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Ford 6P148a options

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    Ford 6P148a options

    Last year I completely rebuilt the A/C system on my '85 Ford. Everything is new except the evaporator (flushed), and the Denso 6P148a compressor was a reman because new ones are no longer available. Shortly after I got the system all charged up, I discovered the compressor was leaking oil, so I stopped using it. Now I'm going to replace the leaking compressor, and I have a few questions.

    First, I can either go with another reman compressor, or for very little extra I found a new old stock Ford compressor. I'm wary of going with another reman, but I'm not sure I'd trust a 30 year old unused compressor any more. What would you go with?

    Next, what refrigerant should I go with? Last year I found some old stock cans of R12, so I had the system charged with that and used ester oil. I did this because R12 tends to cool better on these old cars, but obviously serviceability is an issue - the shop that charged it last time no longer deals with R12! I installed a parallel flow condenser and it has a stout electric fan set up, so airflow across the condenser should be good, meaning going with R134 probably won't be much less cool. Going with R12 would be much easier since I'd just need to top off the oil then vacuum and charge it (I wouldn't replace the drier), but I'm afraid of being in the same position I was a year ago. What would you do?

    Thanks in advance!

    Welcome LTDScott: Let's see what we can put together for this. First need to know if this is the small LTD guessing by username and the model year. If so that was really mostly a "Fairmont" unit body intended to replace the full size Ford cars which didn't work out so those would be called Crown Victorias folks wanted more.

    What happened was loaded with toys cars to help sell them still didn't work so that car line didn't last long as that name but similar to others.

    I can see now the problem is using R-12 now with ester oil is not compatible! This car new would list mineral oil or a paraffin which you could switch/retrofit to 134a with Ester oil would be compatible with some remaining mineral oil if it was the only problem with a failed compressor likely not.

    You can flush out the whole system and suggest you use 134a just get the fittings know that high side is a different thread size than low side port so need that one to be right.

    The condenser may be original and your call to use it which is much less efficient but tons more durable than the high efficiency one to replace it. If leaking you may not have a choice.

    IDK and would be hard to look up as Ford products were using names for cars at random for a while.

    It's your car so your call but I would retrofit this and leave good components along. At the age you shouldn't need to change out hoses for "barrier hoses" for 134a as they are so saturated with oil over so many years they'll likely stay sealed up just anyway if not a problem now even this old.

    Why 134a now? You'll run out of R-12 not made new since 1993 so any left is recovered and I question the quality of it or if faked! There's just plan more available for 134a but at best expect a 20-25% loss of cooling power but still has A/C and dehumidifies air inside is better than nothing for most folks with just putting on a very strong new fan clutch and get it flushed and new orifice tube which is no doubt clogged up and might be part of a hose and very hard to find and some do NOT come out rather part of the hose!

    Can't know as they put whatever they felt like in some of these and think it was the last model year of those if exactly what I recall.

    Re: used compressor? Used may be a lot newer and good but you won't be sure till installed. Problem here: The clutch may be unavailable as it was rubber vulcanized to metal to absorb shocks of turning on and off and the glue or what they used frequently failed up to plain fall off!

    Refresh: Are we talking about the car I'm thinking of? Need to know that. The Mercury version was identical called a Marquis not a "Grand Marquis" night and day different vehicles totally.

    Forget help from Ford and the aftermarket mostly gave up on this vehicle is just a real problem.

    Let me know just what you have but expect you may wish to just defeat having A/C at all and save the endless troubles and lack of parts and support for this car was fine but just the wrong car new to sell well.

    For me when these were 1/2 this age not a single person fought on with fixing A/C on these rather did without because of the hassles even that long ago!

    Nothing I know of totally wrong with the car as a whole except the model was just abandoned. Also Taurus model came out right then too took over like wildfire,


    MetroWest, Boston


      My experience is that a 30 year old compressor, sitting in a box may or may not hold up. I have had some that when pull out of the box were stuck, un sticking them they worked for awhile but the damage was done. Just like an engine, piston and rings can stick in the bore, bearing can dry out and get gummed up.
      If you replaced the condenser, And I always used the largest capacity parallel flow I can fit, that 134a does every bit as well as R12 with the smaller, less efficient condenser. The slightly less capacity of 134a over R12 is compensated by increasing the capacity of the condenser and getting as much heat out of the 134a as possible.
      My experience is with Tx valve systems and not orifice tube, but should help on them as well.
      It seams rebuilds can be hit or miss in terms of lasting. If you plan on keeping this system, it might be worth getting the tools and doing shaft seal replacement yourself. They can be tricky, and count on screwing at least one up, but the parts aren't that much, and with 134a you can charge yourself.



