Why don't she like the AC?

[TheBlackMoon]

Somebody PLEASE tell me what would cause a car that runs perfectly fine all the time to suddenly want to overheat if the AC is on, especially in stop & go traffic. <BR>She's a '90. I've checked the radiator fluid level, and she does give cold AC (non-converted). No leaks that I can tell. Always runs at 1/2 max without AC (as is normal). Thought it was due to the hot weather. Ran hot when it was kool the other day and in bumper to bumper traffic on I-695. Never overheats otherwise. Won't overheat in idle. Radiator fluid circulating normally.<P>HELP!!!

[Guest]

It could be that the cooling fan isn't coming on with the AC. Even with a cold engine, the fan is commanded on when ever AC is requested. Start the car cold, turn on AC and after about 30 seconds the radiator fan should come on. <P> Good luck, Jim<BR>

[Guest]

I have a similar problem, just a little different. My AC works fine, but not if I push the AUTO button. I could whack it with a hammer and nothing would happen. In order for me to get cool air, I have to push up on the FAN button.<P>The BI LEVEL button does not work either. These two went out about six months after I bought the car. My mechaninc is stumped and quite frankly, I can learn to live with it. As opposed to having him tear my car apart and still not find out what's wrong.<P>I don't know where your located (I'm in North West Ohio) but at least the summer is half over, and it's not baking hot like it was at the first of the month. <P>I wish you luck with your dilema.

[Guest]

Whole section in the book (shop manual)on this. Have to say here's one place those of us with '88 and '89 models have it in spades over you guys with the "later models". Ask your Buick dealer parts guy for the phone number of the Helm Co. They sell the shop manuals for these rascals and you can't get anywhere without one. Agree with the guy talking about the cooling fans. Also check to see how many you have. 89's have two, with two speeds for each fan. Now you can see why the manual is so important to ensure all modes work properly.

[Guest]

Very similar problem on my '89 and it was because the air conditioner cooling fan was not coming on. (that is the one in front of the radiator) The probem was the fan control relay (available from Buick) in the under the hood relay center. I agree, the shop manual pointed me to the problem easily..I have one other advantage, two '89 Reattas..You can't imagine how many times I have swapped parts from one to the other to diagnois a problem.

[TheBlackMoon]

Hey, my thanks to everyone. <BR>I have a manual; haven't taken the time to look at it yet. I'm going to start checking it out this weekend, but I wanted to ask to make sure I'm on the right track. Glad I did. Didn't know that the other fan was supposed to come on (the one at the radiator) and got nervous when I saw the other on as normal. Now I know (and the dealer will too ) Once again, thanks a bunch and LOL.

[TheBlackMoon]

Now I'm PO'ed!!!<BR>She only has one fan; it's the one in front of the radiator and, like I said before, it's running just fine. This is ridiculous! <BR>I'm getting frustrated again! Thermostat would effect normal operation. I heard the fan is a two stage/speed. Is this true? Could it not speeding up cause it to overheat? How would I check for that? Any suggestions I sure would appreciate?

[Guest]

I has the same problem with my Saab 99, loved that car.<BR>It turned out to be the radiator being gummed up. Not totaly clogged but enough to cause problems.<BR>I had the radiator boiled in some solution and got 10 more years out of her.<BR>Natasha<BR><P>------------------<BR> <A HREF="http://www.ciscobot.com" TARGET=_blank>http://www.ciscobot.com</A>

[Guest wally888]

RE. A/c and no cool from auto(selected).Your a/c / defrost door is closed due to being stuck( I doubt) or bad door actuator.<BR> I have replaced 2 actuators on my 89! 1st was up/down,most recent was a/c / def.<BR> Re. fan problems.I had a shorted wire in the center consol that kept fan from coming on.Took forever to find it!<BR> Overheat: May get some help by washing radiator vanes clean w/ water hose or compressed air.Be careful not to bend any vanes.If fans run normal you might try flushing but will probably have to have radiator removed and boiled out.<P>------------------<BR>

[Guest wally888]

Should have mentioned:If you have no cold air out dash vents, select defrost.If you have cold air on defrost (out defrost vents)then a/c /def door is problem.

[Guest]

There should be two fans, and both should operate at the same time. The low speed operates the fans in series and high operates them in parallel. If you look at the wiring diagram in the book, you will see how this is done. There are three relays that operate the fans and if any goes bad, the fans will not operate correctly. They are common Bosch relays, and any of them with five terminals will plug right in. All of them are the same and can be switched around to see if the operation changes.<P>------------------<BR>Hal, btk@vbe.com

[Guest]

Recently had a similar problem, turned out the water pump was going, was trying to figure out what was happening then lickily it started to leak fluid out of the pump shaft seal, dealer wanted $70. for H20 pump, discounted from $100. list, I bought mine at advance with lifetime warranty for $27. easily replaced. I did it myself and I am certainly NO mechanic, but it was a low cost fix for a nagging problem. I use a 50/50 mix for coolant and replaced with new after draining what was left of the old. Good Luck.