Cooling Fan On 325i

[Watchman]

hey guys,

My uncle bought a 1988 BMW 325i convertible.. it was a pretty good deal.. only $2500.

Anyway, we took it to get a few things done on it to a mechanic that was recommended by the guy we bought the car from. We had an oil change and refilled the AC gas. The AC wasnt working at the time.

Soon after we did that the mechanic said the AC will cool wel for now but a new compressor is recommended. And we were to back there on Monday (tomorrow). So we left the place with the AC turned on, and 20 minutes after we left the car started overheating. We went back there, and then the mechanic snooped around and said the Cooling Fan (for the radiator) wasnt working properly cos the Clutch of it was pretty much dead (over wear and tare and time)...

So we looked it up, and according to some sits this clutch is a viscous clutch. Meaning when the engine is over heating the liquid/substance in the clutch becomes more viscous and at a point nearly-solid, thus conducting energy for the fan to turn. When the engine is cooled down the liquid’s viscosity comes down pretty low and the fan doesn’t get any energy from the engine, but merely moves on the wind coming thought the radiator.

My problem is, why did it start becoming an issue now? Cos when the car was test driven it didn’t show this problem.

First we thought it might be because the AC compressor might be straining the Engine to a greater lever with the newly added gas, but after the over-heating incident we didn’t turn the AC on, and didn’t run the car a lot to check for over-heating.

Most websites sat it cant be repaired and that the pump/clutch will have to be replaced? What do you guys think?

[fuzzo]

welcome to the wonderful world of bimmers... my old car had a similar issue. the car kept over heating for various reasons. bad radiatior/fan. hose leaks etc.

start from the basics and try to find the problem. i gave up half way and sold the car. the guy who took it after me spend about 200K to sort the car back to running condition.

also how long was your test drive? any highway time?

[Watchman]

welcome to the wonderful world of bimmers... my old car had a similar issue. the car kept over heating for various reasons. bad radiatior/fan. hose leaks etc.

start from the basics and try to find the problem. i gave up half way and sold the car. the guy who took it after me spend about 200K to sort the car back to running condition.

also how long was your test drive? any highway time?

well, the test-tun was not very long and not a lot on the highway....

today we drove down to Coronado, and we were pretty much on the highway most of the time.. and with the AC on the temp was about 1/4 of the range.. when we hit the city it got back up to about 1/2 and would have kept rising but we got to a highway again and again it droped down to 1/4. The thing is, as i've heard and read on the net BMWs work on a slightly higher temp... and they reach thier working tempreature (normally about little under 1/2 of the range) pretty fast.. And my uncle's other BMW (540i-yom1995) reaches it in a few minutes and never goes over or under, no matter what the road...

So, we probably might replace the fan-clutch, depending on the cost...

MADMAX, any comments?

[madmax]

well, the test-tun was not very long and not a lot on the highway....

today we drove down to Coronado, and we were pretty much on the highway most of the time.. and with the AC on the temp was about 1/4 of the range.. when we hit the city it got back up to about 1/2 and would have kept rising but we got to a highway again and again it droped down to 1/4. The thing is, as i've heard and read on the net BMWs work on a slightly higher temp... and they reach thier working tempreature (normally about little under 1/2 of the range) pretty fast.. And my uncle's other BMW (540i-yom1995) reaches it in a few minutes and never goes over or under, no matter what the road...

So, we probably might replace the fan-clutch, depending on the cost...

MADMAX, any comments?

I've heard that the fan gives trouble in the 320D also. A replacement cost about Rs.50K, I've had no direct experience with in this kinda issue...

[Duncan]

As much as European (esp German) cars are my firm favourites in performance and balance, they can be a b***h as they age.

Your problem could be due to several reasons. Could even be a problem that just surfaced and had nothing to do with the A/C.

However, if I were you, I would get a second opinion on the A/C and the cooling problem from another reputed garage. Also remember, not all expert garages that predominatly work on Japanese cars can be good when it comes to German makes.

Hope this helps and keep us posted.

Cheers

[Devinda_Z]

had é same issue on é Landy - simple solution was to forget bt é clutch on é fan and bolt it solid so that it operates right throught as é engine works as opposed to firing up when é eninge temp rises...

its slightly inefficient set up but it far out weighs é cost of replacement of é viscous fan unit!

[dhp]

Hey! atleast be glad its not one of the "exploding" fans like I've got under the hood. I'm not sure of your location, but there are many companies that make electric replacement drop-ins for the OEM. I can proly suggest a few places if you're in the US.

I have been putting off mine for a while and now I need tires...so I'll be putting off the cooling sys replacement even further. The e39/46 cooling fans are made from a polypropylene material that simply disintegrates due to being exposed to heat under the centrifugal force. Unfortunately when it does, it destroys the inside of the hood and sometimes takes out a bunch of peripheral hoses, wires etc. If the hood is open, it can seriously hurt or even kill you. Like someone said, welcome to the world of bimmers

[Devinda_Z]

.....& i thought Land Rover quirks were bad!!