OK, I'm back (Merlot glass is FULL) and I have been reading all you have written so far, and I have a few suggestions based on my V12 experience over tooooooo many years.

Head gasket failure, albeit rare, can happen. These V12's are TOUGH suckers< EXCEPT when they get OVERHEATED.

IF, and I mean IF, the oil still likes like oil, then a simple oil change after the head R&R will suffice.

However, IF that oil is like a coffee cream, then a FUL oil gallery flush will be required, only YOU can tell that one.

I am assuming (hahaha, I love assuming NOT) that the oil is OK, coz you have not answered that one yet. SO, based on that, IS IT A HEAD GASKET.

My reasons for saying that are:

At the rear of the LH head you have 2 heater hoses, and if they are NOT fitted correctly (by that I mean your mouth was at the wrong angle on that day), they will rub on the oil pipe banjo bolt, and "green blood" will eventually spew profusely, mmmmm.

Engine gets REAL HOT, oil pressure drops, as do valve inserts (hence the clatter you mention).

Also at the rear of the LH head you have the AAV unit, which has a gasket to keep the "green blood" inside the engine, and it can blow, VERY unlikely, but it is a British non-metallic item. That will also give you the spewing you mention, and the HOT engine, and the clatter from valve inserts dropping.

Just toward the centre, but still to the LH side, is the heater tap, and it can/does fall apart, and "green blood" spews etc etc.

Just under the master cylinder (I know LHD, I have read your location) is the metal pipe that returns heater coolant to the radiator, and the hose attached at the top is just near the LH corner of the LH cylinder head, and being a hose it can rupture from old age??.

Since you have "clatter" you have dropped valve inserts, ( #5B & #6B will be my guess) and the 2 cylinder heads SHOULD come off, and all 24 inserts replaced, and whatever bent valves replaced. The cylinder heads should also be tested for hardness, COZ THEY GOT BLOODY HOT, and may be throw away units. I know this is NOT what you wanted to hear, but them is the facts with an overheated HE V12.

Have a good look at the items I mentioned, coz when you take the heads off, and do all that work, the REAL reason/s for the failure MUST be found.

Being LHD the master cylinder off would make sense, and from what I have heard these heads are a mongrel to get off in situ (as already mentioned). On the ones I have done I simply take the engine out, do the oil filter o/rings, oil pipe o/rings, reseal the liners, and generally clean/tidy the engine bay, and NEVER touch the thing again. Do it ONCE, do it PROPERLY.

The timing chain tensioner also worries me. You will have to release it, and it is plastic, and has got HOT, and they are known to snap under those conditions.

I run twin thermo fans on all the V12's, and have done so since 1996, and NEVER ever get temp problems.

 

u scared me for a second before i read "(metaphor)"

 

thanks for all the info grant im sure its going to be really helpful. When i get my car inside and the hood off Im gonna take a couple pics and post them to see what everyone thinks.

I really haven't dove into it yet, i opened the hood after it broke down and looked around but I haven't actually looked to see where the leak was from or anything.

Like you said they should be taken off regardless of the reason and my gasket set DID get in today.

im hoping the damage is minimal obviously.

luckily my dad worked on e-types in the 80s and can help me out when he has the time.


whats really weird is i have seen the temp gauge max out before and that day it was at maybe 3/4. ( I know this is HOT but just sayin).

 

hey just to be clear valve "inserts" are the same thing as seats or guides right? just wanna make sure we are on the same page but i can't think of anything else you would be talking about

 

HAHA, I keep forgetting we Aussies "talk funny". I get that all the time when in Las Vegas, and I milk it for all I can get.

Yep, "inserts/valve seats" ALL the same depending what language your side of the pond speaks.

Valve guides are the metal "sleeve" looking things that the valve stems slide up and down in when the valves open and close. Not normally a severe wear item on the V12, but I ALWAYS replace them when I have a V12 apart, it is just waaaaaaaaay toooooooo much work to NOT do them.

I am interested in that "clatter" you mentioned, that you seemed to think was lack of oil pressure. The tappets (lifters) on the V12 are "solid type" and would NOT clatter as such.

I have a Pre HE (hers) that had a sqeaking sound from up top, took some serious finding, and it was incorrect copper washers on the 2 banjo bolts at the rear that feed oil to the top end, and effectively blocked the oil supply, NO clatter, just this wierd "sqeaking sound". New washers (proper type), and silent as expected. This engine has now done 497000kms, and still runs sweet, leaks oil (who cares), loves the fuel (so what), starts and stops on demand (priceless), and since its "Hers", it MUST be reliable (nag nag nag).

Since you have seen "max temps before", sounds like the cooling system is a tad out of whack, and this spewing of fluid is the end result. It does sound like this engine has had some hot running punishment.

So that engine really should come out and be stripped and refreshed internally, the radiator sorted (professionally), new thermostats (correct length), ALL new hoses and clamps, etc tec.

