Is this an AC port?

[GHEN]

Hi all,

On the attached picture, I believe I am showing the AC port which can be used to charge the system. Now I realize I won't be doing this myself (R12), but here are my questions:

A) Is this in fact an AC line?

B) Under that orange cap is a needle valve. When I depress that needle absolutely nothing happens. I assume this means my AC system is completely de-pressurized (it does not work). Is this assumption correct? Does this point toward a leak?

Note: I haven't yet had the opportunity to follow JohnAZ's excellent advice for troubleshooting the AC system, I am just trying to wrap my head around some things before I proceed.

TIA,

GHEN

[John_AZ]

Yes, it looks like a repair or an aftermarket line.

Note: Replace the schroeder valves in the 2 line(s) They are one of the many causes of lost freon.

Now you should check the low pressure switch as I mentioned (compressor still connected to 12V on frame). Jump the 2 wires you pull off the switch while the engine is running and the AC cabin switch on full blast. Only for a couple of seconds.

If completely empty, why not do the R134a retrofit?

GL
John

[johnkoawood]

Originally Posted by John_AZ

Yes, it looks like a repair or an aftermarket line.

Note: Replace the schroeder valves in the 2 line(s) They are one of the many causes of lost freon.

Now you should check the low pressure switch as I mentioned (compressor still connected to 12V on frame). Jump the 2 wires you pull off the switch while the engine is running and the AC cabin switch on full blast. Only for a couple of seconds.

If completely empty, why not do the R134a retrofit?

GL
John

I could be wrong, but the picture appears to show a R-134 adapter on the high pressure port.. meaning it was already converted?

[v2rocket_aka944]

that is an r134 cap and fitting. the r12 fitting is small and threaded the r134 is a clip-on sorta thing.

if nothing comes out when you push the schrader valve then the system is empty. r134 will leak naturally out of the old hoses over time.

[John_AZ]

GHEN,

Both are correct. I missed it. Your post(s) had mentioned R12.

Retrofit red/blue caps will snap on the retrofit stems that screw over the old R12 stems.



If the compressor clutch works after the low pressure switch test, the next step is to buy a set of AC hoses and dual guage at Harbor Freight.

With the guages you will be able it fill with R134a 1/2 can or so and watch/look for leaks.
Walmart+R134a about $10 a can, get 3 or more. (to be discontinued)

Does the compressor have an oil leak on the front coil/pully leaking down the compressor?

If you cannot see or hear a leak, you might just try to complete the refill.

A vacuum would be better but some have been lucky just to add up to 2 cans of freon and a litttle compressor oil/freon mix. Maybe a freon/oil and leak sealer detector can ???

You can always go back and vacuum and do it correctly if it does not work. Its only money.

GL
John

[alfadoc]

That is the high side service port, on a factory line, 1987-up cars. The low side service port is on the compressor. There is both a high side and a low side port on the compressor. The low side is closest to the driver's side, pointing straight down.

[John_AZ]

Thanks,
My '87 & '88 924S have the high pressure port next to the receiver/dryer.

GHEN
My freon "low pressure switch" is marked in the picture. Photo by dw215.

I am not sure where yours is. Maybe alfadoc can help.



GL
John

[johnkoawood]

Originally Posted by John_AZ

Thanks,
My '87 & '88 924S have the high pressure port next to the receiver/dryer.

GHEN
My freon "low pressure switch" is marked in the picture. Photo by dw215.

I am not sure where yours is. Maybe alfadoc can help.



GL
John

Interesting, my 87 951, and 88 N/A both have the identical low pressure switch, but high side port on the fender (in OPs pic) and low pressure side as described next to the compressors pointing straight down.. in fact every 944 I have worked on has these ports in these locations.. only other car I have seen with a high pressure port where yours is, is a 91 968 (had to remove the bin from the front of the airbox to get to the high pressure port!).

neat seeing the variations on each of the different models!

