spinaker

I'm pretty much convinved that my viscous cooling fan clutch on my '85 S is not pulling enough air when hot. At pretty much any speed except idle, temperature remains in the low normal range on the hottest days with the A/C on. Idling in traffic, the temperature runs to the normal max line and turning off the A/C does little to help bring it back down. The viscous fan turns by hand with little resistance when the engine is hot. My electric fan appears to work normally, coming on when hot or when the A/C is on.

I've done a search of past threads on the silicone replacement and my take on the outcome of this proceedure is that it is a very temporary fix with the silicone leaking back out in relatively short order. Has anyone had long term success with this? Has anyone found a way to refurbish the seals which appear to be the culprit?

One thread suggested that there may be a suitable replacement available from a supplier such as Hayden. I note that Hayden does not cross reference a 928 part. Has anyone found a reasonable cost replacement? I'm thinking that if one could be found, this would be as valuable to us a the anchor motor mount swap.

I know that one alternative is to upgrade to the later dual electric setup but I am challenged in the electrical department and could not engineer this on my own. Can anyone guide me on how to approach and execute this upgrade?

Finally, it would seem that if a replacement viscous clutch is my best alternative, then a new one will be the only way to go as a used one could start to leak very quickly.

If you've read this far, you'll probably be glad to hear that I think those are all of my questions.

Many thanks in advance to those who will inevitably jump in with expertise and experince.

H2

I did the silicone fix and have had no problems for 3 years plus. The silicone is expensive though...and there are two viscosities...one better than the other, if I remember correctly. A search of this forum will turn up the proper Toyota product numbers. They'll probably have to order it for you based on the number.

Harvey

spinaker

Thanks Harvey. The fact that you did it on an '85, similar to mine is encouraging.

neilh

FWIW - I tried the Toyota fluid refill on my 81- the fan took almost two bottles ( 18ml in each and around $30 for 2 ) and felt a lot more stiff after filling... 1st time I started it up i would guess most of the fluid was shot out by centrifugal force, as the neoprene or whatever seal on the brass pin (inside the fan) that you remove to fill through was most likely all dried out for lack of fluid, and is either cracked or broken, so the stuff comes right back out.
Neil

spinaker

Thanks Neil. This would seem to be the greatest risk of relying on the refill as a fix. Sure would be nice to find a way to replace the seal. It would make refill the method of choice.

spinaker

A seal?

figgen

Doug

I have performed the fluid injection with the thickest Toyota oil recommended in the other threads. By far the best way to get the oil into the housing is to inject it. You can find a syringe used for mixing oil and gas for 2 stroke engines at Wal-Mart and inject as much oil as the housing will take. After this procedure my fan was noticeably firmer however on hot days at idle I still watch the temp line creep up from the "normal" running temp position but remains lower then the top white line. Like you mentioned your electrics will kick in if you get much hotter than this.

Another thing I have been contemplating is to swap the electric fan trigger switch with a lower temp rated one. Simple swap out and the electrics will kick on sooner.

H2

It took me two expensive bottles too..but I used a syringe to squirt the thick fluid in (wasn't easy), then I used some silicone sealant to make sure it didn't come out. It is tricky..but it worked for me.

Harvey

SMTCapeCod

I filled mine with two bottles-- '83 Euro. It has slowly been seeping and covring my rad hose.

You can replace the whole thing with one aftermarket electric if you choose to -- Dave Robert's 85 Euro is cooled in such a manner. 928Motorsports sells a fan upgrade too.

At one time I paid big bucks for an OEM clutch and its still in my basement.. Problem is, how do I know for sure that IT was never bled out through improper storage?

I'd go electric, but thats just me. You can get an aftermarket switch that works at variable speeds and provides a few seconds of afterun if you so choose too.