Greetings everyone...

I sincerely appreciate your advice on the following two issues - as a "newbie" XJS convertible owner [Relevant background info: My car has almost 51,000 miles now (1992, 5.3 v12 - Marelli). The last owner put only 800 miles on him in four years and I truly believe the only "maintenance" has been oil changes (from way back - before the last owner). I have replaced the air filters, oil/filter and coolant...along with two new thermos and an auxiliary fan temp sensor - plus Wetter Water, of course! - the new parts are the ones that kick in/on quicker than the original/stock parts. The car runs *noticeably* cooler now even though it never went over 1/2 on the temp gauge before.]:

1. Marelli distributor cap/rotor (and coils) + plugs/wires? The car starts and runs very well. The distributor looks clean from above, as do the wires. Should I go ahead and replace these items anyway? I have read about the fire issue and that really concerns me! Again, I'm assuming nothing much has been done before.

(If you recommend this maintenance, please kindly provide some relevant pointers from your experience - I'll be doing the work myself. I see that some parts (fuel system) will have to be removed first and, further, some of the plugs look like a complete mess to get to and remove? I think I have a special Jaguar plug remover tool in my trunk - it looks like one?)

2. Transmission/gearbox fluid change? The transmission fluid looks very clean and the car drives very well. I'm considering letting my local Valvolene place do it with their fancy machine (as I did with my Jeep Commander). Thoughts? I know the guys and I'm right there when work is done by them. It should be a really simple thing given the fact the transmission is standard GM?

***Please feel free to give me any other thoughts/suggestions you may have.

Many thanks to you (and our group moderators/sponsors!)

Jerry

 

I'd replace plugs and wires. Remove and inspect distributor cap and rotor, replace if needed. Specifically....how do the dist cap contact points look? Is the rotor scorched? If in doubt, replace both. Consider the dab-of-silicone-under-the-rotor trick.




I'd go with the fancy flush machine.

The simple-ness factor of the flush process depends on the accessibility of the cooler pipes at the radiator......which is fairly good as I recall.

The old fashioned drop-the-transmission-pan method is not especially easy on the XJS despite having a prosaic GM transmission.




What about changing the differential oil and brake fluid? Both are often overlooked....as is repacking the front wheel bearings.

Cheers
DD

 

The easiest way to change plugs is to incorporate the task in the larger job of "doing the vee". That means removing the plug wires, fuel rail, throttle tower, cruise control....clearing out the 'vee' of the motor to replace fuel hoses, replace vacuum hoses, repair crispy wires, clean and synchronize the throttles, replace throttle bushings, etc all in one fell swoop. Pretty big job...but you're getting everything done all at once.

If you don't wanna go that far then just remove the cruise control servo and throttle tower....and shift-aside (but don't remove) the a/c compressor for access to the forward spark plugs.

If you don't wanna go that far then be ready to do battle. You can get all the plugs out without removing anything. You won't like it one little bit, but it's doable

Cheers
DD

 

Doug has nailed it.

I was going to stress ALL the fuel hoses, and the plugs at the same time.

Removing stuff for cleaning out the V BEFORE removing any spark plugs is mandatory, coz there will be "stuff" in that V that will simply fall INTO the spark plug hole, and that is fact. I blow it out with comp air, and vac, then blow again, and ONE sparker at a time, so the engine is not left open to temptation.

The 2 front plugs are a mongrel at any time, so be prepared for that litle escapade, and they are probably siezed in there.

 

Many thanks for your detailed replies...very helpful.

Those two plugs sound interesting to say the least. I recall one American car (brand/model?) where changing one rear plug required removing the entire motor! Crazy!

Question: is that funny looking tool in my jack kit (which doesn't fit a lug nut) for the plugs?


Thanks again...

 

After buying my 92 with similar mileage to yours and while it was already running well, I replaced the plugs/wires and checked the distributor and rotor. Ended up not replacing the rotor or cap but I check them periodically for condition as Doug noted. I used Magnecor 8.5mm wires.

At the same time I took the opportunity to replace the fuel hoses. On the 92 and later it's a smaller job as they don't have the 12 short hoses between the fuel rail and injectors. There is just the feed hose, return hose and 2 crossover hoses between the fuel rails.

I chose to move the ac compressor (don't undo the ac hoses and lose your freon)out of the way to get to the front plugs. I didn't even want to attempt it without moving it but some people do. I also unbolted the throttle pedestal for ease of replacing the plugs at the rear. I used some crowfoot Sockets to get to the pedestal bolts. I replaced a few vacuum hoses along the way as they appeared worn.

I just took my time on the job and cleaned the vee as access opened up. Very satisfying when all done.

Regarding moving the ac compressor: there was a design change at some point prior to 92. There used to be two bolts at the bottom rear of the compressor holding it to a bracket that is then bolted to the vee. You could remove the bolts then the rear of the compressor could be lifted directly up and out of the way.

On my 92 there are 2 studs exiting the rear of the compressor, holding it to the bracket. So you remove the nuts from the studs and then the compressor has to be moved forward so the studs can clear the bracket before it can be lifted up and out of the way.

Unless I just missed something, the compressor can't be moved forward enough unless you remove the front fuel crossover hose, which is another reason to replace that hose while doing the plugs. If the crossover hoses are original they are a bear to get off. Use a very sharp exacto or similar and don't score the fuel barbs.

I agree with using a vacuum attachment and/or compressed air to blow debris out of the area before removing any plugs. They are recessed a bit and tend to catch a lot of dirt.

Although the car was running well before this work it seemed even smoother afterwards. The V12 is sublime when running well.

 

Question: is that funny looking tool in my jack kit (which doesn't fit a lug nut) for the plugs?



Yes, that should be it. I would spray the plugs with pb blaster or similar before trying to remove them. And use anti seize on the new ones when putting them in.

 

Extremely good advice everyone...thanks. I'm not going to lie - the fuel rail makes me nervous...going on the old notion learned from my dad: "If it ain't broke, leave it alone!" - but, I also fully understand how this machine requires a special thought process with the Marelli issue, etc. By the way, my "V" area and everything else looks show-room new and clean...but, looks are often deceiving! When I replaced the passenger side thermo, the lower right housing bolt snapped right off! That fellow was a chore to get out with heat. The housing now has 4 new stainless steel bolts. Thanks again...

 

I agree with the mind numbing plan ahead.

First V12 I did was a 1976 PreHE, and they are fun, NOT.

The fuel hoses will leak, and since that guy "Murphy" resides inside the V, they will spray fuel ONTO the distributor cap, and BBQ Jag follows extremely quickly.

That odd spanner/wrench is more than likely the spark plug tool, and I have never worked how it is supposed to get the 2 front plugs out without moving tha compressor anyway, and cracking the porcelain bit of those plugs is sooooo easy if the "angle of the dangle" is out just a bit.