So like so many others before me I am a proud new owner to a classic XJS. I bought the 62k mile Lucas non-running machine for a good deal, betting that I could resurrect it back into life. The car holds a special place in my heart as I was a car porter for a jaguar dealership when I was sixteen. I was able to drive them then and have always wanted one for my own. Those many years ago thecar seemed to be made out of unobtainium. This one fell in my lap. It was meant to be. Little did I know going into this that I would be reading more about the eccentricities of this car than I have read about anything else in the past ten years. Labor of love. I say.

Here is the issue:

Is it running hot or not?
I have read the dire warnings posted about overheating. I believe them all.

This cars temp gauge visits the below N range only for a few minutes afterstart up. After that, the gauge spends most of the time half way between N andH. Venturing closer to H if it the car sits still idling. I have double checked the temps in two ways.

First: Infrared temps sensor. Readings are...

RH and LH thermostat housings after being driven 170-180F

after sitting still (running)185-190f

LH coolant hose at radiator 184F

Valve covers 190-200F

Big Castle nut on head deep in the V between the two middle intakes. RH and LH sides 203-215F

Second: A neat radiator cap temp gauge that sits on the crossover pipe fill.

It reads 165F when driving and goes up to 190F at the moment the aux fankicks on while idling.

Are these normal temps? Am I going to drop a valve here? My thought is afaulty dash gauge. Any thought from those that have been down this path wouldbe greatly appreciated.

 

These don't sound that high at all. Mine sits around 195 once its warmed up.

Once the electric fan comes on does the temp drop again?

 

I agree that those temps sound OK. But that's no guarantee that your valve seats will stay in place! You have to make sure that you have complete coolant *flow* through the cylinder heads. If you don't have full flow it doesn't matter what the coolant temp is. Wherever the coolant isn't flowing is going to get very very hot.....while elsewhere in the system it might be a very comfortable temp.

Sounds like your temp gauge is reading a too high, though.

Cheers
DD

 

Sarc: Thank you for answering. The temp just kind of hangs out around 190F while idling. If I were to begin driving it goes down again.

Doug: Thank you too. Given the number of posts and dire warnings on the matter I fear what you are suggesting. I'm trying to decide on taking the car to get the coolant system flushed or to try it myself. I would much rather have somebody else do it but I'm afraid of them doing a bad job not being familiar with the V12.


I am seriously considering getting a duel electric fan set up.

 

Welcome to the XJS forum. Congrats on buying you dream car. I did just like you and it's great.
The car is not overheating. But as Doug said, coolant flow may be poor. Before doing anything further on the electric fan front, one question:
Have you removed the radiator and cleaned out the fins? And cleaned out the fins of the two smaller radiators in front of it (do not remove these do them in place, and inspected it for good condition?

IF not, do this first, as they get blocked with road debris, oil etc etc, and must be cleaned out every few years. This is a known XJS fault/maintenance issue. At the same time check that the engine driven fan clutch (the silver thing on the back of the fan blades) is working correctly. It should freewheel on a cold engine and tighten up to drive the fan on a hot one. If the big fan freewheels when you stop the car when it is hot, the clutch is shot. This is a very common fault.

While doing all this, replace the thermostats with 82° OEM ones, and the pressure caps. as Grant Francis says, these need replacing every few years, and, as you will learn, what grant says is the business.

Greg

Greg

 

That is good advice. I need to have a hard look at the inside and outside of the radiator. When I purchased the car it came with some shop receipts. Among the was a receipt for new radiator and reservoir tank. The date on the receipt was from 2007. I am confident the car sat most of the time since (insert disapproving look). This may not be good news. The reason I say that is when I was installing my new radiator thermocap thing. I noticed some black floating bits in the fluid and a rough inner service on the filler neck. This could just mean that during the radiator replacement they just reused the same crossover pipe and its going bad. My the sky is falling fear is that the complete cooling system oxidized during the time the car Sat( insert nervous eye twitch). As far as the fan clutch goes, I hadnt thought of that. In the past when I had one go bad(bmw 3 series) it made loud noise that made the car sound like it had a super charger. I will check the other two coolers for junk too.I notice some leaking liquid something coating the lower components around and beneath the radiator(insert another nervous eye twitch) I am still very much still figuring out what I'm working with this car. The cooling system seams like the best place to start.

 

bbish now.

My suggestion is to remove that NEW radiator, have it cleaned inside and out, then clean the a/c condensor, and the oil cooler below it, and address the "funny liquid" you mentioned in that area.

Remove ALL, and I mean ALL, the coolant hoses, and renew them complete with new clamps.

