for the info. Are you talking about the cam covers or the front timing cover?

I seem to remember my cam covers were different colours, but the front timing cover seal was two open-end seals, upper and lower.


- Richard

 

Richard, sorry, I read to fast, and presumed it was the cam cover, sorry.

 

The AJ26 cam gaskets are thicker and one side is gray, the other red. But the 2002 is a AJ27 and the gaskets are thinner.

 

Have you checked the metal mesh between oil sump and pump? Mine was 80-90% clogged and this caused very high crankcase pressure. Cleaning the mesh resolved the oil leaking problems. Maybe not your issue but one thing to check.

Your compression test results are in line with healty engine at those Kms.

 

-UPDATE-


The car's been sat for a good (not good) while now. Today I took out the fuel relays to get some oil circulating and then fired her up to check the part load breather (which I had disconnected).

The whistle was loud, and the negative pressure from the breather line was quite impressive actually. I couldn't feel any positive pressure from the nipple on the cam cover though. Should I?


Any further advice welcome. I'd just really love a non-leaking Jaguar one of these days.



- Richard

 

UPDATE II


I put in a fresh air filter and went for a drive last night. When the car had just fired up, I removed the oil filler cap and couldn't feel any puffing.

When I returned home I removed the cap again, still not feeling and pulses or seeing any smoke.


Today I checked the air filter and could see two small oil drops. Either these are legacy drops, or I'm going to have a soaked air filter again soon.


Apart from that she drove fine and I kept an eye on all (that I could) temps/pressures with an OBD reader.


Advice welcome.

- Richard

 

So you have a whistle from the bank 2 part load breather... That's good. The part load breather tube (black accordion tube) that runs under the S/C I have seen completely collapsed, broken in multiple pieces and finally clogged. You need to find out if yours is anything like I mentioned. I've never seen it but I bet it's possible that the aspirator (?) valve on the firewall can be non functional... Just a thought. If that whole system doesn't work, it can cause oil leaks as well. A leaking timing cover gasket is also entirely possible because of it's age/mileage.

 

Thanks.


Would it be pulling that strong of a vacuum if it was collapsed/clogged?


I can see the leak is from the front timing cover which I replaced under 500 miles ago with the timing chains/tensioners. I can see the oil on my air filter coming from the full load breather.

I willing to accept I might have just put the seal in badly, but this doesn't explain the oily air filter to me.


How does one check this aspirator?



I took a drive to work this morning and ending up going into failsafe mode. Code was P1121 - TPS out of range. I did a hard reset at the side of the road and got home to swap cars.

I might start a new thread on this. I'm wondering if that's related to oil coating the TB/Intake tubing and playing with the TPS. Everyone seems to say it's not serviceable and you have to spend thousands on a new TB, but I'd like to remove the TPS potentiometer and clear it out/check the tracks for cracks. All connectors are clean. Thoughts?



- Richard

 

I suppose it's possible, but not very likely that the oil is causing the throttle body code. That might need a separate thread started. There's actually tons of threads about this so just use the search function.

What I would do to check the part load breather is disconnect the hose from the left side of the throttle body elbow and the left side valve cover (or cam cover) and using light compressed air blow thru the tube. I'm afraid that I don't know the check on the aspirator valve. I don't even know if that's the correct name of that component on the firewall either. That's why I had the "(?)" on there. If you can just verify that your PL breather tube is in good shape, not collapsed and not clogged, then that's the next step.

 

Thanks.

So, I managed to get the PL breather tube of the firewall/'aspirator' nipple and blew through. There was no resistance and it inflated the glove I had on the TB:



I did the same from the cam cover end and it also inflated the glove with no resistance.
I felt like I was playing bagpipes with the engine, but to me I am sure the PL breather is clear.


As for the TB issue, I had a feel of the PPS drum and noted that if I very gently released the drum, it didn't click shut, maybe 0.5mm from closed. I backed off the bracket 1/4 turn and now when I gently release the drum I can hear it click home. Would the PPS be this sensitive that it would throw a code/restricted performance?



- Richard

 

Yes, the throttle body's are very sensitive. If you found that, then great! Go with that fix for now and continue driving.

Hmmm.... If the corregated PL breather hose is free of any defects, obstructions, no vacuum leaks and you're sure that you inserted the proper drill bit into the PL breather in the cam cover far enough, then you should have a fully functioning PCV system. How is the power output from this engine? How is the engine idle quality after it has reached operating temperature? You need to get ahold of a good quality vacuum gauge and see what kind of readings you get at idle. If I get a chance, I will try to do some research today while I'm at work. My only other thought is on that timing cover. If oil leaks out then air can get in. In theory you can have a vacuum leak rendering the PCV system useless or nearly anyways. When you redo your timing cover gasket, you really need to use silicone sealer on the entire parimeter on top of new seals. It's so time consuming to do that and only have it leak within a year is not feasible. Even with new seals on an engine, I still use sealer. These engines are a little bit of a pain to keep oil leak free.

 

Thanks again.


The cam cover nipple for the PL breather is clean. I used a 2.5mm twist drill to check and I only get the smallest microns of carbon on the flutes. They also got cleaned fully when the covers were off for teh timing chain job.

Engine performance is strong, and hot/cold idle is rock solid and smooth.

I don't have a vac tester, but I could go around the lines with some carb cleaner and check for a increase in idle, the old school way?



When you recommend Silicon sealer, are you talking about the nasty black generic RTV sealer? Or would it be better to use non-setting a Hylomar Blue?



- Richard

 

You can check it the old school way but, you might not have any vacuum leaks since you said it runs/idles smooth. Besides, it would have a check engine light with lean codes if there was a vacuum leak. It wouldn't hurt to check it over anyways.

As far as the RTV silicone sealer, I would use the ultra copper orange. Make sure the sealing surfaces are very clean and dry first. It's still pliable after it dries and conformes to the components while expanding and contracting during hot and cold cycles. The blue stuff you speak of is more like a paste to me. It's too soft and doesn't seem to cure to my liking.