Landseer

I have a couple of these fans that are spinning too freely when hot, so that the clutch is slipping in stop/go or slow traffic, hence not putting enough air through the radiator. (The 84,85 and 86 clutches are identical parts BTW.)

I'm not ready yet to spring for replacing them with electric fans.

Anybody here having success with refills?

I've ordered one dose of Toyota Landcruiser (thickest of three choices) silcone fluid and expect it to arrive next week.

Am wondering if anybody has found a replacement or has ideas on some sort of repair/patch for the little rubber plug that supports & seals the pin under the front metallic strip?

I've searched and read. Anymore practical tips from recent attempts?

PorKen

I haven't refilled any myself, but I remember reading about a different source for the fluid, with lots of grades - silicone rc-car differential fluid - on a Mercedes forum:


example

linderpat

I didn't think these were refillable? How do you do it?

Landseer

Here are the basics.

http://www.nichols.nu/tip482.htm


Thanks for that reference, Ken.

Any other tips would be appreciated.

76FJ55

I refilled mine last summer, and it seem to be performing well since. There was a noticeable decrease in engine temp in low speed conditions. As far as I can tell I haven't lost any of the fluid I put in and I reused the original rubber seal.

linderpat, here is a link to one of the write-ups on refilling.
928 fan refill

toofast928

Consider a 14" electric fan.

leperboy

This is what I used too. I bought it at a local hobby shop for about $3. What I don't know about the R/C car silicone oil is how well it stands up to heat.

My problem was that once I removed the bimetallic strip to open up the fan to insert the oil, it never sealed well again and I lost the oil. I had to buy a used viscous, installed new bearings and haven't had any problems. I don't know of any solution for making the pin seal to the rubber disc seal.

When putting oil in the fan, have a heat gun or blowdryer to heat the fan up while you spin it. You can get a lot more oil in that way.

Matt

Mrmerlin

to finish this job you need to take out the bronze pin and put it into a piece of rubber hose or the tip of an air gun nozzle then with a piece of 600 grit gently polish the shaft to remove any gouges this should reseal the pin to the green seal on the front of the fan, if OTOH the gouges are too deep you might take a look at one of the other fans to find a good pin.
I used Toyota fluid in my fan and it has worked as advertised and no leaks , i did have to swap out the pin as the original was gouged

ROG100

I seem to remember that the 10,000 weight was the heaviest from Toyota.
On the site Ken refered to they have 50,000 weight - would that be better or to thick???

IcemanG17

thats what I did on the 928 estate.....that with the AC fan seems to work well enough, even under racing conditions...plus the 1800cfm electric 14" fan was only $41 on my door!

76FJ55

the 14" may be sufficient, but racing and street conditions are very different. I understand that in racing you are under a high load more frequently than on the street but it seems to me that you will pretty much always have good airflow due to the speeds you are traveling. when the VC is going on a street car there usually isn't an issue when moving, the issues arise in stop and go traffic when the is little relative wind. I am not saying it may not be a good option. I just don't know if the Estate is a good application to use as a comparison.

Has anyone installed a 14" and used it for street? How has it been working?

IcemanG17

I have found that the stock pusher fan actually works pretty well.... Intially when we raced the Estate it was the ONLY fan..& it wasn't set right against the radiator, so air was spilling out the side..but the car ran fine for the 1st race WITH a backwards thermostat....in our next race it did overheat, but once the thermostat was fixed it was better....only overheating when the pusher AC fan was OFF....

I tried running only the 1800CFM puller and took the pusher out.... on track it was fine....as soon as I came in the pits the temp spiked...it would have overheated, but I shut it down..... Once I put the pusher back in....I could come in the pits with no problems....

Given that the pusher is rated at 1200CFM and pushing isn't as efficent at pulling air....I would say one of the dual fan setups with nearly 3000cfm is plenty....that with the AC pusher will be enough for any 928....

PorKen

I don't think 16V cars have enough alternator to support dual fans?

I've been using just the A/C fan for a while on my '85. It doesn't have A/C, though. I have a dual 11" SPAL to go in.

I'm keeping the clutch fan on my '86.5, as it works the best for A/C.

Chris Hansen

I just replaced my fan clutch and bearings with new, and the car runs much cooler in stop and go summer weather. Found one for about $320 new with a little shopping.

Landseer

Good discussion, sounds like I'm on the right path focusing on the fan clutch.
Will polish the litte pin. If lucky, it will reseal, will post pictures.
Will use some heat to assist fill.

I'll try to match the bearings at NAPA this week. (probably be more expensive than porsche). Good idea, two feel rough.

Then try to find some more silicon fluid at an R/C car seller. It is $18 per container at toyota. I think I need two, but bought only 1.

When the 86 car is hot, and I turn it off, the fan stops quickly.
When the 85 car is hot, the fan free-wheels many rotations when the engine is stopped.
The 84 clutch on the 85 car also free-wheels --- from what I read in archives, that may mean both need refill.
More to follow.

Also, the 85 car has the 319 option due to 32V, no spoiler. It has a somewhat smaller diameter drive pulley for the fan.

I got some grit out of the 85 radiator doing a reverse flush, also removed an ancient radar detector sensor that was blocking about 24 square inches of radiator. Those two moves have stabilized the needle at horizontal when the car is running 40mph or more. Infrared is showing just about the same delta T across the radiator as the 86 car. 85 car temp climbs when idling in driveway, 86 car stays rocksolid steady.

Ambient hasn't gotten much above the low 80s yet here.


Related topic, here's a picture of a DIY radiator flush. I put about a bunch of cascade soap and cold water (no hot source) thru the radiator backwards, then put about 80 gallons backwards and forwards through it to rinse. (first picture is forward rinse, second is reverse flush) Got some grit on each shopvac full.