A/C problems on my 89
Thread Starter
6th Gear
Joined: May 2003
Posts: 6
Likes: 0
From: Las Vegas Nevada
A/C problems on my 89
An acquaintance who is a mechanic kept my 89 for a day and test drove it. We both noticed that the temperature gauge climbed steadily into the 240's, and probably would have kept going, when the A/C is switched on. Even on the freeway, it hovers around the 240 mark. With it off, temperature falls steadily back down and stays at about 190. The outside temperatures here in Las Vegas are currently over 100, 90's at night. He claims the compressor is just old and tired, putting too much load on the engine. Can this be true? Has this happened to someone else, instead of just outright failure of the compressor? :cool:
Instructor
Joined: Apr 2003
Posts: 224
Likes: 0
From: Gilbert Arizona
Re: A/C problems on my 89 (tangogreg)
Hi,
I've had exactly the same problem with my '89 coupe -- my engine temperatures have followed the exact same pattern. And, I live in Phoenix so I deal with the same outside temps that you do, for the most part. Unfortunately for me, though, two weeks ago my a/c compressor pulley siezed and it destroyed the compressor. $1300 later, the entire a/c system has been restored back to new. The unit is a new AC Delco unit, *not* a remanufactured unit.
Since doing the new compressor, my temps have not changed at all ... it's the same pattern: on the drive home from work at 5pm, stop-n-go traffic, in 113 deg. heat, the temp crawls past 240. I switch off the a/c, and temps drop drastically.
I've done lots of investigation, and finally discovered a ton of garbage has built up between the radiator and condensor. Unfortunately, it's very difficult to catch this because of how little visibility there is between these two units -- it's all closed up by the shroud. If you look carefully with a flashlight thru the holes in the shroud area just below the radiator cap, you're likely to see at least some junk. And ... if you see *any* junk, you can be sure there is a lot more that you're not seeing.
What to do? At a minimum, the top of the shroud needs to be removed so you can get down in there and vacuum out all the accumulated trash/leaves/paper/junk/etc. Removing the top of the shroud looks like it's a pain in the butt, but not too bad. The optimal solution, however, is to remove the radiator entirely, clean out the area (as suggested above), then throughly clean the radiator in between the fins ... being careful to sit down and straighten all fins. There is an excellent article in the tech tips area here on the forum that explains how to do this:
How to Remove and Clean Your Radiator
https://www.corvetteforum.com/techti...D=53&TopicID=2
Depending on your situation, you may consider taking the radiator down to a radiator shop and having it rodded/cored. If you're doing the R&R yourself, then it's not too expensive to have them do this ... and it's well worth the effort.
While your at it, you'll of course need to drain the entire system of coolant ... so it's an opportunity to flush the entire system and install new hoses. Good insurance.
If your plastic overflow tank is really gunked up, it's probably worth the time and effort to simply buy a new one instead of attempt to clean the inside of the existing one (which is nearly impossible!). A new tank can be had for like $15-20 if you shop the local dealers ... a little bit more thru MAD or Eckler$. I've already bought a new plastic tank and cap w/dipstick in anticipation of doing mine soon.
But, I have not yet done any of this ... I'm watching the temp at drive-time and shutting down the a/c when it gets to 240, and will get these tasks done sometime soon. Unfortunately, I have a couple of other more important issues to iron out with the car before I can dig into this one :D
There has been quite a bit of activity with several posts on this subject lately -- both here (Tech/Performance) and in General Discussion. So, if you want some more input, do some searches and you'll find quite a bit of material posted in the past couple weeks. However, you'll find that most of it agrees with what I've said here.
Good luck, and let us know how things go. And ... sorry for being long-winded, but I feel "qualified" since I am going thru this and just finished investigating the issue :yesnod:
[Modified by SkunkCar, 3:04 PM 6/29/2003]
I've had exactly the same problem with my '89 coupe -- my engine temperatures have followed the exact same pattern. And, I live in Phoenix so I deal with the same outside temps that you do, for the most part. Unfortunately for me, though, two weeks ago my a/c compressor pulley siezed and it destroyed the compressor. $1300 later, the entire a/c system has been restored back to new. The unit is a new AC Delco unit, *not* a remanufactured unit.
