AC Problem

[laxman21]

Does the compressor not cycle if there is no refrigerant in the system?

Ac was not cooling. Wanted to check ref. level so I was runnig AC for 3 minutes to check pressure. Noticed the comp. wasn't running.

The was no pressure when I checked the low side with a gauge.

99 blazer.

thanks

[BlazerLT]

It will still cycle, but it will switch on and off quickly.

Also, you need to know that the system needs oil in the refrigerant too. With no oil (like when the system pressure is low), there is no oil going to the compressor and this will eventually ruin it.

[laxman21]

Well, I decided to try addind some 134. Guess what? the compressor started running as soon as I added it.

When,using the guages to add 134, do you go by the capacity on the sticker under the hood(12 oz) or by the pressure reading on the guages?

I also added a can of oil(I think half made it in) and a can of the stop leak and seal with the red die and a couple ounces of oil.

Should add more oil?

[tom3]

Probably good to go as is. Add refrig untill the compressor runs pretty steady and air is cold. Not over the amount shown on the tag in any case.

[BlazerLT]

Originally Posted by laxman21

Well, I decided to try addind some 134. Guess what? the compressor started running as soon as I added it.

When,using the guages to add 134, do you go by the capacity on the sticker under the hood(12 oz) or by the pressure reading on the guages?

I also added a can of oil(I think half made it in) and a can of the stop leak and seal with the red die and a couple ounces of oil.

Should add more oil?

You add it until you reach the safe measurement on the gauge.

[laxman21]

Originally Posted by BlazerLT

You add it until you reach the safe measurement on the gauge.

It's in the green while running. It goes up to the edge between yellow and red when I shut the engine off.

[Turbocpe]

Just FYI, the GM manual states, that basically, if there is a massive discharge on the low side, that the cycle switch won't close, so the compressor won't run. This protects the compressor, from lack of oil (due to lack of freon), I'd guess.

[BlazerLT]

You have to have the AC on MAX and the fan on HIGH while charging.