Thread: It's not the blend door

So my AC blows warmer on the drivers side than the passenger side. It's not hot like the heaters on but the passenger side is COLD and the drivers side is only cooler than the air outside. I changed the blend door yesterday (what a pain in the ass) and it didn't fix the problem. So what else could it be? A vac leak? A few years ago and I had the compressor repaired because it was leaking so it shouldn't be that. I don't know the inner workings of the system enough to have any real guesses.

your low on freon, fill er up

Check the high and low pressures on the system.

On some cars if the R134a level is low only the passenger side will blow cold. I know for sure the bonnevilles are this way.

Could just be clogged fins on the core... Buddy had something like that but with his heater, took a can of air to the heater core and blew all the crap out the other side.

I'll try the freon. I don't think anything is clogged because the heat worked fine this past winter. Could someone explain how to check and refill the freon on these cars? Or post a link to a write up?

buy one of them refill cans with a gauge, read the can.

I just use the hose and buy the cheap little 12oz cans and fill through the low side port.

The cans with a gauge are kind of pointless because they only tell you low side pressure and really the high side pressure is more important. You'd have to shove alot of freon in the system to max out the low side and do damage.

Adding 8-12oz should be enough to tell you if it works or not. You can keep the little can on the hose if you don't use it all, just spin the needle down untill it bottoms out.

Where is the high pressure port? I've found images of the low online but can't find a definitive answer for the high. Near the alternator? And do I have to worry about refilling the high as well or just the low?

You never fill on the high side.


One port should be on the firewall and the other is like behind the airbox or close to there.

The one on the firewall is the low right? Other must be high?

If the weather holds up , I'm local and have the tools you need

Originally Posted by SomeDudeAtHome

The one on the firewall is the low right? Other must be high?

Small one center of firewall is low. Just hook on a large can of A/C Pro w/gauge and you'll be fixed in a few minutes. Read directions. I know everybody already said all that, I am just supporting it. It's very simple, my 99s need it each year. I'm saying get the big can based on experience and your description.

I'm needing to do this, my A/C is starting to take longer and longer to get cold... Lol

Another question. So if I need to put another can in and may have to do this every summer doesn't that mean it's leaking somewhere? Is it cheap to just keep refilling or should I have it looked at?

most of the time if you look over all the lines you'll find a wet oily mess at a connection or where a sensor in in the pipe. find the dirty wet spot, 99% of the time thats your leak.

they also sell cans with dye in them to find the leak.

I'll look them over at some point. Does buying the cans with the leak sealer in it mess up the lines? I noticed pretty much all the bottles said they did that but it seems like using something like that could possibly gunk them up.

Before I had access to an A/C machine I tried those leak-stop cans a few times, they never managed to seal anything. I'd just stick with the straight R-134a. I can stand by the A/C dye though, that with a cheap UV light and some tinted glasses are what I use to find leaks.

Depending on how long this seems to last I might try the UV stuff. I'm hoping it gets me through this summer. Might go out and by another can since this one didn't get me to the top of the green section on the gauge.

I'd charge it with nitro and listen for the hiss. Replaced the faulty part / almost always the condenser / and pull a vacuum then recharge it

however you find the leak - just find it. It's stupid to keep re filling it