Low compression on V8

[robv12]

do NOT buy a diesel for the journeys you are doing, it is totally the wrong car, a 3.0 will be as quick, as economical, and cheaper to maintain, as Mike says I have a 270K miles 3.0 that runs like a swiss watch, I also have a 161K TDvi that I have done 42K miles in over the last year and it has been the most expensive and troublesome car ever, even beats my Maserati QP on costs, and, this is with mainly long hauls, short journey diesels, all makes, not just Jaguars are a liability due to problems with the DPF blocking. Just ask Eddy at EuroJag how many 350/358 burnouts they get in, 15 last week when I was there.Just google, "diesel runaway" and be prepared to be very scared, imo buy one on IoM at your peril

[ptjs1]

Neil,

+1 for not buying a diesel for use on IoM.

Just did a 100 mile run yesterday in my 2004 4.2 SE. 70 mph for 45 miles and then stuck in stop-start M25 for the rest. Returned an accurate 35mpg!

With the price of a 4.2 more attractive than a 3.0, I'd get another 4.2 if I were you. Mind you, I'd still be throwing a few tins of Ametech in now just in case it might cure the problem!

Good luck

Paul

[ManxNeil]

Well, that's definitely not a diesel, then! All advice was appreciated. The replacement of the V8 has had to be put back a week. I've purchased the engine from Eurojag but they are very busy and can't guarantee delivery to XJK by this week. Next week is Manx Grand Prix race week and all the ferries are fully booked so the earliest I'll be able to get over is the following Monday.

There is a local engineering company which has a very good reputation (i.e. not only is their work good but they're honest and open about whether they can complete the work to the required standard) and which, crucially, the mechanics at the IOM Jaguar agent seems to respect so I might get them to have a look at the existing engine when it comes back, initially to determine precisely what went wrong. I'll post any findings here but I'll be holding off on the Ametech for the moment - unless the replacement engine is also low on compression!

Throughout my time with the car I've also been pleased with how comparatively economical it's been, fuel-wise, even under local conditions.

[robv12]

I understand the wish to use a local guy, but please do bear this in mind, the engine swap on these cars is easy enough with the right kit, XJK have this and have done many engine out jobs, including two for me. They understand these cars. once the new engine is in, it will need to be "configured" to the car to get it to run right, again XJK have Jaguar SDD to set this up

I have no connection with XJK, apart from spending huge amounts of my hard earned with them, but as a testament to their work I take my cars from Edinburgh to Stoke for them to look after, I rest my case!!

[ManxNeil]

XJK will be putting the engine from Eurojag in in the next week or two, Rob. As to the future, if I were to have the original engine rebuilt then I would probably be getting either the local Jag service agent or XJK to do the second swap. The engineering company I mentioned would only be working on the engine on the bench, they wouldn't be installing it.

Cheers,

[barrywi]

HOWEVER........maybe the IOM is the wrong place for a diesel but in my experience of running one over 5 years mine has been trouble free. I am not sure what special tools are required for servicing ?? but it is possible to do an oil and filter change without going under the car. Lift off the plastic engine cover, remove the oil filter which is between the V of the engine, suck out the old oil with a pump through the dipstick hole fill up with new oil and fit a new filter. Replace cover and the job is done. The more expensive services just involve pollen and air filters, just like any petrol. New cam belts etc are at around 90000 miles. The rest of the car is mainly the same as the petrol.
Servicing costs at my local Jaguar main dealer are on a par with those of my previous Peugeot 407 diesel, the only difference is that nothing has gone wrong with my 350 unlike the Peugeot.
My car has done mainly short runs, but I make sure I do a longer run every so often and that is the only special treatment it gets. MPG goes from about 35 when the car never gets into top gear up to a realistic 44 on motorway trips. It has loads of low down torque and is fast enough for me. It is not even noisy even compared with petrol. No,diesel smell either.
Even the dreaded DPF ,which I have never touched or even put additives into the fuel to keep it clean , may be expensive if you do need to replace it,but you save on road tax every year compared with the V8s in particular.
The horror stories mentioned by DM at the seminars seemed to me to originate mainly from poor maintenance.
Just an alternate view based on personal experience...I bet the engine will blow up tomorrow!!

