i have a jag xjs v12 1989 with 31,000 miles on it, its a 2 seater convertible, basically my grandad brought it from new and about 9 years ago stop driving it due to somone telling him in a garage it needs a rebuild as there is oil in the coolant, im a tech my self but dont no much about these cars and its still sitting over his garage and i would love to get this up and running again no matter what it takes i have done alot or searchin about these cars about them having cooling trouble, now im starting to think due to me working for vauxhalls that a engine that size and that low milage i cant see why the headgaskets would have failed, the guy he tok it to was rebuilding a simlar engine on a aston martin and said its common due to the lack of use, now i think thats rubbish as he always had it serviced ect, i no it never over heated, but i found out about the rads being a let down and also no the tranny rad shares the same as the coolant rad its possible that the rads gone and theyve mixed ????? what are the common faults and how could i be so sure i dont want to have to start taking the sump off checking bearings ect to check for damage if the coolant has got in the system, or maybe the oil coolers gone and mixed the coolant with oil and made it look like a headgasket, but he did say that he remembers when he drove it back from that garage 9 years ago the light came on and it didnt start again, i dont no about the managment system on these but could if have been a warning light and it needs clearing to be safe before it fires again, as i know its a old car but heard its got a clever managment system like modern cars

hope somone can help me the car is mint and im 22 and i would love to get this up and running my plans are to go change the coolant change the oil and battery and try fire her up and go from there and see what faults happen then

 

After all those years out of action, you really do need to "recommission" the car. This will involve replacing all fluids: -

- coolant
- engine oil
- transmission (gearbox) oil
- differential oil
- brake fluid

when you drain the coolant you will see if it has oil in it. If it has there is likely to be coolant in the oil as well. I don't know if the XJS had this feature, but my old '80 Series 3 XJ6 had a transmission oil cooler/warmer which was a large diameter pipe below the radiator with a small "radiator" built inside it for the oil. The coolant warmed up the transmission oil when cold and then cooled it to coolant temperature. In effect it was an indirect cooler, and clearly the heat removed was dumped by the main radiator.

Corrosion inside this pipe due to coolant not having been maintained correctly, i.e replaced at the correct intervals, meant coolant and oil could get mixed up. As the coolant was under pressure, and the oil was not, the coolant got into the oil, more than the other way around. I did not suffer this problem, by the way, I just read about it many years ago.

If it is engine oil in the coolant, it sounds like a cylinder heads off job to me, as that is normally a head gasket failure can cause mixing of the two

Don't forget to re-commission the brakes, and check for efficiency.

Tyres will now be out-of-date and must be replaced.

I recently did a similar exercise with a 1977 MG Midget with 22k miles off road for 16 years, but I expect your car will cost more to get back on the road !

If you do everything properly, you should have a peach of a car; an XJS convertible in excellent condition will be worth something.

 

The trans oil-into-coolant scenario is possible as the transmission coolers (inside the radiator in this case) do occassionally leak. In this case the oil in the coolant might still appear to be reddish.

Engine oil in the coolant does suggest a head gasket problem...not unheard of of on a V12 but not as common as, say, the old 4.2 XK engine....where head gasket replacement was almost a routine serive item at 100k miles.

Beside Fraser's reamarks, which I agree with, if there's no coolant in the oil I get the old girl fired up and see what happens. A hydro-carbon test would confirm a blown head gasket.

How do you know it never overheated? The radiator is segmented 1/3 to one bank and 2/3 to the other bank which can cause flow problems.....which can cause steam pockets and localized overheated if if nothing shows on the temp gauge...which, by the way, only reads from the right bank.

These are great cars but you have quite a job ahead of you. Shout back when needed. There are many here who will help.

As an aside I'll mention that postings with so much information in one v e r y l o n g sentence, contained in a single giant paragraph, are very hard to slog thru and understand, at least for old farts like me. No insult intended, mind you.

