[85lebaront2]

Is there an upgraded condensor that will fit these older K bodies and their descendants? I am getting ready to put mine back together soon and have figured out a way to get a bigger cooling fan system for it. I have to go to a front of the condensor mount in order to get full coverage due to the turbo-II intercooler. I have a nice dual fan with two speeds and a control system (factory relay for low, additional relay operated by a pressure switch from a 1993 Caravan for high). I know the original condensor was so-so on R12, and damn near unusable with R134. I am hoping someone knows if the replacements are better than the originals.

 

[AllanC]

. . . . Is there an upgraded condensor that will fit these older K bodies and their descendants? . . . .

Typically replacement A C condensers for older vehicles that originally used R12 refrigerant are upgraded in aftermarket supply. If the OEM condenser was a serial tube and fin, the replacement is most likely a parallel flow or serpentine flow for greater heat transfer. Are you going to use the original condenser or is it damaged / leaking and needs to be replaced?

If the original condenser is not damaged and is known not to leak then I would suggest you convert the air conditioning system to R134a refrigerant and use the original condenser. Then monitor suction and discharge pressure when in use and engine idling. Some condensers designed for R12 will still provide adequate heat transfer with R134a refrigerant.

 

[85lebaront2]

Did that on the 1985, never could get the head pressure down at a stoplight due to the fan system on the turbo-II setup. Old condensor is an unknown quantity, considering everything else on this car, I wouldn't trust it anyway, 32 years old to begin with. My local A/C guy told me about the replacements when I pinged him this evening. I don't particularly want to do it twice and already have engineered a better fan system. Even with the multi-blade fan and a new motor it doesn't pull enough through since the radiator is Omni sized and the intercooler precludes using a wider fan or shroud. I have modified a Ford Contour fan to a pusher to go in front of the condensor, it is a dual 10" two speed assembly and definitely moves some air.

 

[AllanC]

A C condenser / heat exchanger is rated in rated in BTU / hr heat transfer. You would need to compare the specifications for the OEM condenser versus a modern replacement. It is probably impossible to find the design specifications as a lay person.

Your idea to supplement additional air flow with pusher fans is probably a good solution. Only concern I would add is the increased electrical load placed on the vehicle at idle with 2 additional electric fans running. Current draw might be in the range of 10 - 15 amps and might cause a discharged battery if you do a lot of city, slow speed driving. You might need to upgrade the amp output of the alternator.

 

[Bob Lincoln]

It's a myth that these condensers are no good for R134a. While the serpentine flow doesn't shed heat as well as parallel flow, they still do a good job with R134a. The trick is to REALLY pull a good vacuum. The Factory Service Manual calls out for a vacuum of 26 inches minimum. That's no good. You need to pull at least 29.5 inches of vacuum, which means running the pump for an hour after testing for leaks. Makes a huge difference in efficiency. I have vehicles which feel as cool with R134a as they did with R12.
The other problem with installing a replacement condenser with parallel flow is that most of them have the connector block mounted at a different angle from what your hoses allow, so you can't connect to it. Some of them have different orifice sizes.
Increasing the air flow is a much better alternative.

 

[85lebaront2]

Several items, I have been doing A/C work since before a license was needed to buy R12. Second, I already have the 90/140 Bosch alternator as I know these fans pull a fair amount. Third, I have an old Laboratory Welch Duo-seal vacuum pump, it will pull a 29+ inch vacuum with no problem, it is strong enough to pull a slightly leaking system to below 29" with no effort and I usually leave it running with the high vacuum bleed open to finalize the pull down for at least an hour. FWIW, I have a crew cab Ford I converted to R134 years ago, it will damn near grow icicles on you even on high 90s with humidity at the same level. The Ford required a multi-pass 1994 up condensor to get the required cooling efficiency. We are going to look at the catalog and detail drawings before ordering a new condensor.

 

[ImperialCrown]

There was TSB #24-01-95A which described the best (factory approved) procedure for refrigerant conversion as R-134a took over in 1993. Also see attachment hot links on page:
TSB 24-01-95 Rev. A (at http://dodgeram.info/tsb/1995/24-01-95.htm )
There have been numerous threads on Allpar about refrigerant conversion. See here:
1st Gen A/C covert to R134a (at https://www.allpar.com/forums/threads/1st-gen-a-c-covert-to-r134a.160696/ )
You may have to replace all rubber seals and use barrier hoses:
What is Barrier Hose? - Pelican Parts Technical BBS (at http://forums.pelicanparts.com/porsche-911-technical-forum/108518-what-barrier-hose.html )

 

[85lebaront2]

Imperial Crown, I already have a full set of the updated barrier hose, the switches I will be using for the fan and safety are actually the ones for the 1993 Caravan and since the car is apart at the moment getting the floor replaced (joy of owning a 32 year old convertible) all seals will be new along with the receiver-dryer and an R134a expansion valve (also for the 1993 Caravan). Since I had owned one, I knew what to look for as factory R134a parts. The hoses were obtained from LKQ when they decided to clear space in their Linthicum MD warehouse and made them available at a discount. Interesting on that TSB, it doesn't show the full text, I was able to scroll around a bit on the site and get the compressor drive belt PN, which from my previous experience on my 1985 was an issue, it would slip the belt unless it was way over tightened even then, with a big fan in front of the car, the belt would flutter like crazy on the drive side.

I do have a complete aftermarket conversion kit complete with the R134a conversion labels. I am hoping I can find an improved seal for the compressor discharge hose set and the suction hose set as the receiver-dryer joints were always a problem on these cars with the thin rubberized aluminum gaskets. I always called Chrysler's engineers a few choice words when adjusting the A/C belt tension, the beautiful alternator and even power steering belt adjustment on these engines, particularly the ones with the ZF pump are great, then the A/C belt tension adjustment is a "what were they thinking?" deal.

Thanks for those links I will update the project thread as it progresses (T2K-CAR rebirth).

 

[85lebaront2]

Update on this. After doing some parts list searching and comparisons, I found Chrysler made some major changes in the HVAC systems in 1992, condensor was changed from the serpentine to a multi-pass design (it has an inlet and outlet header and each of the individual U-tubes goes across and back) compressor was changed to a Denso unit, and the evaporator was also changed. My original idea of using the two switches was kind of torpedoed by lack of a way to tap them into the system, but I found my 1994 Taurus uses a binary switch to give the same functions so that was a solution.

Wednesday I went over to the shop where the floors are being done and then to his junkyard and removed the entire HVAC system from a 1992 Plymouth Sundance 4dr sedan with probably a 2.5L engine. This gave me a Denso compressor, the multi-pass condensor, all the plumbing and spare innards (for the most part) for the 1992 Imperial all electronic ATC system I will be using. The Denso compressor has the high pressure cutout in the manifold block so I will go back to using the 1993 Caravan high pressure fan switch as soon as I find a way to plumb it into the HVAC high pressure side. The plumbing, condensor and receiver-dryer match a 1992 J body which means they are the correct dimensions for a K body (I have verified this previously).