Remove the 2 thermostats at the same time, and with them out, flush teh engine internals as best you can. Replace the stats with teh correct length units with NEW Genuine stat gaskets.

Remove the LHF wheel, and the metal panel behind it, and remove the 5ltr Plastic bottle, and flush the mud out of it. Blow thru the hose that travels TO the LH metal header tank, as ut blocks up with gunk regularly.

Remove the metal header tank, and flush the mud out of it, then refit it.

Ensure the 2 small metal pipes traversing the radiator top support panel are CLEAN, and also the Banjo bolt on the RH top of the radiator.

2 new radiator caps.

1 NEW heater tap.

Replace that front cross pipe with a stainless unit at this time.

DO NOT forget to flush the heater core when the hoses are OFF, as that sucker stores some serious mud when the car is unused.

That should see the cooling system work just fine for a good few years into teh future, AND save that engine.

The FLOW that Doug mentioned is critical, so when you flush that block out, take your time, flush it BOTH ways, and then DO IT AGAIN. That engine is a mongrel for flushing without stripping it down, but at least you can reduce the guunk with a little effort.

 

Wow! That sounds like my winter project. Thank you for spelling out all the steps. I would of done probably thought of half of that. I did discover a new issue unfortunately. While warming the engine to check the fan clutch I noticed wisps of something coming from the windshield vents. It formed what looked like a condensation on the windshield. If memory serves me right I had a Ford escort that did this many years ago. I'm pretty sure it turned out to be the heater core. I really have no idea what is involved with fixing this. I suspect it's going to be a challenge. I will do some research on it.BTW the fan clutch is bad. It actually turned easier once the car warmed up. I'm going to attach some pictures of stuff we've discussed just as soon as I figure out how to do it.

 

please excuse the last post. forgot to proof it. my grammar isnt that bad

 

Grant has nailed it as per norm. I hope for your sake the heater core is ok because that is a TOTAL PIG to fix. Think rebuilding the heating system then double it. Also the #1 cause of heater core failure is worn engine mounts - check them or your will be locked in a cycle.

 

OH MY.

Tyran has understated that a tad.

From memory, HAHAHA, the core sort of comes out the LH side, BUT, you got the steering wheel on the wrong side of the car, and the steering column will be in the way.

Greg in France has done it recently I think, but his is a RHD car.

I suggest a pressure test of the cooling system, and see what that uncovers.

The S2 Sedans, same climate system, basically had the heater core installed, and then the car was built around it, get the picture.

 

Uhg! Sounds like it might be a bigger challenge that I initially thought. Well I walked into in to the purchase with my eyes open . Maybe not open enough but open non e the less. I expect you guys will be seeing a lot of me over the next few months. Thank you again everybody for all of the input.

 

Some pics:
Jaguar Forums - Jaguar Enthusiasts Forum - Even's Album: Even's 89 convertable jag

 

An '89 will have the Delanair Mk III Climate Control so the heater core replacement isn't all *that* bad. Still not a pleasure cruise to do, but much easier than on the earlier systems.

In a nutshell, from memory.....

1) remove instrument cluster

2) remove glove box, underdash panels, and console cheek panels as needed

3) remove pipes from heater core

4) slide heater core out of the case via the access opening on the RH side of the case


That's a bit over simplified as there are other small bits to remove along the way....but that's the basic idea. About 6 hours for a first-timer, I reckon.

Cheers
DD

 

THANKS Doug.

Now I know its an '89, and the Del 3, the pipes are attached via a clamp arrangement and sealed with o/rings that fail often.

Maybe thats all it is.

 

Challenges, yes, but a well sorted XJS is 100% worth the effort. A few thoughts:

1) It's useful to remember that repairs cannot be rushed on these cars. If you rush, the car will fight you. Work slowly and methodically....and the job will actually go faster. Trust me

2) Over the years very distinct patterns have emerged as to what sort of repairs these old XJSs typically require. Sad to say that many haven't been well kept so the new owner is stuck with quite a laundry list....and it's always the same old stuff! The mantra here is 'do it all, do it right, do it once'. The cooling system work is a good example. You can drive yourself crazy repairing the system one item at a time....or resign yourself to doing it all in one slug and getting it over and done with. There are other areas where the 'do it all' method makes a lot of sense. We'll get to those later

3) Remain philosophic. For example, don't become disgusted when you happen across Jaguar's foibles that result in more work and/or frustration. In fact, the best idea here is to simply change your mindset. To wit: Jaguars do not have design faults. Anything that *looks* like a design fault is actually "an interesting engineering feature". Remember that and you'll be whistling while you work!

Cheers
DD