coupling fan refill oil silicone

chris lc90

Active Member
Aug 18, 2010
88
0
16
greece athens
the last month i stopped to here one spesific noise from the fan ,when start the engine
also a lot of mud was concentrated to the radiator.i dismantled and wash it.also change the fluid and the thermostat.has 170.000km
but what happened with the fan? the book said to check visually for leakage or if have damage the bimetal spring forward..and one of these reasons happens to change it with a brand new..i opened and add oil silicone (this provided from toyota and costs 6,5 euro)and the problem stopped

http://www.youtube.com/watch?v=3ACx7GTCn7Y
 
Don't like the adverts? Remove them by becoming a supporting member.   Click here

knicko

New Member
Dec 23, 2012
48
17
18
Redruth, Cornwall
Did an overhaul of my fan clutch unit yesterday (also changed all belts, water pump, radiator and put in a 76 degree thermostat - not had any problems but with 133k miles on clock wanted to do some precautionary work). On test drive today, the vehicle comes up to temperature nicely and no signs of leaks or overheating (I know the stock temp gauge isn't to be trusted but drove for many miles so expect any serious cooling problems would be self evident).

My issue is that once the vehicle comes up to temperature (I was driving on B roads, villages, etc), there is a loud 'wooshing' noise on acceleration which I'm pretty sure is the viscous fan kicking in. Never heard it before I did the overhaul. The truck wasn't really working hard and I wouldn't have expected to hear the viscous fan working, or at least not all the time. Outside temp (on the in-car display) was 19C.
Is it possible that I have over-filled the silicon oil? Having watched the above You Tube video, I reckon I have put in more oil than the guy in the video - I used about 50ml of 10000 cst silicon oil. I filled the clutch assembly until oil was overflowing from the four holes on the face of the plate. There didn't seem to be much oil in the unit when I took it apart. I checked the bi-metallic strip and this was able to rotate by about 30 degrees.

I have heard/read many comments about these fans failing to come into action, leading to overheating problems, but I seem to have the opposite problem.

Any ideas please?
 

Shayne

Well-Known Member
Guru
Feb 2, 2013
13,367
5,051
113
South Wales UK
Problem is there are no official figures to work to . I have read loads on this subject and settled on 60ml of 1000cst is what i will do if i ever get around to it . As far as i can tell no benefit can come from the fan working too well but on the flip side it does no harm other than minor power loss . It would annoy me so i would remove some oil .
 

clivehorridge

Well-Known Member
Guru
I am in romania
May 23, 2012
14,861
4,854
113
Comarnic, Romania
Garage
Problem is there are no official figures to work to . I have read loads on this subject and settled on 60ml of 1000cst is what i will do if i ever get around to it . As far as i can tell no benefit can come from the fan working too well but on the flip side it does no harm other than minor power loss . It would annoy me so i would remove some oil .
I'm with Shayne on this, at great expense, I fitted a new viscous fan unit when mine failed about 5 years ago (at that time I wasn't aware that they were serviceable) :icon-cry:

Since then, it's kicked in when needed, which is rare, steep climb, heavy mud conditions, 30C degrees outside temps, low speed work, all the ingredients for a boil-up.

IMO, either learn to live with it, or remove some oil. Over time, you'll probably find it will kick in later as the excess oil dissipates, but as Shayne mentioned, it's a bit 'suck-it-and-see'.
 
Last edited:

knicko

New Member
Dec 23, 2012
48
17
18
Redruth, Cornwall
Thanks for your replies. Having also done a bit more searching on this and 'the other' forum, I have an idea that I might have upset the balance of the fans operation by refilling with 10000 cst oil. It seems the original units used 3500-4000 grade, although some have replaced theirs with 8000, which makes the fan come on earlier and stay on longer.
By using 10000, I reckon I have gone a bit too far with the viscosity, causing the problem I have now got.
The truck sounds like a 747 every time you touch the throttle (once warmed up) and I can't really live with that. I've just ordered some 5000 cst oil and I will drain and replace to see if that solves it.
 

Shayne

Well-Known Member
Guru
Feb 2, 2013
13,367
5,051
113
South Wales UK
Personally i don't think the viscosity will make much difference i think of it as candle wax which melts to engage so if there is too much in there ......
 

froggy Steve

Well-Known Member
Supporter
I am in europe
Jul 26, 2012
2,722
576
113
Dordogne, SW France
I have too much cst 10,000 in mine and fans on most if not all of the time. I have also seen (aftermarket temp guage) over 100 degrees on one occasion, even with fan on! I have since had the rad changed and put an extra rad on for the auto box, and its dropped the average running temp to 78-80 dgrees and hard climb in heat to 94 or so, so very happy indeed with the results. I can now sleep at night....mostly....ball joints.........eeek
 

knicko

New Member
Dec 23, 2012
48
17
18
Redruth, Cornwall
Ok thanks for all the replies and suggestions. I've now also ordered some 7000 cst oil (so I will have tubes of 5000, 7000 and 10000 weight).

I will dismantle and try different options to find the one that suits my truck use - 'suck it and see' as Clive said earlier!

Many thanks,

Nick
 

knicko

New Member
Dec 23, 2012
48
17
18
Redruth, Cornwall
Yup....that's sorted it.

Dismantled and drained the fan unit. Refilled (not overfilled this time) with 7000 cst and no more 'hyper' fan, except on a long drag up a steep hill today.

Thanks for your ideas everyone.
 
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock    No Thanks