Coolant temperature too high
 

A trusted Indy replaced both auxiliary electric cooling fans last week. Now while waiting at a traffic light with the A/C on and 95 F outside temp, the gauge rises quickly to about 120 C, the auxiliary fans are on, and the A/C blows warm air. Once moving the temp falls to about 90 C, and the A/C produces cold air. This is a '94 E320 with 145,000 miles, with possibly the original radiator.
What's happening?
Mark

My friend just had his 1996 W210 aux fans done at a "trusted indy" and they plugged them in backwards so they were blowing the wrong direction. His car did not cool well, even when moving, since I guess the fans were working against the air flow. Anyway, I don't know if that is your problem, but it sounds like it might be an easy mistake.

Use a small piece of newspaper and from the front of the car check if the paper is getting sucked in or blown out. It should be sucked in, the air should flow from outside to inside the engine compartment.

Just look at them..they have a big Rotation Direction Arrow right on the front of them...Pretty Simple.
[ CW looking from the front is correct]

You can't plug the connector in backwards; there is a key which prevents this.

Was that an aftermarket assembly, by any chance? I bought one a while back that was wired in reverse. I fixed that problem, but the fan failed nine months later and I replaced the OEM motor in my original assembly.

It may have been, I never saw the thing. I just know that it happened to my friend's W210, so I thought it could be the same on a W124. My friend simply went out and swithced it himself in the parking lot while he was here at work. He said he just pulled the connector and reversed it to plug it back together. His car is running nice and cool now. Based on what you said, I guess it must have been aftermarket. I know my indy will use aftermarket things, but he usually asks if I care and indicates how much more it would cost to get the part from the dealer. For example, I saved about $700.00 or $800.00 on the exhaust, by going with a 2-piece aftermarket thing. It seems OK so far.

i had the same problem until yesterday. i had the fan clutch replaced on thursday and didnt get the cooling level i wanted. i flushed the radiator with MOC fast flush and put in a new thermostat and now i am runnin comfortable around 90 degrees

My fans are turning CCW. I can't find the connections to reverse them. So I'll return to my indy tomorrow am; should be an interesting discussion.
Thanks to all.
Mark

Apparently the connection on AFTERMARKET fan wire has the same 'impossible to screw-up' plug as has the MB side. And, the fan was wired incorrectly at the factory - just as someone suggested earlier. Indy fixed in a few minutes. However I'm disappointed they didn't check the rotation before they initially released it to me.
regards,
Mark

<<However I'm disappointed they didn't check the rotation before they initially released it to me.>>

Very few are thorough today.....it's a shame....

From what I have seen, everyone is just in too big of a hurry. That may be OK for a very experienced mechanic, but it definitely isn't good for someone less experienced. I suppose they have to move on to the next thing to make enough money.

I do worry about getting my car fixed properly, once I decide to do the head gasket and the front timing cover. I just wonder if they will take enough time or have enough experience to get the things done properly. If I ever have to get the evaporator replaced, then that will really be scary.

For me, I think that is the real liability of hanging onto my car rather than just getting some newer Honda or whatever. If I knew I could get an experienced honest mechanic to take his time and fix things properly, I'm sure I could keep this car forever. I am willing to pay. That is why I was originally willing to hang in there with the Dealer. I rather liked the way they simply replaced things with new parts whenever there was a problem and I thought they had very experienced mechanics. Unfortunately, it turned out that the dealer doesn't really have mechanics that are experienced with my "old" Benz. The shop foreman actually told me that during my last visit about a year ago when I had my shift flair. He told me there would be lots of beautiful cars like mine in the junk yard because they are just too expensive to repair. :( Thanks to the forums, I learned about the vacuum modulator and fixed the thing myself with a simple adjustment.

I have a very honest indy, but the shop has changed from father to son ownership and I think there is more and more work being done by less experienced mechanics that work in the shop. The boys are great and I really trust them, but they are not Benz specialists and they may not even be the ones that work on my car. They were not willing to mess with the transmission when I asked about the shift flair. There is also a Benz specialist near by, but I'm not sure I could ever feel as comfortable with him as I do with my present indy. I 'm sure he knows my car, but I wonder about other things. :confused:

A problem in a large shop is the actual part R&R is turned over to a Wrench ..[ My Dealer/Tech friend calls them "Z-Techs".]
A thru Z... "A" being great and "Z" being the new kid..

"Give this one to one of the "Z Techs" ..:)

So, the car gets diagnosed by someone who knows the Tech end, but the part gets changed by a guy who doesn't..and you wind up with a set of installed fans that run great, but backwards.....