cooling fans

[Taz's Master]

When the car's running they work fine. Temp goes to 3/4 they kick on and the temp goes right back down. But I remember that they used to continue running after I shut the car down. Now they don't. Is my memory bad, or is this something that I can fix?

[swimmingly]

I have the same 'problem'. I'm on a limbo as to whether I should purchase a new relay or not since they're expensive..

[drew1]

Don't worry, they will probably run a while after shut off on some hot days this summer. The temp switch in the radiator cuts them off & on. A low swithing point temp swith can keep your fans running, I heard of batteries going dead because of this.

[mlue]

Originally posted by swimmingly
I have the same 'problem'. I'm on a limbo as to whether I should purchase a new relay or not since they're expensive..

Swimmingly, you should buy one of these... .

http://www.pap-parts.com/prodinfo.asp?number=944%20615%20104%2003

[Frank B]

I had the problem of the fas running and draining the battery, which was caused by a faulty Thermo-fan switch. Swap it out and save yourself a lot of hassle.
Frank

[Dan in Pasadena]

Here's a picture of the thermofan switch. Just bought it from our host. It came with the green fiber washer but I was told here to use the crush washer....I assume INSTEAD of, NOT in addition to the fiber washer, yes?



I think I paid about $10 for this. The relay is $129 from our host.

[swimmingly]

Dan, I bought one from a local supplier. Mine only came with the fiber washer. Yours is a 92/102, right? I think the place I got mine from must've gotten mine incorrect because now I have a 85/92. I just installed it anyways, hoping that:
1. the new switch/gasket would stop the small leak I had
2. it would lower my temp.

Unfortunately, it did neither. But I haven't seen any negative consequences from using it except for the fans being on much more, so I just left it in there. I'd personally use the green washer, but maybe the metal ring is an update of some sort?

[mlue]

Swimmingly, I am courious about whats inside the thermo fan switch, if you have the old one and you have a grinder how about grinding it open so we can take some pics of the insides of our $10 overheat protection. I wish I had done that when I replaced mine.

[Dan in Pasadena]

Mark, I doubt you're going to find much in there, it's most likely just a bi-metal piece thateacts to the water temperature closing a little set of contacts. Nothing muc hto see or fix.

Swimmingly, I don't know those numbers you are referring to. The only numbers I've got are the ones you see on the packaging in the picture.

I think it was onwhippedpuppy (Matt) that mentioned using the metal crush washer in another thread. If you go on the Pelican catalog page for the switch, the crush washer is listed right with it. You can't QUITE see the words in the picture, but it says it is the same crush washer used for the oil drain bolt!

[mlue]

Originally posted by Dan in Pasadena
Swimmingly, I don't know those numbers you are referring to. The only numbers I've got are the ones you see on the packaging in the picture.

IMO the switch that you got with the lower temp settings are for an Audi or Volvo. There is good info to support the fact that the temp ratings of the thermo fan switch should be matched with the opening temp of the thermostat. It may make sence to have the fans come on early so that we always have cool air moving through the rad but that may put more stress on the electical system (battery and alternator) or maybe NOT.

Originally posted by Dan in Pasadena
I think it was onwhippedpuppy (Matt) that mentioned using the metal crush washer in another thread. If you go on the Pelican catalog page for the switch, the crush washer is listed right with it. You can't QUITE see the words in the picture, but it says it is the same crush washer used for the oil drain bolt!

The rad tank area that the thermo fan switch screws into can be made of plastic or metal. Could it be that the fibre washer is for use with the plastic tank and the metal one for use with the metal tank. In either case the torque specs are quite lite or you risk stripping the threads.

Yes, the crush washer is the same as the oil drain plug.

[Dan in Pasadena]

Mark,
The thermofan switch COMES WITH the green fiber washer in the same box. The metal crush washer has to be ordered separately for another dollar or two. But it is listed with the thermofan switch and says it is for both the switch and the oil drain plug on its packaging.

PS Now i get it, the "numbers" are the temp rating. Duh...sorry to be so lame!

[Jeeper31]

Did you have to drain your radiator to change the switch?

[Granite 944]

"Did you have to drain your radiator to change the switch?"

Only if ya don't wanna get wet. Drain enough to get level below the switch. Re-bleed of course.


My suggestion would be to use the green fiber washer. The aluminum crush one is more of a generic catchall thing. TORQUE the sensor to its proper amount (22 ft lbs)......either way you go. I've used both types on my earlies, and had problems with the aluminum one sealing up decently after getting up to temp. Hard to find that kinda slow, miniscule leak, by the way.

I have the lower set point thermo-fan switch in my wife's '85/1. Fans run way more than they need to. I'll be going back to the stock one, the next chance I'm in there. I think the ONLY reason one would need to go to a lower set point switch is if your trying to compensate (somewhat) for a nasty/plugged up radiator, or live in an are of extreme heat. Just my .002. Clark's garage. Good info.

[Frank B]

Also, consider going with a higher temp switch.
Reason I suggest that is sometimes in the warmer months, your car may never acheive the "Low" shut off temp required to cut the fans off, resulting in battery drain. That happened to me.
I also was able to get a new radiator from a local radiator shop for around $400.00.
and if you are draining your system ( which is a good idead anyway) remember to use the correct fluid for an alloy block.
Best

[GMingst]

Wait, I gotta ask this. All you contributors who are so concerned about running the fans continuously. If I lived in a hot climate and ran the AC all the time (and there are people who do) That runs the fans all the time too. Highway, Stop and go, whatever, they just run run run. A lower temp thermofanswitch would at least cycle on and off when your speed picks up and airflow increases as long as the cooling system is in good order. How often are you guys having fan failures?

regards
Graham

[Frank B]

no fain faliures.....battery drainage after we exit our cars....