ac problem

[doctorx]

Ok... at first I thought my compressor was going out. But added charge of r12 equivalent. The compressor kicked in just fine although it squealed when it started up. However, it blows just barely cool air. What could be the cause? the expansion valve? drier? condensor? Open to any and all suggestions. I have a proper gauge set on order. But with my cheapo that came with the R12 kit (from Red something)... it was reading 46 on the low side. When I initially checked it, it was about 12 and didnt kick in until around 20ish.

[cory58]

Ok... at first I thought my compressor was going out. But added charge of r12 equivalent. The compressor kicked in just fine although it squealed when it started up. However, it blows just barely cool air. What could be the cause? the expansion valve? drier? condensor? Open to any and all suggestions. I have a proper gauge set on order. But with my cheapo that came with the R12 kit (from Red something)... it was reading 46 on the low side. When I initially checked it, it was about 12 and didnt kick in until around 20ish.

Please post readings from the real gauges. Will help with diagnosis.

[doctorx]

whelp... something is definitely wrong. low is 32 ... high is 32. The clutch is engaged and spinning.... but acts like it isnt connected to anything. Compressor? or expansion valve. I think i had it connected correctly. Low up by strut tower and hi under the fender lip on passenger side.

[doctorx]

ugh... ok... apparently the compressor is really toast. going to 134a conversion. new compressor, drier, pressure switch, condensor, and evap switch. What i cannot figure out, what is the recommended way to flush the lines?

[cory58]

You can get AC system flush in an aerosol can from the auto parts store, or you can buy a tool that hooks up to an air compressor. The lines should be easy to flush. Just remove them from the car and run fluid through them. Flushing the evaporator is more difficult. Hopefully someone who's done it will chime in.

[cory58]

Not sure if you've thought about the new compressor yet, but since you are planning to do a full conversion, you should consider upgrading to a modern compressor. Finally someone is making an adapter bracket again for the M20 engine. It will allow you to use a Sanden compressor (or Chinese Sanden copy). Search for L. C. Wylie on Facebook.

[Tzantushka]

ugh... ok... apparently the compressor is really toast. going to 134a conversion. new compressor, drier, pressure switch, condensor, and evap switch. What i cannot figure out, what is the recommended way to flush the lines?

The OCD way of doing this is removing all the components and using a dedicated A/C flush solution & kit (reverse flush).

For driveway wrenchers like me, I don't have that equipment, so used non-chlorinated brake cleaner as the alternative.
If you can remove the A/C lines it's better & reduces the risk of getting solvent everywhere.
Make sure you use lots of (dry) compressed air to blow the evaporator out.
You don't want to introduce lots of moisture in there - just creates more work for you when as you have to pull it out under vacuum.

For me, as I have a RHD car, removing the evaporator was problematic.
You'll see from my build thread I ended up removing the TX valve, used some lengths of clear tubes and flushed out the evaporator in the car.

[doctorx]

Not sure if you've thought about the new compressor yet, but since you are planning to do a full conversion, you should consider upgrading to a modern compressor. Finally someone is making an adapter bracket again for the M20 engine. It will allow you to use a Sanden compressor (or Chinese Sanden copy). Search for L. C. Wylie on Facebook.

I believe what i ordered was for r134a... it came in a kit with drier and switch for 134a. I hope i ordered the right one.

[doctorx]

ok.. yes i ordered a 134a compressor. it looks just like the one i have in now so hopefully will mate up just fine... but looks like i ordered wrong compressor hoses... mine is a 87 325i vert manufactured in 06/87. maybe the existing hose is ok? I read that prior hoses were not barier hoses. I plan on starting to pull it apart tomorrow and getting things flushed. Parts supposed to be here Wens. but pump not until monday... i can at least take my time and do it right. what is the opinion on the stock aux fan? mine seems to work just fine after i bypassed the resistor.

[doctorx]

update: i replaced the compressor, condensor, evap, expansion valve.and drier. Getting 45F idle and 40ish at 2k rpm. I had to keep the aux fan resistor bypassed though.

[cory58]

update: i replaced the compressor, condensor, evap, expansion valve.and drier. Getting 45F idle and 40ish at 2k rpm. I had to keep the aux fan resistor bypassed though.

That is sweet! I got the same results having my factory Seiko compressor rebuilt with 134a seals and upgrading to a parallel condenser. Enjoy the "cool" ride this summer.

Cory

[doctorx]

That is sweet! I got the same results having my factory Seiko compressor rebuilt with 134a seals and upgrading to a parallel condenser. Enjoy the "cool" ride this summer.

Cory

compressor failed... seals failed in it... *ugh* replacement will be here tomorrow.

[doctorx]

ok.. replacement is in and system is charged again. The last remaining problem is the condensation is leaking between the expansion valve cover and the main housing. The drains are working now. Before i go all redneck and spray flexseal over the joint, anyone have any suggestions? No visible cracks. But can watch it come out between where they mate up.

[Tzantushka]

ok.. replacement is in and system is charged again. The last remaining problem is the condensation is leaking between the expansion valve cover and the main housing. The drains are working now. Before i go all redneck and spray flexseal over the joint, anyone have any suggestions? No visible cracks. But can watch it come out between where they mate up.

Few options

1) you can buy a small diameter rubber o ring cord (best option & similar to OE)
2) butyl tape rolled into a thin strand to fit in the housing groove (but gets messy)
3) cut a small slither of self adhesive closed cell foam & staff that into the groove.

[doctorx]

interesting... whomeever was in there last, there wasnt a o ring cord... i got it to stop dripping with silicone adhesive. I had some left over from my vert top.