[ManxNeil]

Here I am staying with friends in beautiful Wiltshire while the Jag is up with XJK in Newcastle-under-Lyme and the news from them is that the engine does NOT need changing! They identified a breathing problem which is now sorted and report good compression on all eight cylinders. From talking to them when I dropped it off on Tuesday they were immediately dubious of the local agent's diagnosis and decided to carry out their own investigation before pulling the engine out.

That's the good news. The bad news is that they've condemned the gearbox. They weren't satisfied with the changes and have also attributed 'hunting' between 1,000 and 2,000 RPM to the 'box. They've tried to see if they can fix it, but no dice. Fortunately, Eurojag have agreed to swap the now unrequired engine I bought for a lower mileage gearbox and, all being well, it will be going in today.

While it's at XJK I'm having a few other suspension issues seen to - a new nearside air spring to replace a leaking unit and various bushes and a balljoint. They're even fitting two new Dunlops cheaper than I can get on the IOM. I'm hoping to be left with one of the best-running 350s for its age.

Obviously, I'll seek to obtain as much technical detail as I can around the apparent mis-diagnosis and the fix carried out by XJK, together with what the problem was with the gearbox, and post them up when I get back home at the weekend.

Cheers,

[ptjs1]

Neil,

Good news on the engine! It's restored our faith in the belief that those V8s are really very good even at high mileages.

As regards the gearbox: it may be too late for you, but I had great results just from a reset of the software adaptations which resolved a harsh change that I sometimes started to experience between 2nd and 3rd. Adaptation reset is also a suggested approach to cure the hunting problem. I'm a little surprised that XJK didn't at least suggest that approach first?

Cheers

Paul

[ManxNeil]

Thanks, Paul. Yes, I'm ashamed I ever doubted the engine but an e-mail from David Marks questioned the procedure the local garage followed to get the poor compression results.

With regard to the gearbox, XJK did tell me they'd be examining all electronic and mechanical fixes before calling for its replacement. When I complained about the 'hunting' back on the IOM some years ago, I know that the adaptation reset was carried out then, to no avail. As the 'hunting' only lasted for a few minutes I lived with it. Again, I'll try to put as much information as I can obtain up later.

Cheers,

[J44EAG]

In my experience and that was some years back before I got my teeth into maintaining my 4 litre V8, I had a slight hunting issue at idle speed.

I then cleaned the throttle body throat and butterfly valve with carb cleaner and the problem disappeared. Might be worth a look to see if the throttle throat has a build up of crank case breather gunk on it. The gunk will certainly restrict air flow at idle speed and possibly cause the stepper motor to keep opening the throttle plate to keep the engine running as smoothly as possible under clogged up situations. Just a thought.

Mike K

[ptjs1]

Just to add a slight word of caution to cleaning the throttle butterfly:

It used to be a de rigeur procedure on XJSs & x308s, but I'm not so sure on 4.2 x350s. I cleaned mine a few years ago and ended up with a fast idle that took over 3 months to settle down. I spoke with XJK and they advised against cleaning the body on x350s, saying they ere too sensitive. Have a word with the first.

Paul

[ManxNeil]

Unfortunately, the replacement gearbox has been found to be worse than the first so the car will be staying over here with XJK for a week or two while they source a better one and I'll have to fly home without it. It's frustrating because everything else has been done and it looked as though they'd even polished it.

I spoke to them about the "low compression" yesterday and, though they had identified another breather that wasn't properly attached, together with the possibility of oil build-up around the MAP sensor, the final comment from the technician was "If anyone tells me they've found low compression on a Jag 4.2 V8 with reasonable mileage, my inclination is to tell them to replace their compression tester!"

[ManxNeil]

Just to finish this one off, I collected the Jag from XJK A week ago, having bitten the bullet and had a brand new gearbox fitted and a load of suspension bushes, arms and an air spring replaced. It now drives like new and I have renewed confidence in it. I know it makes no economic sense, but what the hell - I love the car. Next jobs will sorting out the kerbed alloys, refurbishment of the driver's seat and getting the worn leather on the steering wheel recovered; the recent expenditure means I want the car back to looking as pristine as possible!

Having discussed the original complaint with Gavin and the guys at XJK and reviewed the itemised invoice, it basically came down to a poorly fitting breather that caused the alarm bells to ring. It's disturbing that the local garages could have got it so wrong. On the positive side, I was very impressed by XJK and would recommend them for their professionalism and friendly manner.

Thanks to all of you for your responses and advice.

Cheers,