A/C question on 86' XJ6

Thanks for the info!

If this "one-way valve" should fail, would this cause the heat control valve to not get the proper vacume to close in the cold setting?

I have checked the heater valve and it never moves from wide open. It seems to function ok if I move it manualy with the line removed (I can hear air moving in and out as I move the actuator).

Thanks

Dennis

There are a number of vacuum sources on the engine. The AC is fed through a line at the right rear firewall which incorporates a one way valve. This line enters the car via a steel connector on the side of the footwell projection. Inside the car it can be found by removing the right vent trim and pulling back the carpet. The smaller line is the feed out of the system to the heater valve. The valve has a vacuum feed when the cold is selected.

Jaguar affectionado and etc.

I found a lose vacume line in the engine compartment. Re-connected it and the venting now "attepmts" to change and it seems to do so at its own wishes. I found that a sharp slap on the dash directly above the top center vent eases the transfer of the dampers.

If I lift off the top of the dash will I be able to get at these dampers to make sure that they are not binding and can move freely?

Thanks

Dennis

I think that you may have hit on a major lead for me!!! When I turn the rotary dial from warm (arrow down) to cold (arrow up) located below the radio. No change in venting occurs. It stays on the lower and outer top vents.

I am thinking that there may be a loss of vacume connection at this dial. This is based upon the pictures provided to me by the prior owner. The shop that did the conversion had the dash of this Jag completly apart, even the steering wheel was OUT. Perhaps this line has worked its way lose.

Thanks

Dennis

Before getting into complicated testing first do the basics. On cold, the majority of the air should come out of the large centre vent. On hot, the centre vent closes and the air comes out of the footwell and side dash vents. Switch from hot to cold and see if the change occurs, if it doesn,t then the problem could be a loss of vacuum to the flap system, check the vacuum supply from the engine. Secondly with the AC off check the system pressure with a gauge, it should be over 60Lb. Then run the engine and with the AC switched on see if the compressor is working. This is a complicated system and I would suggest going to someone who has the tester to check where the fault lies

Jaguar affectionado and etc.

the a/c amp in my '84 looks like the photo below. But remember I only said 'it may be the a/c amp'. There is also a small inline Water Thermostat with two wires to it and it is also a source of your symptom.
I have a '97 Mercury Sable wagon with R134A and it cools great even at idling, I can see ice stactalites forming on the vents! (just kidding), but then that system was designed with R134A from scratch which
may make a difference. The XJ a/c amp is a GM component similar to the Ignition pack. The new a/c amp replacements look like a cylinder (like a small flashlight) and cost around $125.00. Yes, I have heard
that Freeze12 is as cold as R12, requiring no conversion or system flushing, uses the same system oil, in other words, compatible. My system has been charged with R12 since 1999, and it is still freezing in
there, (knock on wood!).

Oh I forgot one more point, J.A.M. talked about the poor cooling of R134 converted systems. I have not really experienced this with any systems I have converted. The only noticable difference is that sitting at a stop light the cooling is not quite as good as it was when the system was charged with R12 BUT the second you get the car moving again and air flow in increased over the condenser, the difference is not even noticable.

I have heard of the "Freeze12" that he mentioned and have heard that those who have used this product are pleased with the results but again, in my experience, I have completely satisfactory results with converting R12 systems to R134.

For instance, another JCNA member and I both have Series III XJ6's (see photos of them in the "gallery") AND we both own 1987 Buick Park Avenues as our daily drivers. My Series III was initially charged with R12 and when I had a compressor failure and converted it to R134 again, the only difference I barely noticed was the slightly less cooling at idle I mentioned earlier.

As far as our Park Avenues go, mine is still charged with R12 and her's is charged with R134 and there is essentially no noticable difference in performance EXCEPT for a barely noticable difference in the "sitting at a stop light" scenario I mentioned earlier.

Oh and by the way, the conversion was done three years ago so yes it may need a recharge since it has been three years. There may be a very small leak at one of the hose connections or where the expansion valve is fastened to the evaporator.

A good thing to do during the next recharge is to add flourescent dye that can bee seen with a black light in order to find any small leaks. You can buy R134 refrigerant with the dye in it.

The amplfier is accessed by removing the kick panel on the driver's side of the console. It's a square box with a large round, multi-pin connector. It is not easy to replace but it is not that hard either.

First though, I would check to see that the system is charged properly, does the compressor come on? About the climate control, you said "it comes on for a bit then blows hot air" does it blow cold first? If so, for how long?

There is an in-car ambient temperature sensor located right under the padded dash. The air intake for this is right above the glove compartment door. It can be accessed by removing the padded dash which is very easy, there are only four screws that fasten it to the dash.

I would recommend doing a bit more trouble shooting before spending the $300.00+ on an amplilfier. You also could have a faulty controler which is located in the console which can be accessed by removing the kick panel on the right side of the console.

Thanks for the tips!

Now what does this amp look like? Is it hard to get to? How do I find this bad boy?

Thanks

Dennis

Your question may be quick but there are no quick answers!! it may be the A/C Amplifier located near the Stereo, that's a symptom of a bad amplifier.
I would check by substituting it with a known good one. John's Cars in Houston sells a replacement/aftermarket amplifier for less. I also understand the
Australians have come up with a better amplifier. All car a/c systems lose some gas on a yearly basis. R134A is known to work poorly in these cars or
in any retrofit. I still use R-12, it is available but very expensive, but that's a luxury I won't do without. Another less expensive alternative is called Freeze12
which is a laboratory mix of 80% R134A and 20% R22, (R22 is used in residential a/c, it is a very cold refrigerant). Freeze 12 is EPA approved for use in
automotive a/c. (you can't charge a car's a/c with R22 only because it would freeze the system). Since your system is already compromised, you might
experiment with Freeze 12 if not happy with R134A. (not many people are anyway). In either case, let a Licensed Technician do the work, these refrigerants
can blind you for life. There are many other alternative refrigerants by different names, each one addressing R134A's lack of cooling power.