22R88

My 1988 has factory A/C. It was converted to 134A after a front end collision years ago. With the 134A the system works well as long as you are moving but gets warmer at idle but it has been fine for the little use I put on the truck. I also have a small leak somewhere that I have to give a shot of 134 bout once a year but the other day while driving and accelerating hard the A/C seemed to let go as the temp climbed coming from the vents. I do not see any oil or anything to make me think the compressor leaked out but ??? Checking the system it seemed a bit low so I added a bit more but the strange thing is now at idle it seems to cool better(40 degree air) and while running it seemed to warm up (55-65 degree). Before I rip it all out and try to rebuild it does anyone have any clue as to what specifically may have failed ? If it is a simple fix I may patch it but I also kinda like the idea of trying to overhaul the entire system and fix it right.....Is there a way to make the 134A perform( different condenser or something ) right in these older systems ?
Is the 95 model Condenser a larger capacity than the one for a 88 ? If so will it fit in place of mine ?
I am currently flooded and out of my home but when I get my shop back I want to try and fix it and just doing research to have the best outcome.
I do have access to a set of gauges and a vac pump for when I start to fix it.

Thanks,
22R88

old87yota

I hope you don't have too bad of flood damage!

I have heard that R134A conversions don't cool as well with the factory setup when you are idling because there is not enough heat transfer between the condenser and the surrounding air (less air flow when stopped). This could be due to a number of factors. Some Toyota truck retrofits turn out great! Could be problems caused by the retrofit.

Does your radiator have a fan shroud? How about the lower piece that is often missing? These do make a big difference in cooling performance.

Did the refrigerant that you put in have leak dye in it? If it did, I would try to use a black light or whatever makes the dye easily visible to see where the leak is coming from. The leak can come from anywhere with the age of this A/C system.
Is there any collision damage to any of the lines or condenser that were not replaced?

I will be installing a factory A/C system next spring/summer into my truck without A/C so I don't have any "hands on" experience with messing with A/C systems yet.

As far as replacing the condenser with a larger one I don't know what fits but it could improve performance.

I would at least do these steps:

1. Find the leak
2. Get the system evacuated by a professional
3. Replace the leaking part
4. Replace the receiver/Dryer unit
5. Replace the "O" rings with R134A compatible ones
6. Inspect and/or replace the flexible hoses
7. Pull a vacuum on the system to check for leaks
8. Fill with the correct amount of R134A using manifold gauge set
9. Verify the high and low side pressures look good ( I still don't know what pressures are good, Time to do some research)

If you have time, I would see if there is debris in front of the evaporator in the dash. Leaves like to go into the fan and get stuck at the evaporator.

I don't know if this is helpful but here you go:




It is difficult to tell what is going on when there is a leak in the system so I can't give any specific areas to look.

Good luck!

22R88

Thank you for taking the time to respond. i do have the stock fan shroud as well as the bottom air dam. I do intend to find the leak if the refrigerant is low and replace all the usual parts. My main question is that the newer trucks 94-95 that had factory AC used 134A and they worked fine. While I assume a condenser from one of those will physically fit i wonder if it has a larger capacity or if my conversion was just not done right and mine never worked well at idle because of it ?? If the condenser is the same in mine and a 95 then I would be leaning towards buying all new stuff (comp, cond, evap,, exp valve, drier and flushing all lines then getting some R12 and charging it after verifying no leaks.....all that if the problem I have cannot be easily fixed back to it's status of a few weeks ago where it worked well except idling.
and I did get 8" of water in my home and currently live in a travel trailer in my backyard while the home is being repaired so Yota is on back burner but never far from my mind !!

Thanks again,
22R

scope103

Here's everything I know about air conditioning: https://www.yotatech.com/forums/f116...-r134a-284801/

Let me repeat old87yota's point #2 - get your system professionally evacuated. There is no home-shop way to do that, and letting R134a out into the atmosphere isn't just killing polar bears, it's killing all of us.

I don't doubt that a system designed for R134a from the ground up has slightly different components (larger condensor?), but I can tell you that a simply converted R12-R134a system gets plenty cold.

You'll note that Eric the Car Guy, who is not shy about tackling problems on older vehicles, advises leaving a/c to professionals. I ignored that advice and so can you, but just be sure you know what you're taking on. Finally, don't do things half-way. Adding a shot of 134 bout once a year means you're leaking out a can of R134a every year.

old87yota

After all of the research about A/C I have done here, I have never come across your thread. I am definitely going to read through it.

I think the main reason Eric the Car Guy does not recommend A/C work for the DIY is because people do things half way thinking that it will cure all of their A/C problems and in the process they often make things worse. If you pay attention to the details, replace what needs to be replaced and CORRECTLY charge the system, you should have cold air for years to come.

Through my research, I have found that R134a retrofits on Toyota trucks work just fine and blow nice and cold when people paid attention to the details (with the stock system).

I think that most people do a half baked retrofit and then complain that R134a is terrible rather than putting in the effort to do a proper conversion.


I think if you inspect / clean / replace all parts as needed, put in the correct oil type and amount, and charge the system with the correct amount of R134a, you should be golden.

I hope you get your house fixed up soon! I have never experienced a flood before. That must suck.

22R88

Thanks for all replies. I went get the Yota from storage and the A/C worked like it has the last few years. I think the system may be overcharged cause the pressures are like 50-325 but it is coold as hell moving and cool enough idling so I am gonna leave it as is till next spring I guess and if it requires total rebuild I will go that route then.

22R88

scope103

It may be worse than that. If you watch TV, "all you need to do" is buy the bottle with the built-in gauge and you're on your way in no time.

But charging an AC system with just one gauge (even if it was a good one) and no temperature measurements is a wild-ass guess at best. More importantly, that refrigerant got out for a reason; just pouring more in every few months is doing more harm than good. I had to get the gauge set and the evacuation pump (along with the o-rings, PAG, can-tap, and cans of R134a), so doing it close to correctly requires some investment.

There are plenty of folks on this forum willing to undertake that sort of preparation; sometimes just to learn something new. (Which is why I posted my blow-by-blow.) But I think Eric knows that his audience isn't quite at that level.