I'm not getting any hot air out of the heater... looking for some direction.... i have checked the water hoses going in and out of the water valve and they both are warm the return hose on the firewall from the heater core never gets warm... it seems that either a valve (besides the water valve on the firewall) is not opening or the heater core is plugged up.. if you have warm water going in you should have it coming out....

Thanks
Todd

 

If you have hot water on both sides of the valve, the heater core is the only thing you have left. I would pull the return hose of and make sure this is the case. Pulling that heater core is an absolute bear. I would also replace the evaporator and expansion valve while you are there.

 

yeah...... i'm going to take the return hose from the heater core off and start it up and see if i get any flow out of it... if i dont i'll try to back wash the heater core by taking the water hose to the return side and see if i cant blow any thing out of the supply.... always something i guess

T

 

heater core isnt pugged up... besides the thermostat, water valve and heater core what else controls the heat?

 

I doubt it is the heater matrix stopped-up, it just doesn't happen in these cars.

it is most likely the heater valve.

The cheapest way is to go to Autozone and buy the following heater valve as shown in the picture below for around $9.95. Replace it and test the heater.





[IMG]local://upfiles/1235/486EC8D38F3F4547A4F691D34EA147E2.jpg[/IMG]

 

That's a good idea, Jose. He's correct, the heater cores will leak but uncommon to plug.

 

onceyou test the heater system with a cheap plastic heater valve, thenyou can order the better, original valve from Ken.

Have you replaced the thermostat too? Careful when removing the nuts from the thermostat housing, the studs will break. Treat the studs with Rust Buster for a few days before trying to remove the nuts. With the thermostat, do not use cheap substitutes. Use the Jaguar part.

 

I have heat.... most of the time. I replaced the water valve on the firewall and i now get heat out of the heater, one problem still lurking in the system. while driving i have the temp switch on 85, high as it will go, and the other one set to either fan high or low. Everthing will be working just fine then out of nowhere i get cold air out of the center dash vent and no heat. i have been switching it to defrost and it will blow hot again. seems to only do this when i'm running the floor vents and not the defrost.

any ideas
Todd

 

good, you done your homework.

now you need tosubstitute the Climate System Amplifier, that's the most likely culprit now.

Go to John's Cars http://www.johnscars.com and get their phone number. Call them and ask them for their substitute A/C Amplifier for the Series 3 XJ-6.

You don't even have to remove the old one, all you do is remove the left side Vent Panel (the one next to your right knee), and look for a large, rounded, cream-coloredPlug with many wires, (about 12 thin wires in different colors). (be very gentle with those wires).

Separate the two plug halves and install the new cigar-shaped amplifier to the proper half of the plug. I bet this will resolve the changing of temperatures from hot to cold.

BUT:
the Center Vent is normally closed during HEATER operation in these cars. It only opens ocassionally to dehumidify the heated air by cycling the A/C on and off. So even in winter, the a/c compressor will be turned ON by the system automatically. I bet you didn't know that?

However, if the center ventSTAYS OPEN during Heater operation, the amplifier is usually the problem.

The cigar-shaped "amplifier" (not to be confused with an Audio amplifier), is an aftermarket part developed in Australia for these cars. It appears to be more lasting than the factory part. It is also less expensive. In the USA, only John's Cars sells it as far as I know.

 

the illustration below shows the original factory Amplifier for the Climate Systemused in the Series 3 XJ-6with the Delanair 2 system, from 1980½ to 1987.

[IMG]local://upfiles/1235/75DD3453974F40CBBE73ABC68A5CF58E.jpg[/IMG]

 

As Jose said, its probably the AC amplifier. Mine acted exactly the same. Not sure what Johns cars sells the replacement amp for, but, if its more than $124.00, then go to Caufield Jags website. They advertise it for 190 Austrailian dollars, which converts to the $124.00 price. Shipping time was 3 days for me, and, about 8 bucks to ship, I think. I've seen this same amp as high as $280.00, depending on who's advertising it. Very simple to install, and, is actually better than the original.

 

that's a good tip Keith. Can you post a link to Caulfield"s? I went to their website but I could not find a link for parts.

thanks

Jose

 

I cant believe the words I am reading! I have a 1982 XJ6 with heater challanges. To say the least. Very cold car. I found it on ebay in Tucson AZ. Collector owned, clean reliable transportstion the listing promised. Well it really is a beautifull car. Silver, clean and shiny, chromed Kent original wheels. Brand new tires, Brand new pads and rotors in the rear, 12 disk changer, new seats, and perfect headliner. It looks like a bently or some other hand built motor coach. I love it. But the heater don't work at all. They never need heat in Tucson, but the AC is AWESOME! So I took it to a local guy here in po-dunk Montana and he recommends a heater core! OK it's cold, lets do it. Then he took apart the insides of the car and made the car heat only and none on the floor! The only heat I ever feel is if i leave the car on low fan. If I hit the high or auto or windscreen defrost it stays hot for 1-2 seconds, then gets progressivly colder. Very annoying here when it is 35 below! So, what does my car need?

 

A couple things:

This is a tricky system. There are a few easy checks that often work. If they don't, well, things can get difficult.

Make sure the heater valve is opening, and staying open when heat is called for.Its on the firewall almost dead center in back of the cylinder head. With the engine running have a helper operate the temp control from hot to cold and you watch to see if the heater valve responds. It has a lever-arm type actuator so you can tell easily enough. If no movement try disconnecting the vacuum hose....that should open the valve for sure.

With the system set to "auto" operate the temperature control. Do you hear a whirring noise? You should.

