Hi RicoS,

Having a cool AC for 5 years then suddenly compressor lockup I think you're having a leak in the system somewhere. A slow leak causes low refrigerant condition which leads to reduced lubrication to compressor, compressor slow damage and finally lockup.


To answer your questions:

1) A general road map - you'll need to

a) check for remaining refrigerant
b) recover refrigerant
c) dismantle old compressor out of car
d) check system status - debris, sludge etc.
e) flush system clean
f) install new compressor
g) install new filter-drier
h) find leaks - nitrogen method or recharge refrigerant with UV dye
i) repair leaks
j) vacuum system
k) recharge system with proper refrigeration oil (amount/viscosity/type) for new compressor
l) have a cool AC again!


2) Can AC compressor be hydrostatically locked?

Technically it couldn't. The compressor has "reed valves" for each cylinder. The intake valves are just thin metal flaps which open easily to suck refrigerant in but the discharge valves are made of thick springy metal flaps which require stronger force to open. In short, easy to go in but harder to come out. This is HOW the refrigerant gas is "compressed".

Should a liquid refrigerant went in it would be easily sucked in at the intake valve and "spurted" out of the discharge valve. No hydro lockups here. But in doing so the discharge valves could get damaged/weakened plus the pistons encounter greater forces to work with during that high pumping-compressing speed. And this could be heard as unwanted "noises" or "grunting" at the compressor. Prolonged effect would be compressor damage.


3) Which compressor is the best buy?

Generally all AC compressor is good. Granted there are some more efficient than others. But due to unavoidable reasons such as local/internet availability, installation points (attachment to engine) and types of available installation ports, we are sometime stuck with limited choices.

Personally I would prefer a rotary compressor which has negligible load on the engine (such as Seiko-Seiki) but then itself is a rare item plus parts are hard to come by.

Second choice in terms of low engine load would be the Sanden. But please be aware of counterfeit Sandens especially those with hard to believe low prices.

Third choice would be the Zexel/Diesel Kiki/Seltec/Tama. This last choice appears to be widely available plus parts aplenty. You'll have to use refrigeration oil with anti-wear additive in order to get the best out of this.

Regards,
Amarin.

hello rico,
i added a comment to machineman's referenced link.

it's on sanden compressors.

i don't know about the 93 240s since they are rare and i've never worked on one.

judging, and only judging by FCPgroton's photo, it looks like my purchased sanden may fit your car, but please do your due diligence before deciding.

this compressor does not come with a fitting, but uses interchangeable fittings. please read the link for the fitting part number i used.

regards,
byron golden
86 245
92 245
94 940

You might want to read this post or the complete thread for the first page of a road map to repairing your system. Amarion is very knowledgeable and may prove to be a good contact source.

https://www.brickboard.com/RWD/volvo/1616010/220/240/260/280/opinions_ac_compressors_please.html


The answer to whether the compress can become hydro or hydra locked is yes but only temporarily as the liquid refrigerant will boil off from a liquid and back into a gas when the compressor warms up.
This symptom is called slugging the compressor with frost back or over loaded liquid on the low side return line.

If the compressor is hit with excessive amounts enough times, that it can break components inside.
In this case, it stays stopped.

The other scenario is like the one in the post above.
It could be just old age? Lots of things to be considered are going on here.


You appear not happy with a certain shops work and the latter post might be the case?

I am curious about the evaporator size? The '93 came with the larger evaporator from the factory!
That story from the PO does not jive. Maybe it was defectively?
This system may have been installed after factory delivery by a dealer or another shop?

In any case, there is plenty of advice available to get you through this!

I commend you for taking the effort to be better than the last guy, known or unknown!

Phil