 

off topic but what kind of fuel mileage does it get. I ALWAYS hear ppl say stuff about gas mileage with the v12 but honestly i have nothing to complain about.
a v12 in a 2 ton car that looks that good getting 18-19mpg is fine by me

 

Since you are up there and gallons are less than ours, and we use litres now anyway, you can do the cross calculations.

The HE does 15+/- L/100kms around the suburbs, and on interstate trips, the last was 8500kms, it averaged 11.2L/100kms.

The PreHE, NO BLOODY IDEA, never looked, it would be scary, just keep pouring it in, about 200kms per 45ltr tank in the suburbs, and 320kms per 45ltr tank on the last run we did in it many years ago.

 

I used forklift to get my heads off few years back. I remember entire car hanging on the damn heads, before they would slide off

 

daamn man thats ridiculous...this isn't sounding good lol.

btw grant thats around 18-19mpg which is what it should get, to me thats not bad for what these cars are. 15liter per 100km would suck though.



so to be blunt...what do I do about the timing? The only overhead cam engine i have taken apart before was just to get the engine out, it was scrapped.
Do i just try and grab it at the balancer and put it in tdc and then later... Well i guess there is something indicating where the cams should be at when its tdc so ill be good?

also..i supposed i should be adjusting and re-seating so theres no point in measures clearances right?

 

also grant about to get into it and still really hoping its not actually blown....do you really think the clatter would be inserts because it was only at a higher rpm so maybe its was just being noiser from lack of oil?

 

this is looking less likely to me tbh. I have never seen a blown headgasket that literally blew coolant around for one (okay im 19 and have only seen a handful but still).
Im having trouble tracking it since it blew up onto the hood and came back down, I understand this coolant was under alot of pressure but still...

There is some oil around the banjo fitting and half moon seal but its really dirty and just looks like typical slow leak from age (my oil is very clean).

i understand it was hot but it has been maxed out once before and the oil pressure didn't drop. Maybe since it can max out the temp gauge it was hotter than before but obviously i didn't know to what degree?

So is it possible from the heat that I blew a coolant line and some oil fitting at the same time?

i don't wanna make this too wordy and deter people but ijdk.
I DID start it to get it up the ramp into the shop, it sounded COMPLETELY normal and i did have to rev it (didn't see where to since i was lining it up).

should i turn it on and check oil pressure and see if coolant leaks?

 

yeah idk how the hell would a head gasket do this?




i cld be wrong but i made this thread when i hadn't looked at my car at all and I haven't up until today, but because of the symptoms I assumed the worst.

as you can see its pretty greasy around that coolant line but thats not a blown line, oil going everywhere leak. Also the insulation on that line is coming off and it obviously gets hot, but i dont see where the coolant came from, maybe it blew through a fitting because the pressure was high enough? The spray spans from the valve cover to the master cylinder.

 

just put water in it (tried) its leaking in this area down onto the exhaust and ground. So i guess it could be the gasket but maybe its a line over there. about to jack it up and look around.

 

its the lower heat hose!!!

wow what a ridiculous bunch of crap to get it off but at least its just a hose! I had to get a razor blade down in there and literally peel it off the heater core.

anyone know the name for this hose? I have removed it probably 5 times already so it finally broke. its called the air balance elbow or hose right?

 

OK.

One thing at a time.

That hose in the second picture is the "balance pipe" hose, and is NOT coolant, or oil related. The engine will have a MASSIVE vac leak, if it ever started. So that item is NOT your oil or coolant issue. I use genuine hoses ONLY.

The lower heater hose (going INTO the heater core) SHOULD be the heater INLET, meaning that hose comes from the heater tap to the core. Some are plumbed the other way, and it possibly makes little difference to heater performance. I only use genuine hoses here, and I would be replacing the 3 heater hoses and the heater tap, you have all that stuff off, so do it once, do it right, leave it be for 10 more years.

The 2 top radiator hoses, the bottom radiator hose, and the heater return hose at the connector for the bottom radiator hose AT the radiator should also be replaced. Basically I am saying that ALL the coolant hoses should be replaced, and there a many more over and above what I have mentioned previously.

The radiator caps should be replaced as a matter of course (my opinion).

The fact it has got SO HOT, I would be pulling the radiator and getting it professionally flushed/rodded, coz at those temps you have stirred up a whole pile of crap in the block and dumped it all in the radiator. The banjo fitting in the RH top of the radiator and the pipes attached to it should also be checked for blockage. The header tank removed and flushed out, it will be full of crud.

The thermostats MUST be replaced, they will be toast after so much heat.

The list goes on, but basic common sense will see it OK.

The fact the engine "sounds" OK, is a blessing, and you may have been LUCKY.

The V12 engine is near on bullet proof, EXCEPT when it gets overheated, and it sounds like yours has got hot a few times, so now is the time to fix it, and fix it properly and actually enjoy the car.