Cheers
DD

 

thank you for your replys guys means alot i want to get this done its in such good order not one bit of rust its been garaged all its life since day one would love to get it up and running again ive seen the high prices these motors are worth and shocking but then again its a classic and well worth it, more to the subject my grandad is dead sure it didnt over heat on his way back from the garage now i seem to think it can still be the trans oil with the coolant, a guy looked at the car with in 5 mins and told him it need a rebuild now just looking at the coolant coz theres oil init doesent mean it needs a rebuild surly maybe head gaskets, but i know for sure it didnt over heat, and hope it never does i dont want stems droping lol,i just wondered if the oil cooler could have failed on these and the gaskets let go and let oil in with the coolant as most cars there normaly linked somwere with the coolant, but as said before i found out that the coolant rad is also the trans rad and its a standard 10 year old rad at the time it happend it coould have givven now as these have problems with cooling when i hopfuly find the problem and get it up and running i will buy a direct ali rad ive seen with 40% more cooling, hopfuly when i go to see it i can flush things and have a look but to be honest im not used to big engines like this i work at vauxhall were the biggest we have these days are v6 2.5-2.8 lol so half the size just doing a service on one of these looks a bit tight and also heard the plugs are a bit tight lol joys of a jag aye lol

 

any more ideas or info on what else i should do to check or common faults thanks dan

 

Dan, did you read Doug's comment about trying to slog through one long, long sentence with no breaks?

It makes reading all the info', very hard on the eyes. To the point where I didn't read your second post in this thread.

Please at the very least include some double line breaks every now and then.

The guys will be much more likely to help you.

 

I'm ignoring all of the above and assuming this this is your question:


As already mentioned, the transmission oil cooler and leaky head gasket are both plausible suspects.

If you are now referring to the engine oil cooler I'd have to say "no". Although they do fail from time to time I can't see where it would cause your problem. Unlike the liquid-to-liquid transmission cooler the engine oil cooler is the air-to-liquid type with no cooling system tie-in.

I'd change the oil and filter, flush the cooling system and get her running....and go from there.






So....quit yappin' and get to work ! :-)


Cheers
DD

 

Richard,
I originally didn't read the second posting either but then felt a bit guilty and decided to have a go. After 10 minutes of parsing I was able, I think, to find and address Dan's question.


Dan,
I hate to sound like a pr*ck but it's just too much work to read and understand your postings as they are written. Perfection is not expected or required (just look at my postings...heh heh heh) but, really, if you could come to the point more quickly and break things down into sentences and paragraphs it would be a big help.


Cheers
DD

 

Yeah, I can only reinforce what Doug is saying.

Remember, that most of the time, the guys don't have half of the time.

I couldn't give a Panda's sneeze about correcting Grandma, or Punk Tuition.

It is what you need to say that is important.

And that we can then reasonably reply to you.

Just please help us more mature (read old farts) guys out, by not using 'text' settings for posting here.

 

oh no its no ones fault but mine,

sorry im new on here and im used to the toyota forum as i have a little starlet turbo glanza aswel,

but i would normaly space it out but the keep boards enter buttom broke lol and would be a night mare to just hold space down, got a new one now so its all ok

but yeah thats the question its hard i would just to get on to it and have a look just wondered if any ones got a personal idea of what they think could have happened,

last thing i want to do is a full rebuild top to bottom i think i could just about manage head gaskets with a beer to keep me carm lol as its a pretty big job on a v12 lol

once again sorry guys

 

Hi Dan, thanks for getting back to us, we are all good now.

As Doug said, try to get the thing running with new fluids etc, and see what you have to deal with.

Keep a close eye on the fuel lines after a decade of sitting they may be in poor condition and if they let go you could be looking at BBQ XJS.

Good luck.

 

hey thanks for your help guys

and yeah im gonna start next week by flushing it all with new fluids with just water not coolant to save money then when i no whats going on it will be coolant,

also flush the fuel tank its been sitting 9 years

so old fuel and i will crack off the fuel feed pipe and drain the old fuel and pipe the new fuel up then do it up hopfuly be fresh fresh,

but really hoping its not headgaskets lol but if water is in the oil how long does it have to be in there till it damages the bottom end shells ect

thanks dan