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Weak Air Conditioning In 1991 Ls400


daffy

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Hi,

I noticed my air conditioning in my 1991 LS400 is weak now. I would like to recharge it, but not with R134A. I see there's a new refrigerant out called Autocool HC 12A. It's suppose to be completely compatible with R12 and R134A and more efficient. Anybody try this yet in a Ls400? Can I install this stuff myself? Thanks, Daffy :)

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Daffy,

I put it in my 90 and it worked fine for a year..till the compressor went out..though, in my opinion, not a fault of the 12A. When I replaced the compressor that's when I converted to 134. Great stuff IMHO..though some will disagree but I've been there. The compressor only failed because the high pressure hose underneath it fatigued. Hope this helps.

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I've owned multiple 29- 32 year old Toyotas with factory AC and their hoses are still leak free. So I don't believe R12 hoses will fatigue as long as the owner keeps using R12. All R12 substitutes spell trouble, one way or the other. If you live in Canada, R12 is totally illegal. So you might need to have a contact in the USA buy it for you on ebay and then you could drive down to the USA, recharge your system then drive back home to Canada

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I'm saying..use the r12 or r12a...The hose fatigued while using r12..sorry you misunderstood. No problems at all since conversion to 134a. We thought the compressor was leaking so I ordered a new one along with drier and condensor and decided it was a good time to convert so we replaced all of the o-rings. When we pulled the old compressor that's when we found the leaking hose which was leaking before using r12a which was used "because" of the leak. The leak got worse and worse and that's when I ordered the new compressor. 2 years now and no problems.

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I still don't believe the compressor hose was leaking. Those hoses are much too thick and tough to crack. I believe it was the O-ring that seals the hose to the compressor that was leaking. The usual cause of leaking O-rings is system non use during the winter months. In any case, Autocool / Duracool refrigerants are flammable hydrocarbon refrigerants that have been around for decades and no one hardly uses them except owners who have junker cars and just want to temporarily get the AC system working again or who want to get the AC system working so they can sell the car with a working system.

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Hi All

So I really don't have any choice, other than upgrade to accept the newer refrigerants? Seems no one has had any luck with any of the new refrigerants like Autocool HC 12A or Red Tec 12A on the older systems. Bummer :(

Daffy

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Daffy, Every summer its the same story. Monarch says R134 will destroy your system. I say just empty your system and fix the leaks. Replace the fitting on the low side, evacuate the system and charge with R134 with ester oil in the cans. You don't even have to replace the reciever dryer if you don't want to. I've been a mechanic for 30 years. I'm not talking about something I read in a manual. My system works great and all the systems I have retrofitted work great. Believe me the Lexus o-rings etc. arn't any more prone to R134 failure than any other cars. I will say this again this summer. Volvo told us to change all the o-rings at first back when R12 was banned and then a year later came back and told us it was not needed. They took the o-rings out of their retrofit kit. The ester oil makes the o-rings compatable. By the way if you get a leaking o-ring down the road guess what, it's an old o-ring that would have failed after 16 years with R12 anyway. Changing all the o-rings isn't a bad thing. I'm just not going to do it for fun.

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Daffy, here is a long established auto AC forum where you can spend hours reading posts about refrigerant conversions: http://tinyurl.com/jsju6 The forum consensus is that R12 systems should not be converted to R134a or you risk degraded system reliability, durability and performance. You will also find out that quite a few owners who switch to R134a want to switch back to R12.

As I mentioned before, one problem involved with converting to hydrocarbon refrigerants like Autocool HC 12A is flammabilty and here is an example of a fire that occurred due to an AC line rupture: http://ed.scherer.name/2004-928OC-IC/photo...l/index_13.html (although the risk of bodily injury due to an refrigerant leak fire is small)

If you don't want to visit the USA to get some R12, then you should convert to R134a following Toyota's official hardware conversion guidelines which are quite involved and costly, but help miminize the problem of reduced system reliablity and durability. There's a TSB that outlines the conversion process and is probably available as a .pdf from the clublexus.com website.

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Hi monarch,

So I could take this car down to the USA and have a shop recharge the airconditioning with r12 freon without any problems? Otherwise I have no contacts. Daffy

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