Since doing the new compressor, my temps have not changed at all ... it's the same pattern: on the drive home from work at 5pm, stop-n-go traffic, in 113 deg. heat, the temp crawls past 240. I switch off the a/c, and temps drop drastically.
I've done lots of investigation, and finally discovered a ton of garbage has built up between the radiator and condensor. Unfortunately, it's very difficult to catch this because of how little visibility there is between these two units -- it's all closed up by the shroud. If you look carefully with a flashlight thru the holes in the shroud area just below the radiator cap, you're likely to see at least some junk. And ... if you see *any* junk, you can be sure there is a lot more that you're not seeing.
What to do? At a minimum, the top of the shroud needs to be removed so you can get down in there and vacuum out all the accumulated trash/leaves/paper/junk/etc. Removing the top of the shroud looks like it's a pain in the butt, but not too bad. The optimal solution, however, is to remove the radiator entirely, clean out the area (as suggested above), then throughly clean the radiator in between the fins ... being careful to sit down and straighten all fins. There is an excellent article in the tech tips area here on the forum that explains how to do this:
How to Remove and Clean Your Radiator
https://www.corvetteforum.com/techti...D=53&TopicID=2
Depending on your situation, you may consider taking the radiator down to a radiator shop and having it rodded/cored. If you're doing the R&R yourself, then it's not too expensive to have them do this ... and it's well worth the effort.
While your at it, you'll of course need to drain the entire system of coolant ... so it's an opportunity to flush the entire system and install new hoses. Good insurance.
If your plastic overflow tank is really gunked up, it's probably worth the time and effort to simply buy a new one instead of attempt to clean the inside of the existing one (which is nearly impossible!). A new tank can be had for like $15-20 if you shop the local dealers ... a little bit more thru MAD or Eckler$. I've already bought a new plastic tank and cap w/dipstick in anticipation of doing mine soon.
But, I have not yet done any of this ... I'm watching the temp at drive-time and shutting down the a/c when it gets to 240, and will get these tasks done sometime soon. Unfortunately, I have a couple of other more important issues to iron out with the car before I can dig into this one :D
There has been quite a bit of activity with several posts on this subject lately -- both here (Tech/Performance) and in General Discussion. So, if you want some more input, do some searches and you'll find quite a bit of material posted in the past couple weeks. However, you'll find that most of it agrees with what I've said here.
Good luck, and let us know how things go. And ... sorry for being long-winded, but I feel "qualified" since I am going thru this and just finished investigating the issue :yesnod:
[Modified by SkunkCar, 3:04 PM 6/29/2003]
Race Director
Joined: Sep 2000
Posts: 12,182
Likes: 1
From: Partying with the Cowboys cheerleaders in Mt. Olive, New Jersey
Re: A/C problems on my 89 (SkunkCar)
That's a pretty writeup there, Steve. :cheers: I for one, always appreciate fellow 'vetters who put the effort into explaining things in detail. :thumbs:
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: A/C problems on my 89 (SkunkCar)
Good advice. Here's one mor tip that will make your life a lot simpler on the re-install of the plenum:
After you get the six little bolts out of the plenum, switch the "Tinnerman" nuts from one half to the other. That will allow you to gain access to the little bolts (6mm?) from the INSIDE of the rad plenum by lying down and using a nut driver from the rad inlet. Once you get into it, it will become pretty obvious. (Sorry no digi cam)
After you get the six little bolts out of the plenum, switch the "Tinnerman" nuts from one half to the other. That will allow you to gain access to the little bolts (6mm?) from the INSIDE of the rad plenum by lying down and using a nut driver from the rad inlet. Once you get into it, it will become pretty obvious. (Sorry no digi cam)
