who knows 1Gen Dodge diesels and/or automotive A/C

bigwaylon

bigwaylon

Well-Known Member
Joined
Mar 22, 2005
Location
Charlotte
here's the deal...going to look at a used 1Gen ('89-'93) D350 tomorrow...


owner says A/C just "stopped working" a while back...but said it's obviously still the R-12, and the quote was for $1800 to fix it an convert it to R-134a...

now, I've had an old truck converted before, and the kits can be had for ~$50, so I'm thinking he's got a high bid from the dealer or something, and that maybe something is also broken...

that being said, it's worth it to convert it before I start working on it, as last I checked (a couple years ago), R-12 was ~$45/lb, and R-134a is just a couple bucks a lb...

I'm pretty sure I could fix it (or get it fixed) along with the retrofit, but I'd like a couple hints on what I should look for when I see it...

assuming if it "just stopped" working, there's a single part that's gone bad, or maybe a freon leak...I'm not sure if it actually blows air at all or not...

should I still be able to hear the compressor cycle on/off if it's good? and maybe it's the condensor, or just out of (or low) on freon?

I'm taking somebody with me that knows the 12V CTD, so the mechanical parts I'm not too worried about (and he may know A/C, but I was looking for a little advance info)...

Good thing is the truck has ~225K and the guy that owns it bought it with 13 miles on it...so he knows the history...

Greg
 
If the AC compressor and system doesn't have freon in it, it will not ingage the clutch to make it spin. IF it has no belt, it may be froze up due to lack of oil. Look for wet/oily spots around the hose fittings. I am not too up on CTD compressors but this stuff goes with about any of them.
Could also be a switch. You can jump a hot wire over to the compressor from the battery and see if it starts turning.
IF it's a bad compressor you can pick one up at a bone yard. usually $50 to $100 bucks. surely that compressor is on others and not exclusive to the CTD.
On the switch to 134 some compressors are easy, others you have to deal with exspansion valves driers and such, sorry I am no help there.
Hope some of this helps
 
upnover said:
On the switch to 134 some compressors are easy, others you have to deal with exspansion valves driers and such, sorry I am no help there.
Hope some of this helps
Click to expand...

Is there anyway to know beforehand?

All the kits I've seen never differentiate...they just say things like "convert without letting air into the system" and "contains additives to allow use of the mineral oil that's already in the system" and other things...

Thanks.
Greg
 
I know that when an AC guy does it, he pumps the system down, so the additives, and coolant does not add to the pressure to build up enough pressure to blow a hose.
 
also, when retrofitting an older system to use r-134 you must remember two things.

First use only 75-80% of the recomended charge. and second that the 134 runs a much higher head pressure so an old system is more likely to spawn new leaks.
One way to help combat this is to run an auxilliary electric fan to help cool down the condensor and this will help the system to function standing still as well.
 
good news...

bought the truck today...and went to check to see if any old freon was in it, and it was bone dry...

$36.98 at Advance, plus 20 minutes of our time, and the A/C is running great...:D

Greg
 
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