A/C hasn’t worked for 9-10 years. When it did work it wasn’t the greatest. Decided it’s time to fix it. I’m already going to replace the condenser and it’s fan since they were damaged in a mild accident in 2019. Probably replace the compressor and dryer as well. Any thing else? Should I flush the system also? This is for a 1999 Chevy 3500 7.4

 

I would flush it after all that time. You want to make sure the evaporator is good and clean because tearing the dash apart isn't much fun. Yeah, the compressor change is a good idea too. Just make sure you add the proper amount of PAG-150 oil to the system, pump it down to -28 to 30 PSI, and make sure it holds. I'd add some leak detector, as well.

Yeah, that receiver/dryer needs to go no matter what. They are not very expensive anyhow, and the desiccant is going to be full of moisture. It's just cheap insurance, so the system works as well as it should. You can buy the R-134A at Harbor Freight cheaper than at the auto parts stores. The can doesn't have the valve in it like most do these days, and no return charge either when it's empty, so no adapter is needed to use it.

 

I'm getting ready to do the A/C on my truck too. Not due to it failing but the compressor started leaking and want to replace it before it does fail. Figured since I already have the system open I would replace the condenser too. Which condenser are you going with? I order a TYC (which I've heard is pretty good) but second-guessing myself now. I called the dealer and since it's a 99 it's discontinued.

Also, While you have your system open you should replace the orifice if the condenser doesn't come with one. If you didn't have a catastrophic failure a flush shouldn't be required according to all the research I've done. Just a vacuum test and then recharge.

 

Drew50513, I am not sure which Silverado version/engine you have, but if it's a 1500 with a 5.3L engine, rockauto.com is selling Genuine GM OEM condensers (for manual controls HVAC) for under $100.

https://www.rockauto.com/en/moreinfo...t=6708&jsn=475

Good Luck!

 

Thanks for the feedback! Is there a decent compressor brand that you recommend that won’t break the bank? I’ve heard Denso but that’s over $400.

 

I’m not sure on the condenser yet. I usually do a lot of research and forums to try and get a better idea of what to get. Not sure if you know or not but O’Reilly’s has a loaner program which includes vacuum pump, pressure gauges and a system flusher. Since I don’t have to buy those I will spend the extra on a good compressor and condenser.

 

I have a 5.7 in mine but mine is a tahoe with rear air. I've looked the net up and down and this is as close to what I'm looking for. Unfortunately rockauto doesn't have the GM condenser. My A/C works great ice cold great which makes me think the condenser is fine. I just hate to take the OE out and put something that isnt going to work as good ya know.

I got a Delphi compressor same as the OE for around 200 I think it was.

I'm just kind of stuck in that hard spot whether to change it out because of its age and do everything at one time or just wait for it to go out and have to open the system up again.

 

OK on having a Tahoe. I've had good luck with Four Seasons new compressors - I have them in 3 different vehicles wit zero issues. I did have to replace a condenser in our 99 Buick Century and I used a Spectra Premium condenser I purchased at Autozone (lifetime warranty) and it fit in place just fine and works great.

I did talk at length with the Four Seasons Tech Support about replacing condensers, and was told by them that because of the darn near microscopic passages in modern condensers (relative to ones from pre-1990 vehicles) that if a compressor grenades, there is no way one can successfully flush a modern condenser to get the crap out. Hence replacement is best.

Good Luck!

 

Its possible not to do a flush, if the compressor didn't go bad and spread particles into the system. If it did, it would end up in the system, plugging the orifice tube up, which was mentioned here, to be replaced, which is also a good idea.

 

Rock Auto has the Denso for $279 USD. Also Delphi and ACDELCO in the 200 dollar range. Of course, lube any O-rings with PAG oil.