        BTW several things I have read, say ester oil is compatible with R12, PAG oil is not. The question is if the oil is soluble in the refrigerant and will be carried back to the compressor or not. PAG will not in R12 Since you are thinking of using 134a ester or pag is needed.


          Some things I can't prove or know for sure. "Mineral" oil was THE oil. I don't think 134a will move it but unsure if Ester could work with either or just can be added if switched does work.

          Totally agree NOS (new old stock) parts still boxed many would be totally no good. Seals would be failed unless they were purposely turned with oil on a schedule which doesn't happen,

          Need to know what this car really is the name alone isn't helping.

          Way to know - the LTD was a unit body car, rear wheel drive. Need to know that much. Most would be a 3.8 V6 engine possible if the Ford a 2.3 but doubt that. Mercury versions would all be 3.8s TMK.

          What can be from other or newer cars I can't know. The one I'm thinking of ended this model year! Again Taurus/Sable/Windstar were same platform all front wheel drive shared the engine in basics just put in sideways/transversely doubt brackets or hoses were close at all,

          MetroWest, Boston


            From what I read, All mfg when using 134a spec PAG oil, mineral was used with R12, and Ester was favored for the retro-fit market due to its ability mix with mineral. It also stated that ester will work with R12 but is more expensive than mineral, so if running R12 most kept with mineral. Ester was considered more or less universal oil in automotive A/C market.
            One the A-6's I run, I chose 150 PAG, but did use Ester in the 2 cyl recips, and it did ok.


              It's written all over the place and I don't have hands on proof. I'd love to see or mix the two in a glass system and really see it work but doesn't exist.

              Word was that "butane" used in lighters, some gas candles and camping things was a way to get both oils to move?

              OMG the labeling of product especially the high volume retrofit years was full of totally wrong info in print on what we called "Death Kits" once or just a box full of proper products and all the fittings many failed for just the fittings needed to adjust Schrader valve or a steady leak right way.

              Back some even if this is kept R-12 if an ample supply go for it but the parts were trouble 20 years ago to a couple on me. Used was tried for just the clutch I spoke of and all failed soon but worked for a while. It couldn't tolerate heat or oil and like a harmonic balancer just gave out, belt fell off or one kept engaged but didn't turn compressor!

              Not sure how many used those on what but couldn't find those new separately. Whole new compressor was then still available and very costly for what it was IMO to just get the clutch if nothing else was wrong at all should have been a quick fix and be done with it and was just didn't last with identical problem,

              MetroWest, Boston


                Sorry to get a little off topic, But A-6's are known for a small clutch and rubber damper on the clutch failing, the thing that seams to do them in is high head pressure when the clutch kicks in. The key to long life is to keep the high side as low as possible by not under size the condenser.


                  Wow, I wasn't expecting so many responses already! Let me clear a few things up.

                  Yes, this is a midsize '85 Ford LTD with a 5.0. Everything under the hood has been swapped with '93 Mustang Cobra bits, including most of the A/C parts (the compressor is actually the same on both cars, but some of the hoses are routed differently since the Mustang is EFI).

                  About a year ago I replaced nearly the whole A/C system: reman compressor, all new hoses (including the one with the orifice in it), new drier, and a new PARALLEL FLOW condenser, and a strong electric fan setup that is triggered by the pressure switch on the drier. The only original part left is the evaporator which seems to be fine and I thoroughly flushed it. I filled it to spec with ester oil on the recommendation of the shop who serviced/charged it, since ester is compatible with R12 or R134, and using Ester would mean that in theory if I ever wanted to convert to R134 later on (like I am now), I won't need to flush it. Everything I've read seems to say that ester will work with both. It's not the best choice - for R12 only stick with mineral, for R134 only stick with PAG, but ester is a compromise. I didn't use reclaimed R12 - I easily found new old stock cans of it on Craigslist, and it's not that expensive. In a past life I was an auto tech for a few years so I actually have the ASE certification to buy R12.

                  The car just a weekend driver and I only used the A/C maybe 5 times before I discovered the compressor had a significant leak from the body (not the shaft seal - I confirmed with a UV blacklight leak detector and a lot of time spent laying under the car). The compressor oil would actually drip down the front engine accessory brackets and onto the ground. When I did use it, it was fine and there's no reason for me to believe there's any internal damage in the system. When I discovered the leak, I stopped using the system, and a couple of weeks ago I had the remaining R12 charge (only about half of the original charge) evacuated so I could start working on it again, and that's where I am now.

                  I am not considering a used compressor - I found a new old stock unit on eBay for only about $30 more than a reman: http://r.ebay.com/hFSang
                  Yes, I'd have to swap the clutch but that's not difficult. I'm only considering this because I didn't have good luck with the reman I got and I'm wary to try one again.

                  I hope this gives a better picture of what's going on.
                  Last edited by LTDScott; 06-03-2017, 01:48 PM.


