04 XJR with 114000 kilometers. Runs fine at low revs, but as revs climb to about 4000, the engine loses power and knocks (rattling noise.) Restricted engine power light came on a couple of times before changing spark plugs (NGK Iridium.) Drivability improved with new plugs, but high rev knock still there. Any suggestions?

 

Uhhh, can you say catastrophic failure? Sounds like rod or main bearings to me.... That is a guess without listening to it. But I've seen it before. Only at 4k, huh? Are you sure? No noise at idle or through the RPM range? Could also be valve train, chain tensioners, chains, etc, etc, etc. But on an 04, chain tensioners, and chains rarely scream out for mercy. Valve/cam issues are even more rare. Did you overheat it at one point? If you did, you probably put that engine to sleep. Nighty night.

 

Hey Po,

Interesting topic, I was just kicking this around on another thread.

Have you seen many 4.2 failures? Any particular patterns to look for? There was one guy on here who lost a primary chain when one of his intake cams seized at the front journal. Is that one you have seen/ heard of? Thanks, from outside the loop.

Andy

 

The only time I've seen the 4.2 die is when Mr. Customer develops a coolant leak; ie: reservoir, thermostat housing, or water pump, and he keeps on truckin'. Well you know the end result.....she eventually relents, and the party begins. Knocking, or I've even seen a complete, and yes a complete meltdown of the engine. I mean hot enough to not only melt the intake manifold and wiring, and everything else plastic including the tanks on the radiator, but the friggin heads, and block were beginning to droop like......well use your imagination.

The 4.2 is pretty sound, IF you keep oil in it, and that cooling system is tight and right. They don't hold much coolant. Other than overheating or no oil, meaning lack of service, great engines compared to the 4.0.

 

Cool, thanks for that. Even an AJ16 engine can break if you treat it badly enough, it's good to know these are holding up as well.

So would you care to offer an explanation for your choice of avitar?

 

I'm a wise guy I guess, and a bit of a smart ***. Hard to see the sarcasm/humor on the net. I've been using that one for years on other forums.

 

Up to the high revs, the engine pulls fine and is as quiet and smooth as ever. Can still lay rubber with the DSC off. The temp gauge has never risen above the mid point. 12000 miles ago, last winter, one of the intercooler hoses let go - the engine was shut off within seconds and the car was carried to the nearest jaguar dealership. They replaced the hose, replaced the lost coolant - only about a litre - and deemed that all was fine. And all seemed fine until about 3000 km ago. Engine doesn't consume or leak any fluids. Coolant is orange and oil is oily without any grit or metal - Castrol Synthetic - and never older than 4 months or 5000 km. Starts and runs fine until I run really high revs (which I obviously have been avoiding.) Restricted power light has not come on since. Fuel economy is slightly better since the plug change.

 

Ok, but you still have a knock. When you say "can still lay rubber", sounds like you drive it hard, eh? Or no? Take it somewhere, have it checked out. Nobody can wave a wand at that noisy engine. And it sounds like that's what you expect. You repeated yourself with your second post, so I'll repeat myself, too. Without looking at it, which someone will need to do, it sounds like an engine failure to me. But again, just a guess over the net without listening to it. Could it be other stuff? Sure, and I mentioned those, too.

And you telling me there was a hose that let go, I would bet it overheated. You say you shut it off within seconds? Well I hate to tell you this, but EVERYONE says that very same thing when they blow their engine. Sure the hose failed, but no one really wants to admit that it was them who caused the meltdown, but 99% of the time, they keep on truckin'. Most don't pay enough attention to what the car is doing. And most of them always blame Jaguar.

 

Thanks for your input. I was hoping someone had a similar experience and could offer constructive insight into diagnosing the problem. It was no more than 10 seconds to stop the car and turn the engine off upon the smell of steam - and this was while the car was crawling in traffic about 15 minutes into my trip on a cool winter morning where the temp indicator never got higher than the horizontal. This was also 20000 km ago! Is it normal for a engine that has "failed" 3000 km ago (when restricted light came on for the first time) to run quietly and cool at 80 mph on a 100 degree day with the AC full - with no warning lights?

 

Further, I plugged in my OBD II scanner again today - no codes.
Before the spark plugs were changed about 400 km ago - there was a misfire on #8.

