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A/C And Coolant Temp

bhaubold on Thu April 24, 2008 9:09 PM User is offline

Year: 1990
Make: Chevy Truck
Model: K1500
Engine Size: 5.7
Country of Origin: United States

My 90 Chevy pickup has 232,000 miles and all is well except the A/C. It cools just fine, and my cooling system seems to be working fine. But, lately when the A/C is on, the coolant temp starts to rise more than it has before. All chceck out ok on cooling side. The compressor seems to be making some noise. With this kind of mileage, what could I be in for.

Also, I would like to do as much of the work as possible. Would it be wrong to ask a shop to discharge the system, let me install new parts, then have them charge it?

Thanks for your help,

Bob

bohica2xo on Thu April 24, 2008 11:43 PM User is offline

Replace the fan clutch with a new OEM oe AC Delco unit.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

bhaubold on Fri April 25, 2008 7:17 AM User is offline

I was thinking about the fan clutch. It seemed to still have resistance to spin freely so I thought it was ok. But now with a recommendation, I will replace it this weekend.

Thanks for your help,

Bob

oznznut on Fri April 25, 2008 8:39 AM User is offline

And as said above, be sure to use a factory, OEM, clutch---NOT a cheap chain store aftermarket one. Yes, it will cost more, but it this case, you getwhat you pay for.
Dave

bohica2xo on Fri April 25, 2008 11:47 AM User is offline

Sorry for the short reply, I was on the road.

Your fan clutch is the number one suspect with the symptoms you describe. When the vehicle was new(er), there was no way that the A/C could raise the coolant temperature. Now that the system has 200k on it, it has lost some capacity, and has even less ablity to transfer heat than when new.

You may indeed have other A/C issues, but the fan clutch is where you start with this one. With decreased airflow, the high side pressure climbs & the compressor works much harder. This is probably the reason you are hearing the compressor. As long as this condition has not been ignored for a long time, the compressor may be fine once you get the airflow problem solved.

While you have it apart to replace the clutch, be sure to clean the air path completely. Small bugs, debris etc. can lodge deep into the fins on both the condensor & radiator - and restrict the airflow. If you put a droplight in the fan shroud, and look through the condensor & radiator from the front you will see what sort of crud is in the air path.

I use a surfactant like Simple Green, or Zep Citrus cleaner, at full strength. Spray it deep into the fins on a cold condensor or radiator, and let it soak for 5 minutes. Flush it out with a low pressure garden hose. Avoid high pressure washers, because you can easily bend the fins flat on your condensor. Straighten any damaged fins you may have carefully. You may need a couple of soak & rinse cycles to get it all out. If you live in a place with with a lot of insect activity (clean your windshield daily?) you have plenty of bugs packed in there. The surfactant will dissolve the little buggers, but it takes a few minutes.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

bhaubold on Fri April 25, 2008 1:42 PM User is offline

B,

Thanks for the excellent reply. I will indeed purchase an OEM fan clutch at the dealer. I've also noticed several fins on the condenser needing straighting. Will clean it at the same time.

Thanks again for the excellent advise,

Bob

bhaubold on Fri April 25, 2008 8:59 PM User is offline

Ordered a new fan clutch at the dealer today. Will have it Monday. Wanted to ask one more question. I mentioned that the system was noisy. Today I open the hood and took a listen with the a/c on. It seems the compressor is cycling on and off, on and off. Still gets very cold. Is this normal?

Thanks again,

Bob

brickmason on Fri April 25, 2008 10:11 PM User is offline

After the interior of the vehicle is cooled down, then its normal for the compressor to short cycle.



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Just another brick in the wall

Had a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil

bhaubold on Fri April 25, 2008 10:24 PM User is offline

Thanks for your help,

Bob

iceman2555 on Sat April 26, 2008 2:46 PM User is offlineView users profile

The noise issue and the cycling could be an area of concern. R4 compressors are a bit 'noisy', however, if the compressor is cycling,rapidly, and the compressor exhibits more than an acceptable amount of noise, this could be the result of an undercharged system. Consider that the OE fan clutch is perhaps a bit weak, and the excessive temperatures of the engine/cooling system, it is entirely possible that the system may have possibly released some refrigerant due to excessive high side pressures.
Once the fan clutch is replaced...perhaps it is time for a system recover and recharge...or at least post some pressures and let's see what is happening.
Also.....GM DOES NOT make their own fan clutches.....they are produced by an outside source.....so spending the extra cash for an GM OE replacement fan clutch maybe an unnecessary expense. Just food for thought.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

TRB on Sat April 26, 2008 3:42 PM User is offlineView users profile

Who is making them? I have tried the Hayden ones in years past and they preformed poorly.

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Contact: ACKits.com

bhaubold on Sat April 26, 2008 7:50 PM User is offline

I'm not an A/C mechanic, so can't perform the work. What would be a going price at an A/C shop for a recover and recharge. I'm here in northern Calif. where EVERYTHING is expensive.

Thanks for the reply,

Bob

Cussboy on Sat April 26, 2008 8:11 PM User is offline

Tim - I've been using Hayden fan clutch in my Mazda truck since 1994; it was lifetime from Pep Boys. They seem to last 6 years here in Arizona. Amazed that dealer didn't have one in stock for a 1990 truck, like there aren't many of those on the road.....guess times are tight, got to keep inventories of parts low....

TRB on Sat April 26, 2008 8:31 PM User is offlineView users profile

Quote
Originally posted by: Cussboy
Tim - I've been using Hayden fan clutch in my Mazda truck since 1994; it was lifetime from Pep Boys. They seem to last 6 years here in Arizona. Amazed that dealer didn't have one in stock for a 1990 truck, like there aren't many of those on the road.....guess times are tight, got to keep inventories of parts low....

We just had high pressure issues a few years back using them. Used the Motorcraft or AC Delco fan clutches and the issue went away. But if its working on your truck I sure would not suggest making a change! You know it's getting warm around here today!

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

bhaubold on Sun April 27, 2008 9:56 AM User is offline

How much should a recover and recharge cost?

Thanks,

vdubspeed on Sun April 27, 2008 11:26 AM User is offlineView users profile

Quote
Originally posted by: bhaubold
How much should a recover and recharge cost?



Thanks,

It's $140 out here by Firestone.

my advice...have them recover it but DIY for the fill

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I

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