Post back

Cheers
DD

 

as you found out, the Heater Core or Matrix was not the problem!

it's either the Heater Valve as Doug says, or the Amplifier. But it could be a number of other components too, such as the Resistor mounted on the upper left side of the matrix case, it could be the Ranco thermostat, located on the back of the right side of the matrix case, or the little thermostat mounted on the copper pipe also located on the left upper side of the matrix case. it could be the TEMP Selector rotary switch. And of course it could be the Servo.

But all those components rarely go bad, it's the Water Valve or the Amplifier that are the most common problem. I always roll my eyes when someone says you need a new CORE! As you can see it did not fixthe problem but it sure kept someone busy charging you for all the hours worked.

In HEAT mode, (TEMP switch set to over 75 degrees), air only comes out through the two side dash vents, through the two center console vents, and through the rear seat vent. The large CENTER VENT opens ocassionally to dehumidify the air,but it is closed99% of the time, so don't expect a gust of hot air to come out through the top center vent ever, it doesn't work like that.

Also make sure the side-to-side LEVER under the Radio is placed in the center position. Set it and forget it.

The best way to check the Heater Valve is to substitute it. Ifa new Heater Valve doesn't do it,substitute the Amplifier. that's why I recommend you buy the AutoZone Heater Valve, it is cheap and easy to replace, you don't even have to remove the old one, just disconnect the hoses from the old one and connect to the new one, same for the vacuum line, though you might need a reducer from 1/4" vacuum hose to 3/32" vacuum hose. Still cheaper than buying the OEM valve.

 

http://www.caulfieldjag.com.au/home.htm, here ya go Jose. Once there, close to the top you'll see a list, look for "Products", click on that and another list will appear, "Maintenance", click there and you'll see AC Amplifier listed. Doug, Jose, you guys are great, lots of good info. The climate control system can be a nightmare for new Jaguar owners. When mine was acting up, I was ready to rip the whole system out and replace it with an aftermarket system like they use in custom hotrods. Thanks to whom I consider an expert on another site, taking me under his wing, guided me through the process, discovered, after the AC Amp, my problem was the very inexpensive compressor fuses under the console. (2 of them). Now it works like new. One more thing that is often overlooked, and replacing the heater valve will take care of the problem. Sometimes the inside of the valve will rust, either in the open or closed position. So, you may get what appears to be an operating valve, watching the vacuum arm move, when, in fact, it may not be operating anything at all. Cheers, and Merry Christmas to everyone. A little early, but going out of town soon and won't be back until afterwards.

 

Doug,

With the system set to "auto" operate the temperature control. Do you hear a whirring noise? You should.

Post back
I poped the hood and looked at the heater valve,and I just replaced this very part within the last 2 months. In fact I could not remove the old one entirely from the firewall, so some of it remains there.... Any way I assume mine is good since it is brand new. the vacum line is disconnected intentionally, my mechanic un did it and said to leave it like that. I am sure the factory would have a different suggestion. I sure would like to get it working properly. I have already spent 850 for time and labor on the heater core and still I have no heat. It is rigged to do nothing to my feet and mostly out of the center dash vent. I know, that vent isnt the main heating vent but in my XJ6 it is!

 

No vacuum = open heater valve.

Still need to know if you hear a whirring noise when you adjust the temperature control. That's "step one". The whirring noise indicates that the system is "alive" and trying to respond.

Cheers
DD

 

In my 1965 S type, the Heater Valve is of the NORMALLY CLOSED type. In other words, when Vacuum is applied to the valve, the valve is opened and coolant then flows to the core-matrix, providing heat to the interior of the car.

I may be wrong, but I think the XJ-6 valve is NORMALLY OPEN, (the opposite), so that when vacuum is applied, the valve is closed. I learned this by trying to install an XJ-6 heater valve in my S type at one point, but was told by several mechanics that I would need a REVERSED XJ-6 heater valve, i.e.,NORMALLY CLOSED. (such heater valve does exist in Europe).

Regardless of whether I am wrong and Doug is correct, the fact that the vacuum hose has been disconnected from the Heater Valve, tells me the system has been riggedor *******izedand thereforethe Heater MODE is not working, whether by the proper FLAPS not opening, (evidenced by the Center Vent opening when it should be closed). or by the heater valve not doing its job correctly.

I would connect the vacuumhose to the heater valve and start the diagnosis from there. Let's just hope that the mechanic did not *******ize any other vacuum connections elsewhere.

TIP: to remove or replace the original Heater Valve bolts and nuts, the grille under the Wipers must be lifted and removed. This is a delicate operation because chances are the two PINS holding the grille in place could break, so the trick is to use very thin but very strong STRING, sliding it under the grille then pulling the grille UP at each side, little by little. Doubled FLOSSING STRINGworks very well for this, it is strong enough to pull UP without snapping.If the pin breaks off, or is already broken off, therepair entails drilling a tiny hole in the center of the grille stub and the broken pin, (a DREMMEL TOOL IS NEEDED), thenepoxing a thin nail(or a needle cut to length) from whichyou have cut the flat head off, to both sections. That's how I repaired mine.

Even though this climate system can be scary at first, it is not that difficult to repair, IF you have the FACTORY SERVICE MANUAL to help with diagnosis. Molst of the components last forever, only a few ever go bad.

TRY THIS:

turn the engine ON, drive the car around for 15 minutesuntil the engine has reached normal temperature,

THEN turn the system to AUTO, TEMP knob at75, wait 3 minutes and turn the TEMP knob to 85,(max), and SELECTOR knob to LOW, listening....

then answerthe question made by Doug about listening for the whirring souind from the SERVO, (located on the front center of the console, passenger side), the SERVO makes a clockwork sound, like a mechanical Music Box movement (see picture below), lots of clicks as it moves.

 

Now that's clever !

Cheers
DD