 

Well the 4.2 in general is pretty tough. In the 7 years this engine has been out, I have had the pleasure of replacing only but a handful of these engines. All of them were from lack of maintenance or overheating. So my examples are similar to yours, even though you say you shut it off right away. I'll take your word for what you say, but you still have a knock and therefore should be diagnosed before real damage occurs. Who knows, it may be something minor!

 

Similar issue with my 2002 S-type 4.0.

I had a check engine light come on. A day later I started hearing knocking under acceleration. I took it into the dealer that day. They took 3 days to get back and said the believe the rod bearings are shot and that the car is 4 quarts low on oil. I had had it in for the 50K service late december and again later in december had the valve cover gaskets replaced due to an oil leak. At that time (12/30) they said no leaks, everything was fine. So how does the car go from that condition to 4 quarts low on oil in 6 months and less than 6000 miles? BTW - the temp looked fine, no noticable loss of power.

 

Delete.

 

A 4.0 can easily burn through a quart in 1k miles or less! I've seen it many a time. It all really depends on how you take care of it, or have taken care of it, if you are the original owner. If it's been overheated, even once, she'll burn oil. And the way these older S types are being taken care of these days, I'm not surprised at all you've burned 4 qts. in less than 6k miles. Normally, one would think you'd check your oil level at least 2 times a month. We know you are not doing that for sure. Or you would have noticed your oil loss way before 4 qts were gone. Now if it burned 2 qts, in say 1 month, and around 1k, I'd be more concerned. But you are burning 1qt. maybe a bit more per month. I wouldn't worry, I'd just check my level more often, or in your case, start checking it.

Have you had the knock fixed? What was the outcome of the knock? That'd be the more important issue, and what caused that.

 

Ultimately you are correct. By your description I should be checking the oil daily. I figured since the car was under the reccomended maintenance schedule and is a premium brand, i was doing fine. I've had cars where I knew to check oil regularly - my 65 mustang, my 82 toyota pickup. Even in the worst of times none of them lost 4 quarts of oil in 6 months. But I digress. Jaguar corporate said they will do nothing. 63K miles and the engine is dead (bad rod bearings according to the dealer) and they want $14,500 for a new engine. I'm not going to spend that money on a car that goes for 5-7000 at auction so I'm not sure where to go from here. I wonder if carmax will by it for parts. I love Jaguar styling and performance but this will be my first and last Jaguar. I appreciate your comments. BTW - I'm going to check my oil weekly on all my cars from now on.

 

Man - I have the same problem with my '04 XJR. I started a couple of weeks back - slight loss of power at about 4500RPM and then it fgot gradually worse and a 'rattle' developed. It now loses power at a little over 3000RPM - To it to the Jag dealer - worth mentioning at this point there was no engine management light......They said it was a fuelling problem, and a software update foer the fuel management system should cure it - ran the update - no error codes stored......problem still there - I had recently fuelled the car so they suggested that it may be bad fuel and to reun it empty and then fill up somehwhere else as it was definately a detonation problem.....so....still the same problem - to it to a local garage and had the spark plugs done - now I have the engine management light and same problem - no error code tho??? Someone suggested it may be the CAM Sensors or a knock sensor......any thoughts?? If it was bad fuel, could it have wrecked the Llambda sensor? - did u get yours fixed BC04XJR ??
Cheers Guys

 

Worth noting - I've been running this car for over a year now, and haven't had any prior issues with the engine, and it's never overheated or blown any hoses....

 

Wow - just taken the Jag round to a firend at another garage, and hey presto - fault codes - they seem to point to a problem with cylinder 3 on bank 2 - funnily enough - that's the one that had a slightly carbonised spark plug - seems like maybe a faulty injector???? - also mentioned about the pinking, and he suggested it may be something realted to a scondary throttle body sticking - so do I maybe have two problems here?

 

Aha - just an update- I got my problem fixed.....found this very knowledgeable guy......suggested it may be the CATS causing the pinking (rattle at higher revs). He says that in the XJR the CAT material is prone to melting!.....so - took the car to my local garage, who cut the cats along the seams, and removed the internal element, then re-welded the cats and put them back empty - car runs like a dream!!!!! - sounds like a bag of bolts tho lol, but that will all be sorted when the new cats go in. Hope that helps....