Hello folks,
We have a 1987 260E with less than 45k. The AC is not really cold, kind of luke cold. I know that on the newer cars outside temp has to be 86 degrees or higher for the aux fans to come on, is this true with the 87 model? Thanks for your help.
Brian

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Brian W. Heitman

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Outside temp has nothing to do with the aux fans.

You need to put gauges on the a/c system and give us system pressures for us to go to the next step of diagnosis.

Good luck,

If it's really cooling a little bit and you're not just feeling it's cooler because of the moving air, then the refrigerant charge is probably just a little low. Hopefully, the car has not been converted to R134a. WHATEVER you do, don't let some bonehead talk you into having the conversion done. And don't try to mix refrigenants. That's a good way to destroy a compressor.

There are several websites where you can get a license to recharge with the original R-12 refrigerant. It will only cost you $10 or $15 for the license and you'll learn more than you ever wanted to know about your AC. You'll also be able to buy a can of R-12 from the local parts guy and top up your system, just like the old days.

Here's one site EPA Test . Printable study guide is free, the test & cert is $15. I've heard of others for less. Well worth it IMNSHO.

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Norm in NJ
Next oil change at 230,000miles

Thanks for your replies. My friends 87 260E's AC cools the interior very well while the car is in motion going down the highway. My SL was doing the same thing, the AC was not really cold while in traffic, I discovered through the StarTek that the Aux fans do not engage with the compressor if the outside temp is below 86 degrees F. unless the Freon temp sensor kicks it in, or the engine temp sensor. The reason I think for this is because the Primary engine fan sufficient enough to keep the AC cool if the temp is 86 or less, my problem was my fan clutch, after replacing that it is ice cold. I didn't know if this was the same way for an 87 model. I have purchased a fan clutch for my friends 260E, as I can see the orignal has no friction whatsoever, so I will replace that and we will see if his cooling improves. The pressure in the AC system is correct as the pressure switch near the drier is in a closed position. The freon temp sensor however will be my next step to testing since I would think if it is not cooling enough it should engage the fans. I think we should also clean the condensor as well. Whether the fan clutch corrects the AC problem or not, it is worn out and needs to be replaced anyway. I will keep you posted, thanks and have a great day!
Brian

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Brian W. Heitman

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The aux fan is not supposed to come on with the compressor. It's purpose in life is to be a safety factor to prevent excessive high side pressure in the a/c system or excessive engine coolant temperature. It will have little to do with a/c cooling capacity except for the fact that it keeps the a/c from being destroyed which will indeed effect cooling.

As mentioned, the most likely problem is a low charge. Give us the pressures and we can help you diagnose it. The first step in troubleshotting a low performing a/c system is pressure readings.

Good luck,

Thanks Larry,
I will check the pressure and get back with the results, I don't have R12 gauges, only R134, I will have to ask around to see if someone has R12 gauges that I can borrow. Or can you buy them at the parts store? I followed the procedures for a sight check from the Startek data, I thought that was sufficient. Thanks again for your help!
Brian

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Brian W. Heitman

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If you know someone who does residential/commercial a/c work they will have the gauges you need. The same gauge set is used for R12, R22 and R502. These guys regularly use such gauges.

Good luck,