# 1990 D21 a/c problem



## JackF999 (Jun 5, 2008)

Guys..
I have a 1190 4cyl Hardbody that has been garaged for 
more than 5 years. It has 50000 miles on it.

A mechanic worked on it and it is now driving good.
Passed TX inspection with no problems.

A/C, however is another story.
Truck is worthless to me without A/C so please help???!!!

It blew cold a few times when I was testing. Didn't want to 
keep it on too long.
A few days later I decided to test it for a longer period of time.
When I came back after 30 minutes it was blowing warm.

Tried one more time but in the early morning. Started cold but
after 30 minutes warm again.

So...

Could be low pressure switch. (Low charge)
Air gap on the clutch.
Bad coil ect.........

Only thing is everything I know about a/c I'm reading
from e-books from autoacsystems.com.
I don't know anything about the particular a/c system on 
this D21 truck.
Could someone please answer a few questions, 
and offer some advice??

Would be everso grateful, Thanks


----------



## JackF999 (Jun 5, 2008)

*My questions*

So after that intro...
My questions:

Is there some site with better than average info
that would help me with the a/c on this truck?

After all this time sitting is it better just to buy a new
compressor, borrow a vacuum pump, replace the accumulator
ect.... flush and fill full retrofit? or with only 50000 miles
could I get 2 years with just topping off with something like
es12a??? 

Will this compressor really fit my truck??
eBay Motors: New Compressor 85-97 Nissan 720~D21~Pickup~Pathfinder (item 160166655182 end time Jul-04-08 15:45:45 PDT)

This post really is only to get the ball rolling.
I can guess that someone who understands the a/c
for this truck needs more info.
I have gauges coming and will be able to report pressures.

I'm going to give it the old whack the clutch test soon.

Does this truck have a low pressure switch I can jump?
Where and how do I do it??

Thanks so much, I appreciate all comments.


----------



## Rogue_Wulff (Nov 14, 2007)

Sitting 5 years, I'd bet the system is low on refrigerant. Likely the front compressor seal is dry, and allowed the R12 to escape. A recharge could fix it up, for a while. Be it 2 days, or 2 years, is anyone's guess.
If you are going to replace the compressor, might as well go all the way and retrofit for R134a. Anyone can currently buy cans of R134a, and it's not that exspensive. Probly be able to retrofit for about the same as just getting it recharged with R12.
I retrofitted my 1990 Kingcab a few years, but failed to get the old oil fully flushed. This later bit me in the butt, as the drier clogged up, and caused the condensor to suffer from an over pressure, resulting in failure. I was driving 70-75 MPH when the drier clogged, and it almost killed the engine before the pressure switch killed power to the clutch. I knew the drier was plugged, and failed to notice the A/C switch was "on" when I turned on the blower to defog the windshield late one night, after dropping into a valley.
Now I need a condenser, drier, and a vacuum/refill, assuming the comp didn't suffer damage. I stopped immediatly, and saw freon blowing thru the rad. Since the hot weather had pretty much ended, I just unplugged the clutch.
So, if you end up retrofitting, be sure it's done by a knowledgeable person.


----------