[HondaDustR]

It's already been retrofitted to R-134a if it has that cap.

If you're lucky, it's just a combination of bad schrader cores and hose leakage, but you might as well replace all of the o-rings while it's still empty. Jump the low pressure switch to see if the compressor does work. You may be able to save some money and just charge it, but there's a good chance you'll be spending more money to fix the underlying problem anyway, plus more refrigerant at $9 a 12 oz can. You really need to vac it down and replace the drier (like $12 here on pelican), since non-condensables like air will hurt system performance, and moisture makes acids, which destroy things. Heck, might as well flush it out, as there's no telling what kind of crap is in the system and how the retrofit was done.

[djnolan]

Regarding vacuuming a system, I hooked up the vacuum pump to the S last weekend as I wanted to charge the AC. After vacuuming for 20 minutes I closed off the valves on the gauges, shut off the pump, and watched the pressure. After a few minutes it began to gradually climb, and after 10-15 minutes it had climbed from -0.8 to -0.7 kg/hg. Anyone have an idea as to the type or severity of the leak this points to?

[alfadoc]

Originally Posted by johnkoawood

Interesting, my 87 951, and 88 N/A both have the identical low pressure switch, but high side port on the fender (in OPs pic) and low pressure side as described next to the compressors pointing straight down.. in fact every 944 I have worked on has these ports in these locations.. only other car I have seen with a high pressure port where yours is, is a 91 968 (had to remove the bin from the front of the airbox to get to the high pressure port!).

neat seeing the variations on each of the different models!

If you look in the factory service manual and the factory parts drawings, they show for 85.5 up as low side by the fender, and high side by the dryer. However, there is a notation in the FSM that the configuration is changed for 87-up, to high side by the fender, low side on the compressor. The low pressure switch is in basically the same location on both.

Some of you may remember me posting a while back that I couldn't get my A/C to charge correctly. Among other problems, I wasn't looking at the lines, rather I was taking the drawings for gospel. Skinny lines are high side, fat lines are low side. I had been trying to charge my car through the high side. Doh!

[John_AZ]

Originally Posted by djnolan

Regarding vacuuming a system, I hooked up the vacuum pump to the S last weekend as I wanted to charge the AC. After vacuuming for 20 minutes I closed off the valves on the gauges, shut off the pump, and watched the pressure. After a few minutes it began to gradually climb, and after 10-15 minutes it had climbed from -0.8 to -0.7 kg/hg. Anyone have an idea as to the type or severity of the leak this points to?

Put a spot of spit on the high & low ports first to see if a bubble appears. If you ever open the system completely put in new valve stems in both the Hi and Low ports.
Get a bicycle valve stem tool and tighten the valve stems if OK. You may have to file it open a bit but it should work. There is a special valve tool for either R12 or R134a valve stems.

Look at the compressor front shaft area by the coil/clutch. This is the No 1 area for a leak. Look for an oil deposit on the compressor. If you see an oil deposit a clutch reseal is necessary

Look at all the hose connections you can get to and check for an oil deposit. If the seals are deteriorated, a leak will show. You may have to pull the front plastic grill to see the condenser hoses.

Check anything on the High side of the system.

The smaller leaks and anything under the dash requires an electronic sniffer.

I picked one up on ebay and had to replace the batteries and get a charger for about $70 used.



Try another vacuum after you tighten the schroeder valves in the High & Low ports.

GL
John

[djnolan]

It is not the shrader valves as before vacuuming I had just installed a retrofit kit and tightened the shraders as suggested. That sort of leaves it at the shaft seal? There is definatly some oil on the compressor body. I guess I will order the compressor kit!

[John_AZ]

Originally Posted by djnolan

It is not the shrader valves as before vacuuming I had just installed a retrofit kit and tightened the shraders as suggested. That sort of leaves it at the shaft seal? There is definatly some oil on the compressor body. I guess I will order the compressor kit!

Have you rebuilt a compressor before?

John