My 2000 XJR with 110,000 miles on it started running rough today on a 10 mile trip. On the way home, it started losing power, and then the "Low Oil Pressure" light and warning came on. No previous warning light, and it ran fine yesterday.

Oil level is fine.

I immediately pulled over and parked the car.

What's up?

 

perhaps oil pump failure or timing chain tensioner failure.

I recently had an oil pump fail on a 1997 xk8, which is strange to me but it does in fact happen.
What happened was the oil pressure plummeted and caused a camshaft to seize and various other atrocities down below.

Have you taken the valve covers off?

 

Is the oil pump somehow connected to the timing chain?

 

If the secondary timing chain tensioner on either bank fails then you have a MASSIVE oil leak inside the engine.

The tensioner uses oil pressure to keep tension on the timing chain between the intake and exhaust cams.

The originals are plastic bodied and when they fail, they can lead to a broken chain (rough running) and then let the oil flow freely, causing a drop in oil pressure.

This just a guess from your description of events.

bob gauff

 

I wouldn't panic yet. Find a good jaguar mechanic and take it to him. It could be something simple like a bad connection or bad fuel. I suspect the low oil pressure light came on because the engine stalled.

 

Motorcarman - that is interesting.

Have you ever come across the actual cut off dates for the various tensioners? We have a local Jag mechanic and he is saying with the 02 and later -- don't worry about them until higher miles ... and my trusted parts guy at the dealer said Jag never installed the 3rd version in any x308. I know it has been posted on this forum that these cut offs exist ... but have never been able to prove.

 

Any 4.0 engine that uses the newer style oil pump (C2A1409) has the metal body primary and secondary chain tensioners. This includes the silent running chain as part of the engine enhanements.

There was a TSB (100-21) that listed several 2002 MY X308 cars that might have had oil pump issues. The TSB lists the problem vehicles from VIN F44114-F55936 so I know that the newer parts are fitted from 'at least' F44114 onward.

All 4.0 engines from #0108130000> have the upgraded components.

Your 'trusted-parts-guy' needs an 'edumacation' on superseded jaguar parts and the progression of updates. It's all in JEPC if you take the time to do some research.

bob gauff

 

So Jaguar upgraded the oil pump / tensioner and chain -- and had a problem with the new pump! That TSP should in with the others -- great information.

Very interesting: Mine is an August 2001 build. Model year 2002 F45829 so what you are saying is that mine has the potential problem pump -- But - I have the metal tensioners and upgraded chain. Thought I had the engine number for this one -- now can't find it.

What was the chain difference?

Changing the pump is a big job! -- I also don't see new tensioners being specified in the parts -- I guess because they are the newest style. Looks like Jaguar built over 11k before this was noticed.

For the OP -- I Guess we can hope if this is the problem -- it was only one tooth.

 

all that to replace an oil pump?

at least the TSB can double as a primary tensioner replacement guide

and all in 6.8 hours too!

 

Thanks for everyone that stayed on topic, especially Motorcarman who PM'd me.

Got the word back from the dealer; the primary chain failed (left bank), taking out a tooth on the sprocket sending metal parts into the sump. It's therefore apparent that the left bank valves are bent (the low power thing). The dealer thinks the engine is junk.

My options seem to be:
1: get a (rebuilt) engine and put it in (I could do this myself)
2: Scrap the car

Thoughts?

 

I have not seen a PRIMARY chain break but I don't doubt that it can happen.
Are you SURE that it was a PRIMARY???????

Secondary chains break and the result is NOT always bent valves. I bought a 1999 XJ8L with a broken chain and simply replaced the chain, guides, tensioners and gaskets and I still drive it YEARS later. (the other 3 chains are FINE)

Plastic and metal parts falling into the pan means NOTHING. They can be retrieved and the pan reinstalled.

Having worked at Dealers I can say that taking an older car in for repair might NOT be a good idea. Some will NOT repair major components like engines and gearboxes due to future liability issues. Some mechanics at repair shops (dealer OR independent) are TOTAL INCOMPETENTS!!!!!!!! and may have never attempted an engine repair so they just feel comfortable replacing it.
Some service managers don't let the service dept install good-used engines or heads etc. (only NEW)

Opening up the engine and then just throw up your hands and say "It's destroyed and you need a new one" might be an incorrect diagnosis.

Just my opinion but then again I try to have an optimistic view about mechanical things. I seem to find ways to fix things that people think are junk and throw away.
When I was a kid I used to bring home lawn mowers on my way home from school that were sitting in the trash pile in front of a house. A few days later the engine was powering my go-kart!!!!! Just needed the carb rebuilt.

bob gauff