Greetings folks. I am remiss for not being on here much recently, but despite being a Jaguar enthusiast to the core, other things seem to steal the focus of my priorities!

My 1993 is driven minimally, especially in a Northeastern USA salt-corroding Winter, and my example is on a strict NO SALT diet to keep its pristine looks from its Arizona-based past life. When I got it, the battery was a year old, but needed to be replaced after the car was parked in the garage undriven for about a two week period. Before that, it had use about once a week.

The battery was replaced, and I have it on a trickle charger when not in use. I took it for a 100 mile run about two weeks ago during a break in the weather, and I noticed that the battery light came on, mostly all the time, after about 40 miles of steady highway driving around 65 / 70 MPH. I needed to do a quick pass, and accellerated quickly. The light did come up after parking the car on two different stops, and stayed on during my return journey home. I took the car for a spin this afternoon, and the light was on (occasionally going out, but it seems to go on with some brisk accelleration, quick cornering, that sort of thing.) I stopped at a car parts store to get the battery tested, and the guy told me it was at 100%. He admitted that electrics are not his area of automotive expertise, but suggested the alternator.

I haven't gotten around to hunting for shorts and replacing fuses, but may do that soon if time permits. My mechanics are phenomenal, and I plan to take it there for routrine service soon. Just wondering what my XJ40 brothers (and any sisters here?) might recommend regarding this situation, and how I might want to approach it. Honestly, I don't care if I need to replace the alternator as any repairs done just allows me to keep things in top condition. That being said, if it the alternator is not the issue, could I end up replacing it again due to some problem in the system causing a short?

Thanks to everyone in advance. Hope everyone is enjoying their cars!!!

 

First on my list would be check for correct tension on the belt. too loose and it will slip, causing low or no charge. Then check the connections on the alt itself. My hot wire is a bit finnicky and comes loose every so often when I try to brag on the car. All ground straps are a good third choice too. good luck!

 

When I worked at a shop in the 1980s, I had a customer with an XJS that came in with a complaint about the battery light coming on occasionally so I tested the alternator output. I told her that everything looked normal with the belts and wiring.

She came back a day later with the same complaint and demanded I replace the alternator.

Rebuilt/exchange unit installed, she paid and left.
Came back again with the same issue. The boss said to replace the unit AGAIN so I changed it and checked EVERYTHING with the charging system. (OK)

A few days later, same complaint. I asked if there was anyway she could be wrong about the problem.
She 'lit-into-me' about how the car was bought NEW by her and she knew every little idiosyncrasy about it.

I asked what BATTERY light was on when the problem occurred.

She pointed to the COOLANT LEVEL LIGHT.
I tried to be nice and told her that the light was the RADIATOR icon, not a battery icon.

She got in her car and drove away!!!!!!!!!!

I did not see her for a few weeks and the subject was NEVER discussed!!!!!!!!!!!!

The RADIATOR and BATTERY icons look similar so be sure you are looking at the correct one.

 

Hi Jerry, Thanks so much for some direction on this. I trust my shop, but it's helpful going in to know what I might expect. Still love the car as much as ever, and the anythign finnicky goes with the territory on these.

 

I will eat the entire humble pie here, motorman because, indeed, I mistook the battery icon for the radiator icon. In my defense, the radiator wasn't even a consideration as I had significant work done on the cooling system last year, with work including: Antifreeze/coolant flushed/changed; Thermostat housing/gasket replaced; Thermostat replaced; Water pump and drive belts replaced; Water pump gasket replaced; Water pump replaced. The battery checked out fine, but when I took it to the shop a couple of weeks ago for an oil change, they did say that the coolant was low, which I found a little alarming after all the work done (and expenditures associated with such). Yesterday, I got around to putting a clean cookie sheet under the car, fortunately in a different place by chance....near the firewall / behind the front axle rather than under the radiator area. I happened to check this afternoon, and was astonished by how much had accumulated there in 24 hours...approximately 8 inches in diameter. I am bringing it back in to this shop, which I do think is reputable, but it concerns me that after all that work, there is still this issue. If anyone has any suggestions as to what this issue may be and how to address it, those ideas would be most welcome. Thank you gentlemen (and any ladies here). Motorman, I've never been so glad to eat a whole humble piw because sometimes humility is worth a great deal more with the knowldge that comes with it rather than foolish pride!!!

 

Just relating experiences I've had in the past and your story reminded me of that incident.
Glad you got it figured.

 

Hah, no worries, motorcarman (I left out the 'car' previously, inadvertently)! It's a good story and a lesson learned, which is all that matters! Regardless, what might the cause of the current coolant leak after the work completed in August as mentioned in the earlier post? I haven't driven the car significantly. The location of a coolant leak at the firewall is possibly a hose? Anything else you could think of, and could it be an issue unrealted to the coolant leak last Summer?

 

The plate on the back of the cylinder head would be a difficult repair. (not much room)
Heater hose?

 

If the leak appears to originate from the driver's side, possibly worn heater valve. Mine leaked and had to be replaced - Could also be leaking water manifold -this is located under the intake manifold and connects to the water pump via the "*******" hose. When it leaks toward the rear the coolant will make it way down and drip toward the firewall, driver's side. I hope it isn't that, big job.

Larry

 

Just for clarification, this would be unrelated to the work done previously (Antifreeze/coolant flushed/changed; Thermostat housing/gasket replaced; Thermostat replaced; Water pump and drive belts replaced; Water pump gasket replaced; Water pump replaced.)?

 

Yes, unrelated, as you say. Altogether different areas for possible leaks. You should inspect these areas carefully before making any decisions.

Push a shop towel under the heater valve - if damp/wet after a drive, that could help diagnose/eliminate the valve as the culprit. Just an idea.

Larry

 

Motorcarman and Larry....your assessment was spot on. Thank you for preparing me for what I might expect.

 

Regarding replacing the hoses near the heater core, what other preventative work might be done at the same time, if any?

 

The valve is a common possible leak point, hoses a possibility but rare in my experience. If the leak is from the water rail gaskets, well, that's a whole different story. FIRST JOB - Find out where the leak originates from.

Larry

 

I had it at the shop and the tech believes it is hoses.