R12 a/c
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Junior Member
Joined: Dec 2012
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R12 a/c
I have 91 f 150 with the 4.9 in it. I have been buying all new parts to rebuild the a/c. I was thinking about just flushing the condenser since the old ones have the larger tube and fins. Would the new style condensers preform the same as the old tube and fin?
I know I should just go 134a with all new parts, but I want ice cold ac. it gets to 109 here and every degree counts.
thank you
I know I should just go 134a with all new parts, but I want ice cold ac. it gets to 109 here and every degree counts.
thank you
Senior Member
Joined: Feb 2016
Posts: 118
Likes: 22
From: Louisiana
I just finished a R134 conversion on an '88 F250. The condenser on the 8th gen is a tube and fin or serpentine and the 9th gen 1994 is a piccolo condenser. So, I looked at a replacement condenser for the '88 which appeared the same as the original. The piccolo condenser will mount in the 8th gen, however, a little modification will have to be employed in the mounting ears. Also the fitting in the liquid line is a #6 on the 8th gen vs #8 on the 9th gen.
So, in other words, using the original R12 condenser would be fine. Even in our 100 degree weather the discharge pressure maintained 250-300 psi with the factory fan clutch.
If you decide to use ester oil in your conversion, it can mix with mineral oil in the system, however, you'll lose some efficiency. But if you use , then you'll need to flush out the whole system. I recommend flushing though.
You will also need to purchase a R134 cycling switch to use with your replacement accumulator. The system will hold approx. 7 ozs PAG oil total. I usually add 4 ozs PAG oil to compressor, 2 ozs to accumulator and 1 oz to condenser. And charge system to 80% of the original R12 total capacity.
Also, you might have some difficulty removing the orifice tube out the evaporator. A orifice tube puller works better than needle nose pliers great until it breaks the ears of the tube. I usually will spray a little penetrating oil on the orifice tube to loosen it up and sometimes employ a little heat as well with a butane torch. Even after all of that sometimes you'll have to use an extractor. Good luck with your conversion.
Senior Member
Joined: Dec 2011
Posts: 13,811
Likes: 3,184
From: Texas
I just finished a R134 conversion on an '88 F250. The condenser on the 8th gen is a tube and fin or serpentine and the 9th gen 1994 is a piccolo condenser. So, I looked at a replacement condenser for the '88 which appeared the same as the original. The piccolo condenser will mount in the 8th gen, however, a little modification will have to be employed in the mounting ears. Also the fitting in the liquid line is a #6 on the 8th gen vs #8 on the 9th gen.
So, in other words, using the original R12 condenser would be fine. Even in our 100 degree weather the discharge pressure maintained 250-300 psi with the factory fan clutch.
If you decide to use ester oil in your conversion, it can mix with mineral oil in the system, however, you'll lose some efficiency. But if you use PAG oil, then you'll need to flush out the whole system. I recommend flushing though.
You will also need to purchase a R134 cycling switch to use with your replacement accumulator. The system will hold approx. 7 ozs PAG oil total. I usually add 4 ozs PAG oil to compressor, 2 ozs to accumulator and 1 oz to condenser. And charge system to 80% of the original R12 total capacity.
Also, you might have some difficulty removing the orifice tube out the evaporator. A orifice tube puller works better than needle nose pliers great until it breaks the ears of the tube. I usually will spray a little penetrating oil on the orifice tube to loosen it up and sometimes employ a little heat as well with a butane torch. Even after all of that sometimes you'll have to use an extractor. Good luck with your conversion.
That's colder than my 13 Lariat, nice work!