The fact you are 19 is NO barrier or excuse, you are on a huge learning curve, and if you do it correctly the enjoyment wil be "priceless". My daughter and son both had a PreHE XJ12 as their first cars at 18, and did the maintenence themselves, under sufferance, and with my supervision, but the knowledge gained, made her XJ40, and his S3 XJ6, more enjoyable cars some 3 years later.

 

yeah i setup that post weird. I know thats a balance hose, it broke because I have taken it off alot already for the washers and again for the sending unit.

what do you mean geniune? you mean like nos from a dealer? I usually get URO stuff and its all been great so far.

I am aware there are alot of things that SHOULD be replaced because they are towards the end of their life cycle and i would love to, but i don't have the money to just go out and buy new everything for my car. New hoses alone are around 200 dollars.
the small lines on top of the radiator will be checked because im replacing my fan and they will have to come off anyways.
what happens to thermostats when they break? do they get stuck open or closed?

yeah i agree i love learning stuff and it makes owning the car alot more enjoyable....and you end up with more money in your pocket. rebuilding the rear brakes was a rewarding job for me but a pita at the time.

 

You're getting great advice from Grant, and I'm thoroughly enjoying following it.

Grant, if I could email some merlot it would be on the way.

The thermostats will likely be stuck closed so switch them out.

If the heater hose was burst I'd try fixing that, changing out or taking out the thermostats and try to run the engine and see what happens before you start pulling heads off, as everyone has advised that is going to be a major pain best avoided if possible.

Additionally once the heads are removed the road back to running will become expensive if you cover everything that should be done during the process.

 

not to be lazy but where are they? are they after that hard line towards the front of the engine on each side?
ex. drivers side near the power steering pump?

ill find em haha

 

I'm back, got sick of the Rover P3 restoration, AGAIN.

The meaning of "genuine" is Aussie talk for Jaguar parts, either dealer, if you are desperate, or an independent Jaguar parts mob, as long as they are Jaguar spec all is sweet. My main **** thing for "genuine" hoses etc is that it is a MONGREL job, and the last bugga up you want is one that dont fit, or rubs on something due to the angle of the dangle being slightly off. The botom radiator hose is a classic if its wrong, it rubs on the fan belt, DAMN. NEW hose clamps PLEASE, ALL round, never use old clamps unless its a patch job on the side of the road.

Thermostats usually fail SHUT, but anywhere is what I have found over the years, coz they are female by nature, think about it. You got 2, one on each side. Follow each upper radiator hose to where it joins the engine, FOUND THEM, congratulations hahaha. Now the serious stuff, the RH is 4 bolt attachment, well actually 3 bolts and 1 nut, and that nut is a bloody pain, so remove the 3 bolts first, then loosen that nut until it sort of jams on the spout, then release the spout from the engine, whack it, CAREFULLY, and slide it out a bit and undo that nut some more, until it comes off, remove that cover and the thermostat.

The LH is 3 bolts, and some feeling will be required to get to the bottom one, 1/2" socket and a short extention does fine.

Just to humour me haha, measure the length of the thermostats when closed, drop them in some boiling water and wait for them to open FULLY, it may take a few minutes, and measure them again, QUICKLY, coz they start to close quicker than they open. You are looking for 42mm OPEN LENGTH. Now my reason for that is simple. The distance in the housing where they sit, from the mounting flange to the by-pass port (down inside) is 41mm, and if that port is NOT CLOSED when they get near to open that engine will run HOT forever. During my time at Jaguar the "genuine" stat was WRONG, it was too short, and only opened 38mm, and we had a spate of hot running V12's, NICE, NOT. My 3 were some of them. I went hunting and found a replacement stat from a Ford, that is 82c, and opens to 44mm, and is otherwise the same, and EVERY V12 I have worked on since about 1998, has had the short stats fitted, and by simply replacing them with these longer ones fixes the "H" running forever. The Dayco part number for them is DT18A. The 2 gaskets for those housings are "genuine Jaguar" only, as they are a special material, requiring NO glue.

I hear what you say about $$. The heater hoses at the back of the engine are a forgotten item, and you will possibly find yours are original 1988, so at least do those 3, and a tap. Again with that tap, NO genuine, tooooooo much money. Go to NAPA (I think that is what you call them), and get a 5/8" universal vac heater tap, GMH, FORD, for about $20, and enjoy.

I have no idea where in the USA you are, but I use XK Unlimited in San Louis Obispo, for some bits, and find their prices reasonable. Others in your area will hopefully give some more chaoices of suppliers.

I will keep reading as i sip the necta, and write some more if I feel it needed.

The fact your engine is running "fine" as you said, and as I said before, I would put head removal on the real back burner. That is going to stretch to a $3000 parts/machining bill easily, coz once you start you go on and on and on and on.

Fix those hoses, and stats, and run the beast, and listen for valve clatter, you will hear it, trust me if one of more has dropped.

I still maintain you are one LUCKY Jag owner at the moment, dont push your luck with a V12, it will bite back, haha.

 

of course ill respond to this more later but you seriously don't know how lucky i am to begin with on this car man.