1989 XJS. 67K miles.

This picture is taken under dash, LHD drive car, driver side.

Is that a heater core leak? Car hasn't been driven in years before I replaced all hoses and rodded out radiator. Flushed coolant and added coolant flush with water. Multiple flushes and drains after this. It isn't wet after above repairs but cooling system hasn't been fully pressurized yet.

1. Thoughts?
2. Any chance that's from backed up condensation from A/C condensation tube?
3.How hard to replace heater core?
4. Is question #2 the result of denial stemming from the difficulty of question #4?

 

If its dry after all that work, I would suspect it is condensation drain tubes are blocked, which is common.

No idea on a LHD car, but the RHD is a mongrel, and the core comes out on the LH sidee, so you got more issues with access than we have, good luck.

Being an '89, it should?? have the "Update" Delanair a/c unit, with the "Manual Mode" on the temp switch. If so, the coolant pipes attach to the core with a clamp bracket and are sealed with o/rings, which do leak regularly. Easy enough to replace on RHD, but LHD might be fun.

If NO manual switch, then the coolant pipes are part of the core, bugga.

 

If it is leaking from where the pipes join the heater use later XJ40 o'rings, these fit and are an updated part.

You'll need to remove those vacuum solenoids and check them, they control vents etc and with the rust may need to be replaced. Pull ALL of the connectors apart and clean them with a switch cleaning solvent, you may even need to replace some of the connectors. I feel your pain I was there a few years ago with a leaking core.

 

Forgot to mention have a look at the way I went about it

Jaguar XJS Restoration : XJS Delanair Mk3 Repair

 

Holy moly! That was an in-depth repair. Looks like I'm pulling the dash-I JUST installed it after installing a dash cap.

Thanks for those tips.

 

Back a decade or more, I detected an odd odor and a deposit on windshield of my 85 Ford F150 4x4. Noted when the HVAC was in defrost mode. Glycol, that is what it was. I removed the heater matrix. Way easier than in a Jaguar!!!!!


I was tempted to solder it up. I filled it with water. Nope, no chance. many streams, some in the fined area. Twas not a smart idea. Sixty bucks for anew one!!!


Hardest part was cutting off the hardened hoses. Tight access for tools.


I modified the system in my 83 XJ wuzza 6. I added a manual valve in the hose not controlled by the vacuum operated valve. With both off, no hot coolant in the matrix. Run the fans for power ventilation in moderate weather!


Point:


Place the unit in defrost mode. run fan full on. Any odor and/or sticky deposit on the inside of the windscreeen. If yes, there is a leak!!!


Carl

 

I've done a couple. Not all that bad on a LHD car...and certainly easier than with the Delanair Mk II

In a nutshell...

Drain coolant.

Remove underdash trim panels, console cheek panels, instrument cluster, and glove box. Removing the steering wheel...5 minutes work.... gives more maneuvering room in general but isn't actually required.

On LH side of the case remove the close-out pieces where the pipes enter the case. Disconnect heater pipes from heater core. Have a towel ready.

On the RH side of the case there's a 2" x 5" (approx.) plastic 'door' that needs to be removed. Four screws, I think. I recall having to remove the grand-piano-shaped ECU first.

The heater core now slides out, to the right, via the opening created by removing the 'door'

it's been years so I'm sure I've forgotten a couple minor things but the above covers the basics of the job

Cheers
DD

 

Excellent! My interior is already disassembled so this may turn out to be an easy job.

 

New heater core purchased off eBay-replaced. Easy as Doug said.

No leaks, problem solved.

 

Good for another 30 years

 

I am wondering about this unit being called Delanair Mk3. I thought the Mk3 was later as in 1993-1996. I would like to know before I have this kind of trouble.
Thanks, RagJag

 

The XJS got the Delanair Mk III system in 1986-87. I can't remember exactly when....there's surely a known VIN break.... but my XJS, build date February 1987, had the Mk III system.

The Series III sedans with a V12 got the Mk III system in August 1986 so I suspect about the same for the XJS.

Cheers
DD