Problem with fan clutch.

[Stefano_b]

I found out that my old fan clutch, that I have made rebuilded a couple of years ago, doesnt work good: at every temperature the clutch locks the fan! I think problem is that when technician rebuilded it, he didnt respected the correct sizes (maybe because of a larger glue thickness?).
Any hint? Anyone has another fan clutch for sale? Maybe machining a little the clutch material could work?

 

[Stevehose]

I would upgrade to the 9 blade fan and viscous clutch and not worry about that anymore

 

[Stefano_b]

Hello Steve,
When I bought this car I bought a used 9 blade fan with viscous clutch as well, and gave them to the shop that was doing some works.
Unfortunately, when car was ready, they told me that 9 blade fan had no room enough to fit! I have to check if I gave them also updated water pump because I do not remember.
At Wallothnesch told me that I should have changed also radiator , but a dear friend in this forum told this is not a mandatory task!
Now, because I do not want to disassemble all in vain, my question is: there is a chance to measure the clearance between five blade fan and radiator to be sure there is room enough for the new set? It seems to me that my radiator and fan are very very close one eachother (see photo).

And which should be exactly the needed parts to perform this task?
Thank you
Stefano

 

[Stevehose]

@HB Chris may know which of the 2 upgrade options has the shortest protrusion into the radiator.

 

[Stefano_b]

@HB Chris may know which of the 2 upgrade options has the shortest protrusion into the radiator.

Thank you Steve, this could let me save time and money!

 

[tochi]

I found out that my old fan clutch, that I have made rebuilded a couple of years ago, doesnt work good: at every temperature the clutch locks the fan! I think problem is that when technician rebuilded it, he didnt respected the correct sizes (maybe because of a larger glue thickness?).
Any hint? Anyone has another fan clutch for sale? Maybe machining a little the clutch material could work?

Hello Steve,
When I bought this car I bought a used 9 blade fan with viscous clutch as well, and gave them to the shop that was doing some works.
Unfortunately, when car was ready, they told me that 9 blade fan had no room enough to fit! I have to check if I gave them also updated water pump because I do not remember.
At Wallothnesch told me that I should have changed also radiator , but a dear friend in this forum told this is not a mandatory task!
Now, because I do not want to disassemble all in vain, my question is: there is a chance to measure the clearance between five blade fan and radiator to be sure there is room enough for the new set? It seems to me that my radiator and fan are very very close one eachother (see photo).

And which should be exactly the needed parts to perform this task?
Thank you
Stefano

Regarding your first post, it seems that you answered your own question. The old-style fan clutch operates like a drum brake. You apparently had the clutch “shoe” relined with new friction material. Just like a drum brake, relined shoes can be machined to fit the drum, although unlike drum brakes your fan clutch does not, to the best of my knowledge, have any obvious means of adjustment. Bear in mind that the metal drum onto which the friction material is applied may also be grooved, possibly contributing to your “sticky” or “snug-fitting” fan clutch. Either way, given your current predicament, it seems that you have little to lose by removing small amounts of friction material and I would imagine that this could easily be performed with sand paper. Another thought is to accelerate the fan clutch wear by preventing the fan from turning with the engine running or simply leave things to wear normally. (I can think of other means of abrading the friction material, but will leave this to you or your mechanic’s imagination.) Note that if you remove too much material your clutch will likely "free wheel" and not function properly, so trial and error might be your best bet.

Upgrading to a nine-blade fan is good advice, but as with the case of many available upgrades, it may not be necessary, unless your car is prone to running hot or overheating. The same thought applies to upgrading radiators. In other words, if the current radiator is clean and leak free, it may be adequate for your engine’s cooling needs. You seem to be aware that not all cooling fans are interchangeable so that an upgraded nine-blade cooling fan requires a slightly different pump than the pump mated to a five-blade fan. The difference is how each fan and the integral fan clutch attaches to the pump. This means removing your current fan clutch assembly along with the pump.

Your related question regarding clearance between the cooling fan and the radiator is difficult to judge from afar. The image you posted looks normal to my eyes. However, the fact that the clearance between the fan and the top of the radiator seems adequate does not guaranty that there is sufficient clearance on the lower area not shown in your photo. Be aware that clearance is normally very tight (~15mm) so that you should make sure that your motor mounts and transmission mount are in decent shape in order to prevent significant forward engine travel and have a fan that kisses the radiator.

 

[Stefano_b]

Thanks Tochi for the valuable advices and for the time you have dedicated to me. I think first to try to wear out the friction material until the clutch can be inserted effortlessly. The engine mounts are new and that's a good thing. It would be very useful to know the exact dimensions of the water pump + 9-blades fan assemblies in order to verify the possibility of upgrading in the future, if necessary. The radiator was completely restored, but Wallothnesch told me a thinner type (?) is needed with the new fans.

 

[tochi]

I now see where this topic was discussed some time ago, but maybe did not provide all the answers for you. https://e9coupe.com/forum/threads/fan-not-properly-cooling.24332/.

I am no expert, but from personal experience with a few fan upgrades, clearance between the upgraded fan and stock "original" radiator has been reduced, but not enough to pose a significant problem. E9 body integrity was never the best, so that after the passage of many decades, what began as "relatively" identical E9s can end up dimensionally different. And as is often said: "your mileage may vary." Thus, what works for one car may not automatically work for all similar models and working clearances can differ. Keep in mind that fan-radiator clearance problems can be addressed from both sides. Certainly a thinner radiator may be one answer, but occasionally, additional clearance can be gained with the stock radiator by modifying existing mounting points or "massaging" the attaching bodywork. https://e9coupe.com/forum/threads/e3-fan-and-radiator-spacing.35925/ Another obvious alternative is "electric."

Eight blade fan

 

[Stefano_b]

Thank you, plenty of infos acquired, and a lot to deal with!