I just disconnected the two evaporator fittings. Tomorrow, I will find and fit a suitable rubber hose around the evaporator copper pipe and the manifold gauge and launch the test. It will be interesting.
Today, I enjoyed riding the cat with the renovated centre console parts. 
Otto âŚ
Iâm betting the evaporator is going to pass with flying colors 
The trick is to make sure you have a really good seal between the gauges and the evaporator. If it holds a vacuum on the first test ⌠perfect. If it doesnât donât be discouraged and recheck the connection again.
Using the gauges is pretty simple but if the test fails make doubly sure you have it set up correctly.
You really shouldnât get much up and down play on the transmission mount. Grabbing the driveshaft where it leaves the transmission is the best place to do this.
Did your rough idle improve when you replaced the foam buffer ?
Dennis,
I am in the process of checking the evaporator. What do you think, should I leave the vacuum line open when the pump has pulled the vacuum on the evaporator and I have turned off the pump, or should I close the line by closing the spigot of the pump? 
The rough idle or more likely the shaking did not go away even if I had changed the foam buffer. The idling is good but for some reason I feel shaking in the cabin.
Otto âŚ
Once you pull a vacuum on the evaporator as indicated on the gauge turn off the valve on the manifold to isolate the pump from the manifold and then shut the pump down. If you shut down the pump but leave it in the system itâs possible the vacuum could leak out through the pump.
A rough idles can be tough to track down since it can be caused by mechanical, electrical, or fuel problems. First thing Iâd check is the internal condition of the engineâs piston rings and valves. A compression test will give you a pretty good idea of whatâs going on in there.
Dennis, ok, thanks for the clarification. The evaporator seems to hold vacuum overnight, since when I removed the rubber hose fitting I heard a hissing sound.
. So, it seems that the condenser leaks. I performed the condenser vacuum test several times.By the way, where does the other end of this vacuum pipe under the vacuum tank go?
Concerning the idle, I performed the cylinder compression check last week, and the readings were correct, 170 PSI, for each cylinder. One thing I have not checked is the spark plug gap. I have to check it with a feeler gauge. Overall, there seems to be debate on the âcorrectâ spark plug brand. Some people believe in Champion plugs while others abandom them. I have NGK plugs which look very good after 2000 miles.
My old style Champion plugs looked good after 100,000km, just a FYI
I believe that, Larry.
I just checked one of the plugs, and the gap was correct, 0.9 mm.
Maybe the cat just needs to roll her bones like my favourite Canadian trio Rush in their song.
https://m.youtube.com/watch?v=mmIynF-59YE
Otto âŚ
Why didnât you use the dial gauge on the manifold to determine if it was holding a vacuum ? Thatâs the whole idea of the test.
If you feel confident with the results of your test thatâs excellent news. The condenser is very easy to remove and not that expensive.
hose #5 goes to the intake manifold where the vacuum is created (#4 is a one way check valve)
#1 is the vacuum reservoir for the climate control system
hose #10 is where the climate control system draws itâs vacuum for the various actuators.
Dennis,
Once I had pulled vacuum on the evaporator as indicated on the gauge I turned off the valve on the manifold to isolate the pump from the manifold and then shut the pump down. I noticed that if I shut down the pump but left the valve open the vacuum leaked out through the pump, in other words, the reading on the gauge lowered from minus to zero. If I kept the system closed (valve closed) the reading on the gauge did not change, and when I removed the rubber hose fitting from the evaporator copper pipe I heard a notable hissing sound.
Thanks for the pictures concerning the vacuum lines of the vacuum tank. The first picture I had checked from the Jaguar Land Rover Classic Parts site (which I find very useful site), but the second picture was new to me.
Otto âŚ
Just so I didnât confuse you the vacuum routing diagram I posted is for a series III XJ6. But except for the way some of the hoses are routed through the bulkhead itâs exactly the same as our XJ40.
By the way, the low and high manifold pressure gauges alway read the pressure (or vacuum) of the line theyâre hooked up to. In other words it doesnât matter if the valves are screwed open or closed. So in your case as long as you were holding a steady vacuum on the gauge youâre in good shape. Really happy for you that the evaporator checked out good !
Of course it goes without saying that anytime you open up your A/C system to work on it, always ⌠always replace the receiver/drier.
Dennis,
I replaced the drier last August, and the system has been open only occasionally, not extended periods of time.
I ordered in a new condenser. I am also thinking of ordering a Delphi expansion valve. As you know, I received a Denso valve last autumn, but the thread size was incorrect. The original valve is Delphi.
Otto âŚ
I still strongly recommend replacing the receiver/drier once youâve repaired your A/C system and determined it is leak free and can hold a vacuum.
The purpose of the receiver/drier is to store excess refrigerant and oil that the system isnât using at the time ⌠thatâs the RECEIVER part*.
Also it holds a small amount of desiccant that traps and holds any moisture present in the system ⌠thatâs the DRIER part.
The trouble is the desiccant can only hold so much moisture and once itâs saturated it becomes useless. And remember that moisture is the arch enemy of the inside of your a/c system.
So in my humble opinion as inexpensive and easy to remove as it is (you already have to disconnect one side to replace your condenser) go ahead and put a fresh one in.
Dennis,
thanks for your description of the operation of the receiver/drier.
Do you know what this blue connector under the MAF is? It does not have a counterpart. Also, the big black connector above it does not have a counterpart. Perhaps these are related to the Evaporative Emission Control system.
Assuming you are converted or converting to R134 is the Delphi expansion valve a replacement of original R12 valve or is it for R134.Thanks
exMBman,
Yes, the Delphi TSP0585012 expansion valve is for R134.
Thanks, one more job needing to be done soon.
exMBman,
I am happy that I could give you useful information.
Personally, I have received lots of useful information and knowledge on this site which I am grateful for.
Yesterday, I connected a vacuum gauge to the intake manifold vacuum and got 17 inches of vacuum with a steady needle which is normal for a healthy engine according to Haynes manual. I also tried to test the fuel pressure regulator, but the test was not valid. Hence, I ordered in both a proper fuel pressure gauge with a T-fitting and a hand-held vacuum pump in order to make a valid operating pressure check. The hand-held vacuum pump can also be used to test the two purge valves of the charcoal canister.
My pressure gauge and vacuum gauge are so old I do not trust their readings anymore so will be looking for new ones soon.
Still curious to see if the Delphi R 134 exp valve mates up with no drama like the original R12 valve did or if mods are required.
The original CAC8169 expansion valve is made by Delphi (part number TSP0585012) as illustrated here. So, it should fit. Let us see.
https://www.ebay.com/itm/Jaguar-XJ-88-94-CAC8169-Air-Conditioning-Expansion-Valve-New-OEM-/184312097477
That listing shows R134 , 88 to 94, as original which makes no sense at all. Late 94 MY is when it changed to R134. That is what is confusing. My system is R12 and I want an exp valve that will bolt in and be correct for conversion to R134. From reading other posts , it appears the evap was changed also in late 94 so it may not have the same pipe connections. I also have zero faith in using parts pictures from Ebay or anyone else for that matter,
as reference for what the parts really look like.
I really am trying to avoid having more parts I canât use or return economically.
Thanks for your help.
