Engine starting to run hot, fan clutch?

I have an '85 528e that is starting to run warm again now that the temperature has increased a bit. I live in the desert southwest, so keeping an engine running cool is a TOP priority of mine.

While I was driving for a while last night (at least an hour in stop and go traffic), the temperature gauge moved from the halfway mark, to the ¾ mark and was getting close to the 7/8 mark before I got on the freeway and it cooled right down again.

That tells me that the cooling system is working, and the fan may not be.

When I got home, I left the car running and popped the hood. The fan was running. I grabbed a rolled up newspaper and stuck it in the fan blades. Stopped the fan EASY. I heard that this is an indicator that the fan clutch needs to be replaced. I can get a new one for $64. Any idea on how hard of a job that is to replace?

I noticed that Bavarian Autosport sells a 32mm thin spanner wrench to help get the fan clutch off. Do I need that tool?

John

P.S. All of my good tools were swiped from my garage last year, so I'm left with a basic metric set of wrenches and a big-ass crescent wrench. I may need the "special" tool anyway.

Hi, Web.
Whilst hanging out on the unofficial BMW site, I found several people mentioning malfunctioning fan clutches. Seems to be common.
Congratulations on your diagnosis. Shouldn't be too hard to fix.
Flunky

Flunky,

Well, I was feeling pretty proud of myself. Then I took a look in the Bently manual and noticed some diagnostic tests for the auxiliary fan (the one in FRONT of the radiator). I go hmmmm...I don't remember ever seeing that moving. Ever.

So, after I drove the car and it got nice and hot, I parked it to see if the fan was moving. Nope.

This weekend I will run some of the tests (just bypass the sensors mounted on the radiator) to see if I can get it to turn over.

The best answer would be for the sensors to be replaced. A replacement aux. fan is a few hundred clams. I may not have time to wait for one to show up in the local pick-a-part junkyard. It's starting to get warm out here.

But, first thing this weekend will be to yank the thermostat for the summer.

Web

In the tool kit is a pair of pliers, called waterpump pliers.

Guess why they are called waterpump pliers?

The size of the fan clutch is 32 mm or 1 1/4 inch and it needs to be thin wrench to get to the nut.

The trick is the nut has reverse threads.

I would not remove the thermostat since a BMW runs like sh!t when the thermostat is removed.

It needs to get to 160 deg as soon as possible and that is the job of the thermostat.

Later,

Just a quick update since I actually got to work on the car a bit this weekend:

* I removed the thermostat. The bastard was nearly welded on and it took me about 90-minutes to get it out. I took my brother's advice and ran a micro-torch over the thermostat where it sat in the housing. Then jammed a big screwdriver in the center (I had already destroyed the spring/plunger thingy) and gave it a sharp whack. Out it came.

I ran the car today with no thermostat. Still ran hot in stop-and-go traffic. It just took longer to get hot.

I also jumped the temperature sensor relays attached to the radiator to make sure the auxillary fan works at both temperatures. It does. It also kicks on when the AC is running and was running when I pulled into work today. So, that rules out the auxillary fan for the moment.

I ordered a 160-degree thermostat from Bavarian Autosport and will install that this weekend.

I talked to the rep and he confirmed the rolled up newspaper test on the main fan. So, I have a new fan clutch coming as well. Interestingly, the Bently manual diagnostic for the fan clutch is to turn it by hand on a cold engine. If you can't turn the fan, the clutch is bad. I could turn my just fine, so assumed the newspaper test was faulty.

I'll report back next weekend to see if the fan clutch solves the overheating issue.

webhak,
the auxilary fan up front is for the AC, to keep from over heating whilst you try to keep cool.
The fan clutch actaully has fluid in it to act as a torque converter for the blades if the fluid doesn't pump well enough, the blades won't turn as fast as the engine itself thereby giving less airflow thru the radiator. You should feel some restistance when turning the blades with the engine off. New fan clutch should fix it. Typical GM car problem too.

Hi, Web-
Our cars seem to be malfunctioning in parallel. Now, my temperature guage says I'm running hotter than normal, but only when stuck in traffic, no problems on the freeway.
I'm still waiting on my membership card from BMW CCA so I can get my discount on the fan clutch, on-board computer bulbs, center bearing, etc.
Flunky
PS-Still haven't resolved my speedo problems. During the three minutes each week that my speedo functions, I've taken note of my speed and what gear I'm in, so at least I have a general idea of how fast I'm going from the tachometer.

