Imo000

If it leaked out once, it will again. Keep an eye on it.

928man

What do you have to do to refill the fan clutch, does the fan and clutch assembly need to be taken off and disassembled? I see new fan clutches for sale but are $500-600 . My car overheats if left to idle long but is ok at speed. What oil is used and why is a heat gun needed?

Podguy

Bill,

There should be an explanation on renn list or the net. Basically you remove the fan. This is easy just remove the top fan shroud and then the three bolts on the fan support. If you are working on a later car then you have to remove the throttle bracket too. No need to release the fan belt as it will just slip off and can be put back together by just bolting the bracket back on. Off about 10 minutes.

The fan works with a bi metal strip that puts pressure on an internal valve. As the temperature increases the bi metal strip bends and opens the valve allowing more fluid contact within the clutch. The fan should always be kept in a vertical position. Oil can leak out over time - I suspect from being positioned wrong when off the car, but that could be supposition.

Toyota sells small bottles of the oil. There are different numbers so you want to find out the right one. The agency can get you the oil cheap and quickly. I found mine took about one and a half bottles.

The bi-metal strip is held in place with some RTV. Cut this away with an exacto knife and carefully slide the strip out without bending it. Remove the small valve and then put the oil in the hole. A heat gun can be used to encourage the oil to flow and to open up the inside.

Reinstall the valve and bi metal strip securing it with some new RTV. Be sure to make note of which side of the bi metal strip was facing out - otherwise it will work in the opposite direction and as noted about the oil will then leak out.

I have never seen a fan that will not spin freely - well with some resistance - by hand and I have never seen one that offered resistance after part of a turn. The A/C guy I learned A/C repair from would used a folded newspaper to test fans on Volvos. Not sure what criteria he used to determine if the fan had the right resistance, but he would just force the folded paper into the running fan. Please do not try this at home. It is spectacular to see done and maybe he just sold everyone a new fan clutch, but then he was a pretty honest guy so maybe there was some way of testing resistance that I am not privy to.

Good luck.

jwillman

Note. Not all fans are the same. My 79 did not have RTV holding the bi-metallic strip. It has a cut out tang and slide one direction to clear a hold down tab and then lifts up. Later models have a rubber grommet around the valve plunger, mine did not. I got the silicon oil from a hobby shop. Same stuff used in gas powered RC cars differential and a faction of the cost. Stuff is very thick and heating fan clutch helps move the silicon away from the center to allow faster servicing.

Richter12x2

Especially if it's pinned.

dprantl

Yeah... then it would really be a vicious fan clutch.

Dan
'91 928GT S/C 475hp/460lb.ft

928man

Dan-The Pod Guy- Thanks for the Fan clutch repair info, much appreciated, I don't know if I can get my mechanic to go thru all that but I'll see. I have to solve this high temperature idle problem it has been a problem ever since I got the car. An alternative would be to get the twin electric fans but I've never heard anybody talk about how well they work. Bill

Melo928

I did mine month ago. To get silicon in and stay there, trick is: heat, insert, rotate it like it would fly (all the time). Cool it down, then heat again (rotate) - it will puke some silicon out, stop heating - silicon will be drown back, add more silicon while it cools down.

I did this cycle many times and it swallowd lots of silicon. I think that if you miss that rotation and last heating after inserting oil in, some air will be trapped in and eventually push portion of oil out.

You should also check that bimetal strip really is right side "up". PO's last mech had installed it wrong way in my case. When heating strip, it should bend forward, letting pin move forward and clutch engage - not push pin.

outbackgeorgia

They work well, my S4 has twin puller electric fans, no issues!
Dave

jpitman2

I used a small syringe to help push the silicon in , but my fan threw it all out again quite quickly. Now have dual 11" SPAL fans - bit of work to fab up a mount for them that leaves the top air ducts and looks stock, but for $200 vs $500 for some units, I am a happy camper. Handles 100F + AC fine.
See
http://www.the-fan-man.com/shop/size....html?cPath=33
jp 83 Euro S AT 53k

928man

jpitman2: Thanks for the electric fan info, certainly a lot cheaper than $500 for the made to fit ones.

Podguy

If you watch e-bay close enough sometimes S4 fans go for a reasonable. I am not sure what it takes to adapt them electrically but it should not be much. You will probably lose the hood up feature but they are just 12 volt fans. A relay off the radiator switch should work.

I had a friend who had heating problems until he replaced the fan clutch. A new one fixed the problem.

jwillman

The mercury mystic dual fan set up, fits great and can be picked up at salvage yards for $30 and new for ~$100. I used a Hayden dual fan controller ($42 from Orielly) to turn the fans on seperately. Working great so far.

Landseer

There is a springloaded valve that needs to be pressed with the end of the syringe needle when filling.

I used a basketball filling needle with the end snipped off to that it discharged axially like a syringe (normally they have a side discharge).

They really work well, so before ditching the viscous fan you might at least try filling it.