E3 running high at low speed/idle

[Keithry]

My 1970 2800 is running a little high at idle and around frequent stopping low speed streets. It doesn’t run high when I drive on a highway. I opened the vent screw at the thermostat housing and bled the air as much as I could. I ordered a new lower temp rated (original at 80C, this one is 70C) to replace. I see that my asymmetric red 5 fin fam seems to be running alright. I didn’t check whether it’s clutch works or not. Where should I begin troubleshooting on this? Also how does your cars run at low speed?

 

[Stevehose]

Check the fan clutch. Does it spin freely by hand when engine is hot? Alternatively you could stick a rolled up newspaper into the fan while running to see if it stops it.

 

[Keithry]

Check the fan clutch. Does it spin freely by hand when engine is hot? Alternatively you could stick a rolled up newspaper into the fan while running to see if it stops it.

It runs when the engine is on. I can spin it by hand when the engine is off. I can try sticking in a roll of newspaper to see if it stops easily. If that’s the case, does that mean the clutch is not working?

 

[Sean Haas]

correct - here's a thread on shimming the clutch (which I have not done myself yet but intend to) if indeed that's the problem and you want to retain the existing fan ... https://e9coupe.com/forum/threads/overheating.37295/page-3

 

[HB Chris]

I would have the radiator cleaned out by a competent shop. Temps that drop at higher speed are usually blockages.

 

[Stevehose]

correct - here's a thread on shimming the clutch (which I have not done myself yet but intend to) if indeed that's the problem and you want to retain the existing fan ... https://e9coupe.com/forum/threads/overheating.37295/page-3

or from the repair manual:

If a new fan coupling is not available for a repair,
the fan coupling can be blocked for a limited time with two M 6 x 30 mm
screws. The fan then turns continuously.
The screws should be opposite each other to avoid serious unbalance.

 

[Sean Haas]

or from the repair manual:

If a new fan coupling is not available for a repair,
the fan coupling can be blocked for a limited time with two M 6 x 30 mm
screws. The fan then turns continuously.
The screws should be opposite each other to avoid serious unbalance.

That is correct - but when I bought the car despite having re-cored the radiator with an extra row and adding a lower temp thermostat I was paranoid about the cooling since I get stuck in Chicago summer traffic a lot - so after speaking with my mechanics we locked on the fan with the understanding it would be "a bit louder" with the fan running all the time. Well "a bit louder" is more like a freight train at higher speeds, it's really annoying, so in my opinion I would not do that for more than a temporary solution, which is why I was going to go back to the standard bolts and then shim it to make sure it's engaging well and won't slip over time. But as far as solving the problem here HB chris is right to have radiator checked if the fan is not the obvious issue.

 

[Keithry]

That is correct - but when I bought the car despite having re-cored the radiator with an extra row and adding a lower temp thermostat I was paranoid about the cooling since I get stuck in Chicago summer traffic a lot - so after speaking with my mechanics we locked on the fan with the understanding it would be "a bit louder" with the fan running all the time. Well "a bit louder" is more like a freight train at higher speeds, it's really annoying, so in my opinion I would not do that for more than a temporary solution, which is why I was going to go back to the standard bolts and then shim it to make sure it's engaging well and won't slip over time. But as far as solving the problem here HB chris is right to have radiator checked if the fan is not the obvious issue.

Do anyone of you have a picture of how the shimmed fan clutch looks like? I want to get a visual understanding before I try to interpret words into works.

 

[HB Chris]

Steve gave you link, there look at Post 21.

 

[Keithry]

I decided to pursue finding a 2nd-gen 9-blade fan and its clutch. I found this on eBay. Would this fit without having me replace the water pump? Besides what's in the picture, what other part do I need to be able to retrofit this into my current setup with an asymmetric 5-blade fan?

BMW E9 E12 (E24-pre82) E3 M30 8-Blade Genuine RED FAN radiator Kit Clutch Fan | eBay

Find many great new & used options and get the best deals for BMW E9 E12 (E24-pre82) E3 M30 8-Blade Genuine RED FAN radiator Kit Clutch Fan at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[HB Chris]

It will work with the 1st gen water pump as long as there is no large nut on the other side of the fan clutch but you will need the mount for the pump and the large screw both of which are still available I believe.

 

[Keithry]

Thank you all for your knowledge, tips and advices! I got thermostat changed and fan waiting to arrive. Have any of you replaced your radiator to a modern aluminum one? Any tips on finding the right one? This one advertises that it should fit E3 Automatic
https://www.ebay.com/itm/3948897407...-a4ae-ee1c8ae0bfdf|iid:1|vlpname:vlp_homepage

 

[boonies]

I got thermostat changed and fan waiting to arrive. Have any of you replaced your radiator to a modern aluminum one? Any tips on finding the right one?

before installing your thermostat make sure to drill a small hole at the 12 o'clock position to help with bleeding the cooling system.

I did replace my radiator (e9) with an aluminum unit. I was not having overheating issues, but when I removed the radiator while doing other work it was clear that the original unit was failing. No regrets as it eliminates a failure point.

 

[sfdon]

Did you test your fan clutch before you bought the kit on eBay?
what was the result?
you realize you are missing 3 items to attach the new kit to your car- have you sourced them?