Flunky,

Maybe our cars were twins separated at birth.

I put the new fan clutch in this weekend. Very simple job. I used some engine cleaner to clean the gunk off the fan while I was at it.

I also installed a new 71-degree (C) thermostat while I was at it and topped off the coolant.

Plus, added a new BMW emblem on the trunk after some punks pried it off a few months ago. Now the car looks MUCH better.

I took it for a test drive yesterday to check for leaks and to see how the temperature held up. So far, so good. The gauge got to the middle and stayed there and even started to drop as I was driving at higher speeds. I'll give it a week and report back to see if the running hot issue has been resolved.

BTW, I ran the diagnostic test again on the new fan clutch. If you'll remember, when I stuck a rolled up piece of newspaper in the fan blades, it stopped like a ceiling fan set on low...even though it was turning pretty good. After the new clutch was put in, there was a noticable difference. The fan damn near took my arm off this time. It's pushing a lot more air with the new clutch.

As far as the speedo goes...you guys aren't giving me much hope that I can resolve this issue either. I'll get under the hood in a couple weeks to look at that. Not a big issue now since the April repair project is the front brakes and rotor replacement.

Allrighty, here's an update of driving the car for a week with the new fan clutch: The temps are running much cooler overall, about 3/8 to 1/2. Sitting in traffic with a warm engine, it may creep up to 9/16 or so on the gauge.

That's the good news. Now for the interesting news: I was gone for the weekend and my wife was driving the 528 while her car was in the shop. She calls me Sunday to tell me that the car is running hot. Not overheating, but the needle is about 7/8 over.

Crap.

She has the car again today and told me the coolant light is on. So, I told her how to top off the reservoir and I'll see if that addresses the issue. I'd rather deal with a coolant leak than a getting into this troubleshooting business any farther.

Otherwise, my next step is to take a closer look at the auxillary fan temp sensors. Again, the car cools down quickly once it gets some air moving through the radiator.

Then again, I'm also open to suggestions.

Here's the final chapter in the saga: The radiator was plugged/corroded. With a new one popped in, the temp gauge has barely cracked the halfway point and is often running about 3/8 for most of the morning commute.

I had purchased a "cheap" radiator from a local radiator shop instead of paying the extra dough for one from Bavarian Autosport or the local BMW parts dealer. The first radiator I purchased from these dipshits was from South Africa and had a pinhole leak between the transmission cooler and main radiator core...resulting in a new transmission for me.

The second radiator came from Thailand and had developed a leak (discovered once it was pulled) and only lasted two years.

webhak, I have no idea about your fan clutch/cooling problems, but it sounds like you're making a bit of progress and know/have learned a lot more than me!

Regarding your speedometer--maybe I can help. I had a 1986 528e from 2000-2002. Provided it's not a fuse issue (ONCE I was driving and all of a sudden the needle just dropped to 0 and stayed there--immediately replaced a fuse and the issue went away for good), you probably have a bad SI board. I believe these are costly to replace, and in my mind it's not worth it.

I had a few nonfunctional things in my instrument cluster (coolant temp., fuel economy and eventually odometer) and solved this by replacing the entire cluster with a used one for $75. Of course the odometer reading was different, but... It's really quite simple--remove the two screws that go into the underside of the hood over the cluster, and pull it out after you've removed the steering wheel (pop off the enamel emblem and unscrew the big bolt that holds it on--this is assuming you don't have an air bag in your car). My mechanic installed the new cluster for me, but I think it's just a matter of disconnecting and reconnecting wires.

4-door Flunky, I just joined BMWCCA too, and got my card a couple of weeks ago! I got my first "Roundel" today. I'm in the National Capital Chapter (DC). Where are you?

csieminski,

Actually, my speedo problem was also resolved by the mechanic when the radiator was replaced. He told me that my brake lights were out and when he went to replace the bulb, he noticed that water had collected in both brake light housings and corroded the sockets. He also mentioned that some of the wiring in the back was getting a bit "messy." From what he told me, he replaced the sockets, cleaned up the wiring and replaced all of the fuses as well as tightened the fuse clips.

This fixed the non-working speedo, odometer and radiator and also the short that had killed my radio and left the "check brake" light continually on in the overhead computer.

Looks like I will have to get some new gaskets for the brake light housing.

Great! Killed a lot of birds with one stone. Brake lights can be so problematic on E28s; it's good to see you may have resolved this (as well as the overheating issues and speedometer).