                    I understood you were considering NOS compressor, and I comment to that, My experience has been expect problems, hope for the best! Anything that sat for 30 years may have problems.
                    Your experience is not uncommon, If you can find a gasket kit, might be worth hanging onto to your old reman in case the NOS dies. If you can solve the leak issue, you have a back-up.


                      ? So essentially this is a 93 Mustang almost nothing to do with an LTD so can almost forget that. All 93 Mustangs are listed as OE with R-12 but charts can be wrong. List 40 ounces if OE now you have a new condenser not tube and fin would reduce charge by about 10 ounces! The box they came in used to say that inside but there's so much confusion with the two different gasses. R-12 take up more space than 134a and parts have been speced for 134a for a long time now. In short with wrong engine in this car and a new condenser you really don't know the amount of a proper charge and winging it is a challenge if either was newer. Factor all reasons you could get improper performance to diagnose first is high failure rate of remanufactured compressors.

                      OK - Wish I knew this creation from the top. Bear with all of us, site is new from a 20 year history of same site just new totally even I'm still finding thing that need changing to make it easier to use for everyone.

                      Back to oil compatibility with which gas. Same as already said - the first suggestions were not well proven and can find info both ways which to me means we may not ever be sure.

                      I doubt manufactures would change an oil totally if one worked with both without a problem. Same deal, oil is only for the compressor. It doesn't move in either type thru the system unless charge is real close and can move that oil or maybe it just dumps to the lowest spot and stays there? I can't know that for absolute sure. Watch out for some web info it's full of bull. Really - some spot on some just hackery to plain wrong.

                      Google out Scotty Kilmer's cleaning cat converters with dish soap no need to buy new ones! He's famous and sometimes quite useful then one comes along like that.

                      Buyer/viewer/researcher beware.

                      Back to this project. You current compressor is leaking badly not just making a stain but all wrong? Why is now important. Is it the oil or was it run too long on a low charge or no good to begin with.

                      Questions: To me when a system can't oil itself when engaged for any reason they knock a little or a lot. Way too much oil if correct type performance is erratic usually up to it might choke or lock with oil - can't know for sure by me for you about this oil thing.

                      I don't like that where I am you can't save your R-12 any more as around where I am nobody services or deals with it anymore. It's still sold but haven't last associated shop gave me their stock of as did a parts outlet for lack of demand or contaminated recovered junk.

                      So, with this leak if it worked at all and blew cool air for you guess I have to waste that r-12 and dump oil out of that compressor and see what the debris is if anything. Guess you could remove high side hose and blow backwards and see what junk maybe come back out from the "O" tube.

                      IMO even most defective compressors would only leak vapor not oil like that suggests oil didn't work out or horribly rebuilt and may not know for sure so easily.

                      BTW - if debris that condenser is already full of junk you can't flush out the ports thru it are too small to clean out effectively,

                      MetroWest, Boston


                        The AC systems in the LTD and Mustang are almost identical. The cars are built on exactly the same platform, and the engine compartments and firewalls are exactly the same on both. The only difference is the hose routing since the Mustang has a larger EFI intake manifold. Other than that, every major part is the same - compressor, evaporator, condenser. The condenser I bought is advertised to fit both the LTD and Mustang. And all '93 Mustangs were absolutely R12 from the factory.

                        I'm not sure I understand your question about the current compressor. It is leaking from a seam in the body. At first I thought I had an engine oil leak and I pulled the front accessories off my engine several times to trace it. Then I bought a UV leak detector and was able to trace the leak to the compressor, and confirmed it's not a shaft leak. I even wrapped rags around the compressor as a "diaper" and the leak stopped.

                        While I first noticed it because it was leaking oil, the shop confirmed that half the R12 charge leaked out over a year's time (I had it evacuated 2 weeks ago so it's currently empty). When I did run the compressor, it sounded fine with no abnormal noises, and the performance was acceptable. I have no reason to believe there is any internal damage in the system. Total run time was probably less than 30 minutes before I stopped using it, since I didn't want to run it with inadequate oil and cause further damage.


                          Just for the record how long a compressor can stay engaged with ZERO lube will vary if so. I've personally witnessed total destruction in 30 seconds not minutes!

                          TMK - the upper manifold of the 5.0 for 1993 I think is just to even out flow of incoming air for the active lower manifold not much more. It did add HP to this age old Windsor block engine not interchangeable but dates back to the early 1960s! Tough as nails iron heads and block noted for decent low RPM torque and embarrassing total HP but was/is quite fuel efficient as a nice surprise.

                          Some earlier ones before that upper intake you almost had a choice of using A/C at all or if you wanted the vehicle to move almost had to shut off A/C and a WOT switch did just that for some larger/heavier models with the same engine,
                          MetroWest, Boston