Auxiliary fans - Benzworld.org

hoser · 08-09-2005, 08:32 PM

Hi All:
While waiting in a drive through for a coffee today I noticed that the temperature was almost in the red on the guage! Just under the "120" mark. The AC was on full blast, outside temperature was 33C.

After driving for a few minutes with the heat on the temp dropped significantly, to a normal level of ~ 80C. After I arrived home I started the car again and let it run with the AC on. The Auxiliary fans did not come on at all. I assume that they should be activated when the temp goes to 100C or so. I checked the fuse and it's contacts and all seem well.

Any thoughts? Is this a "known" problem?

foxmktgrp · 08-09-2005, 09:02 PM

I had a similar problem with the aux fan on my 1988 300E. The aux fan wouldn't come on. My A/C wasn't working properly and when I had it checked it was low 6 ozs of coolant. After they filled the system, the aux fan started working again. It has worked fine ever since. Just an idea for you to try.

hoser · 08-10-2005, 05:07 AM

You know, my AC is a bit anemic too. It cools the cabin down a bit, but "it ain't no hell", if you get my meaning [:D]

I'll get that checked out. Thanks a bunch!

Other opinions?

bc2885 · 08-10-2005, 07:22 AM

Hoser...Tap on the front tip of your aux fan w/ a hammer to loosen up the action inside. My MB mech did that to mine and it was less restrictive. I opted to replacement though as i dont like a hot motor!

kggkgg · 08-12-2005, 06:45 AM

Put 12v on the fan to check it works. If it does then its probably the a/c pressure thats the problem.

Keith

Uboater · 08-14-2005, 05:55 AM

A/C pressure switch maybe bad , but you need to dump the charge on the system to change it . Your high temp sensor should kick in at 100-105 c , I am going with the other post ,on low coolant level .

taranch · 08-16-2005, 09:02 PM

Hello everyone,

Just drove down to Virginia Beach from Montreal with my 300e (~1400 km). My mechanic told me that one of the fans was kaput, but told me it shouldn't be a problem. It wasn't on the way down. Coming back however, the second fan died on me while visiting NY City. The temp shot up near the 120 mark and needless to say, the AC wasn't cooling the cabin. Came back and had 2 new fans installed. Now the car runs like a charm.

I hope it's not your fans ($212cdn/fan uninstalled)!

Good luck

rbadina · 08-17-2005, 04:21 PM

the fans are very important in an engine life. if they are not working properly, appears the risk of boiling and damaging the entire engine. so be cerefuly an be sure that every thing works well.

hoser · 08-17-2005, 06:08 PM

Hi All:
Update: Both fans were replaced ($424 CDN just for the fans!!), the system was swapped over to R134 from R12, a dealer recommended AC system sealant was introduced to the system, labor and checks, just under $1000 CDN. Ouch.

It runs perfectly now and the AC blows cold. No disconcerting rises in engine temperatures. All in all I am pleased.......I just hope that this is the last bit of open wallet surgery for a while! Thanks for the thoughts and ideas.