Behr Air Conditioner query

[yogiysh]

It's getting pretty hot here in Sydney so I've started to use the AC. I've been using it regularly now for a week and its been great - it pumps out very cold air.

After last weekend's trip out of Sydney I've noticed some noise when I which the AC on as well a more load on the motor at idle and low speeds compared to when I started to use it a week ago.

The noise stops at higher rpms and I don't notice the load (of course due to the all ready higher rpm).

It is still pumping out very cold air but I'm a bit concerned if the AC compressor needs maintenance/lubrication top up???

The MB Star Classic CD is a bit ambigious - describes how to drain but very sketchy on how to refill but clear on determining the volume of oil replacement.

If I do decide to attemp to refill the oil, do I need to get the Liquid Air refrigerant(freon replacement) professionally drained first? Is the oil resevoir a seperate system from the refrigerant resevoir(I've got my fingers crossed...)?

Thanking you in advance, looking forward to your advice.

Ysmael

[AusMBtech]

What engine do you have?

It may not be compressor noise that you are experiencing. It may be a worn drive belt, belt tensioner of belt tensioner shock which will all make noise when the a/c is on at idle.

To drain the oil out of the compressor would require the removal of the compressor or a comprehensive flush of the system with nitrogen. As long as you don't have a leak, I wouldn't worry about it.

[yogiysh]

Hi Alex,

You might have a point, I've just raised Tobias up on the stand and poked my head underneath and the noise (squeaking) isn't coming from the compressor but I still can't isolate it (...ran out of time for today). It seems to be coming from the AC clutch pulley.

Thanks for the advice, will continue looking tomorrow.

Cheers,

Ysmael


- the engine is the 3.5L V8

[nachi11744]

Hello,
Spray some water onto the v-belt that drives the a/c compressor and check if the noise goes away. If you have not replaced ALL the v-belts and there is no evidence(receipts)of it having been done in the last two-three years, just junk all and fit new v-belts.
Hope that helps.

[300SDog]

Or if you go the oil change route, might not be a bad idea on the '72, freon garage can drain the system and store the gas and then put it back in.

[yogiysh]

Okay, here's what I tried - I sprayed the v belt with some water while the clutch was engaged and it actually made the belt slip with a loud piercing squeal and the compressor pulley coming to a halt. Thanks nachi11744 for that simple tip.

So it's obvious that the belt needs to be tensioned a bit but if this fails I will replace the v belt (I can't find any record of when the v belts were last replaced...) - looking at the set up it looks straight forward but I'll just have to read up on how to do this first...

Cheers,

Ysmael