heat/ ac
 

Hey guys. I have a slight problem with my climate control. I brought it into a shop and the mechanic said id need a new core and theres a bunch of problems. As far as I know, the fuses are reaplced and blowers are working. I am getting air flow through the car. The water hose to and from the heater valve is hot when the defrost is on and the car is warm. The outlet hose coming out of the firewall, next to the hose connected to the water valve also gets hot. This leaves me to think that it is not the core. I do not get A/c either.

What should I do? this is a 1986 Jaguar XJ6

RE: heat/ ac
 

which "core" is the mechanic wanting to replace?

the EVAPORATOR inside the car?

or the CONDENSER in front of the radiator?

Are you saying you do not have HEAT ? In the middle of Summer?

If you are talking about the "core" in the center of the car's interior, I seriously doubt
that's the problem. Those never go bad. And if you did have to replace it, it would be an enormous disassembly of the entire interior. I could understand if it was the Condenser, but I also doubt it.

If you don't have a/c, make sure that:

1) the compressor is good,
2) there is refrigerant in the system,
3) replace the Heater Valve if you haven't already,
4) replace the A/C Expansion Valve if repalcing any a/c component.

More information would be good, you don't say exactly what the system is doing or not doing.

Jose

RE: heat/ ac
 

I do not have heat, but the winter is cold where I live, so I would like to try and have heat when I need it.

The mechanic was talking about the heater core. I dont have heat at all and without heat in this car during the winter it would be useless. No A/c in the summer is ok, just rolling down the windows. I would like to fix the heat, but i have checked the symptoms i have been issued to test thus far. Hot hoses to and from core, good valve, fuses.

The AC is still has the R12 system. I just wanted to know te next thing to check for the heat. No A/C is ok for now, but I dont know how to test it.

Thanks for the quick response.

RE: heat/ ac
 

OK, been registered for a whole 24 hours. I am going to "assume" that this is a Series 3 car????, and not one of the very first XJ40 style. If it is S3 I have dealt with thisbefore, although an Australian car, RHD, and downunder. If it is the XJ40 style dont read any further. the system is different.

The fact you have hot water at each side of the core is GOOD. The heater system is a complex beast at best, and if you do NOT understand its correct operating function, FIDDLING with it will "stuff it up" as we say. There is inside the unit itself a number of flaps that are continually moving to "blend" the air between the various chambers to give you heat/warm/cold, as per your request with the temp knob on the LH side of the control facia. Now as you have discovered, that in the "defrost" mode (RH knob), this overrides ALL othercommands, and supplies FULL heat and FULL fan to the defrost vents, this is normal, and a good sign that the system is sort of working. The flaps etc are all controlled by vacuum valves and levers etc on the outside of the unit, some on the LH side, some on the RH side, and the adjustment of these to give correct operation is critical and complex.

My best guess is that the "blend " flap is jammed. This happens coz the foam padding glued on in factory way back then, falls off and jams the flap/s. Sometimes just operating it from the outside will free it up, but I have never been so lucky.

There is a very lengthy procedure (too long for here), to testing this system. PM me if you want my way of testing it.

At the risk of being "banned" so soon, life goes on hahaha, there is an EXCELLANT write up, very comprehensive, in a book called "Experience in a book, help for the XJ-S owner", written by Kirby Palm. It is FREE and downloadable from Jaglovers web site. I looked here but cannot see a link mmmm. Although it is aimed at the XJ-S, this system, and many others things are the same as your car. It is well worth the read, and will clear up a lot of your questions. I used it 12 years ago to adjust my '85 XJ-S system that the previous owner had "fiddled"with, NEVER touched it again.

RE: heat/ ac
 

http://www.jag-lovers.com/books/xj-s/14-Aircon.html

RE: heat/ ac
 

You guys are pretty darn quick. It is in fact a series 3, so all your help, Great Francis, was worth while.

You are exactly right with these flaps, because all the flaps are always open for defrost. Just now, and it wasnt doing this yesterday, the air is only blowing out of defrost no matter what setting. I dont mind that for now, as heat is my first priority, and the air conditioning can wait a little while. I still only get lukewarm/car temp blowing through defrost when set to 85.

RE: heat/ ac
 

OK, good start. After you have digested "The Book", and are confused mmmmmm. the fact you have "warm" air is a reasonable start. The reasons for that are many and varied, BUT, without going to the inside unit yet, check that the heater tap is openeing FULLY, they are a well known problem. The operating lever in the "down" position is ON, the lever in the "up" position is OFF, and the taps default to full on with NO vacuum, so pull that small hose off the tap and make sure the lever goes all the way down. Next ensure that the hoses are connected correctly, just for the hell of it, the hose from the tap goes to the BOTTOM of the heater core, and the return coolant to the engine comes from the TOP spigot.

I am going to assume again, that the engine has a thermostat, and is getting to the correct temperature, and that there is GOOD coolant flow from the engine to the heater, I have seen many (my cars) with that hose outlet at the rear of the engine, on the RH side,blocked with crud, so the heater sees very little flow, and of course little heat mmmmm.

If it was my car,I would remove the 2 hoses at the firewall, and put the garden hose on the top spigot, and carefully, give the heater core a flush, in the reverse of normal flow, then repeat with the hose the other way, coz those cores fill up with "mud" due to sitting during summer.

The rest of the checks are involving the inside unit, some being simple, some not.

Keep us updated.

RE: heat/ ac
 

Alright, I am going to work on testing the amplifier and servo, if those reveal no heat I will definitely try your flushing method. Your method sounds a lot more fun than testing my amplifier.

It has an inspection appointment tomorrow, so lets hope it passes that. Ill have to put all this stuff back together for the time being.