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1991 Horizon 200 cab ac blows hot


Nana Banana

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The parts are available, most of us have functioning A/C. It could just need a recharge, EBay has NOS R-12 cans. If your system was really abused then the cost can get high. You need to decide if its worth it.

A proper diagnostic is needed.  

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Are you mechanically inclined? Is your compressor running? Is the system charged? There's a checklist to start with with these kind of things but if you're not mechanically inclined AC repairs get expensive really fast. 

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Had great ac in our 1989 Odyssey until just this year.  I’m going to be looking for the obvious before I take it to someone to do an expensive leak check and recharge...because it went down after the long cold winter and seems kinda sudden.  I’m ‘about’ to look at the ac compressor belt and electrical connections.  We did call an ac shop who said they don’t work on 89 toyota trucks because they’re too old.  They also said it would need a conversion.  

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51 minutes ago, Alvin said:

Had great ac in our 1989 Odyssey until just this year.  I’m going to be looking for the obvious before I take it to someone to do an expensive leak check and recharge...because it went down after the long cold winter and seems kinda sudden.  I’m ‘about’ to look at the ac compressor belt and electrical connections.  We did call an ac shop who said they don’t work on 89 toyota trucks because they’re too old.  They also said it would need a conversion.  

It's probably already been converted, I haven't come across a Toy home that hasn't. You can usually tell because there will be a conversion adapter on the low pressure side of the ac system where you charge it. Start by turning your AC on high and seeing if the compressor is even running and the clutch is engaging (given the belt is still there). AC systems have a low pressure switch that will stop the compressor from turning on if the system is low on refrigerant to prevent the system from burning up if out of refrigerant. If the compressor isn't turning you can try adding some refrigerant to the system with a can of refrigerant and simple gauge from walmart or wherever else, auto parts stores usually overprice these btw. once the system reaches adequate pressure it should start turning the compressor. 

If you want to do a leak test yourself you can rent a set of gauges and a vacuum pump from an auto store usually for free. You can find YouTube videos that will explain how to use the gauges. Use caution with high pressure side and make sure you trust yourself before attempting this. The gauges will tell you if there is any refrigerant/ pressure in your system at all. If not, you can do a vacuum test to pull  a vacuum on the system and then let the system sit for a few hours and see if the system is still under vacuum, if not, you know you've got a leak (or multiple). 

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Thank you and what a great set of instructions to get me started.  As luck would have it, I inherited my Father’s set of gauges for recharging ac... i don’t know how to use them but will do the research.  

 

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It would be good to know just what the refrigerant is R12 and R134 don't play well with each other. Done properly the R134 fittings are different in a retrofit and the compressor oil is different also. It is bad JuJu to mix the stuff. Basically if it's empty and it has small fittings you have no idea what was in it. If it's empty a vac pump is essential. If the fittings are large then some one has been there it's safe to assume it's 134. 134 is charged with a ambident temp=pressure chart so the high side pressure will be different at 60* as opposed to 80*. As Anthony said if the pressure is low enough the compressor will not run being cheap I jumper the low pressure switch instead of wasting a can of refrigerant if it kicks on then proceed from there. Cars/trucks manufactured before 1994 had R12  refrigerant. 

 

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