Viscous Fan Coupling - How To Test ??
Submitted: Monday, Jan 01, 2007 at 21:54
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Beast of Bodmin
Hi guys & Happy New Year to you all,
I've been nursing the cooling system along on the 4.5 auto 80 yota, but l want to iron out the symptoms so l repair only as needed.
On v.high temp days, crawling along in traffic, the temp starts to climb towards the red. Other days and/or not crawling along, it remains
rock solid at about half gauge level.
I know the header tank has a slight leak along the crimped joint. The apparently it's not repairable as the rad is old - New Rad = $$$$ great start to N.Yr.
But is the viscous fan drive faulty too??
A mate reckons that when the parts are new, you can grab the input and ouput shafts of the viscous unit and as they are turned against each other (a lot!) the 'coupling' between them stiffens up. Thus on an old part, if it doesn't stiffen or is solid/seized - it's no good.
It was also said that you should be able to stop the fan (at idle) with a folded bit of cardboard but as revs are increased, the fan will 'couple' and drive 100%. However a US website says if you can stop it at idle, its buggered anyhow. Confusing, contradictory advice!
As
mine is in the car, l cant try the 1st idea. However the fan is driving and wont stop with a bit of cardboard - it's not seized either. What does that mean?
Another sympton mentioned to me is that a lazy viscous coupling will affect the a/c ability to cool the car. My old R12 system is now filled with R143a (plus new drier) and doesn't cool as
well as it used to either, thus swaying me toward thinking that the viscous coupling may be lazy.
Any other ideas on how to
test this would be appreciated.
Cheers
BoB
Reply By: Member - DOZER- Tuesday, Jan 02, 2007 at 07:52
Tuesday, Jan 02, 2007 at 07:52
To
check fan
....start motor. listen to fan noise,note revs... note it quietens down after 30 seconds or so. Drive till normal op temp...cover the grill side of rad with cardboard from the old case you have in the recycling....turb up fast idle to 1000 rpm again (like it was when started cold) watch temp gauge...if fan working correctly, a little past half way, the fan will kick back in and you will hear it do so.
To
check fan no2 (this is what a friend did)
Install electric fan up front from old commodore....next time it gets hot, turn on fan, notice your nose now has ice forming on it....and engine temp has dropped back to normal.
Change viscous, and leave other there aswell for turbo boosted air conditioning.
Andrew
AnswerID:
212819
Reply By: Chucky - Tuesday, Jan 02, 2007 at 10:13
Tuesday, Jan 02, 2007 at 10:13
You can refill the viscus fluid in the fan clutch.
Only takes about 30ml. You can buy tubes of the stuff from toyota for about $15 each. I replaced all the fluid when I did
mine and it used just under 3 tubes.
A really good DIY tech sheet is available at outerlimits4x4.com
I just follwed this and it only took me a couple of hours and everything was good afterwards.
I had to replace my water pump and when I went to get my rad, stripped and cleaned was told it was stuffed, so I decieded to replace the thermostat at the same time. The bloody thing was still getting hot towing my camper. Was told to top up the fluid inthe hub and it has never even looked like getting hot since. Have since crossed the simpson towing a O/R camper and done all sorts of things since with out a problem.
AnswerID:
212830
Reply By: Philbee - Wednesday, Jan 03, 2007 at 22:42
Wednesday, Jan 03, 2007 at 22:42
ok temp rising crawling along or stopped in traffic would indicate the viscous hub not operating correctly but if the radiator has a leak at the header to tank seal, you would have pressure loss and also result in higher than normal coolant temp. yeah is expensive to replace the radiator but is repairable, (top tank part number TOY9244PT, O'ring P/N OR744X69R and Grip Plate P/N: GP744X69
Dont stick things in the fan to try and stop it, its dangerous and could also damage fan blades, when hot and idling you should be able to feel it pumping hot air towards the engine ( it sucks cold air from the front). and yes is cheaper to rejuvenate it than replace, the silicon oil from Toyota ( Part Number 08816-10001) is available in 18ml tubes, you need around 3 tubes to do a cruiser, just becarefull with the o'ring it's not available and in most cases when you take it out it stretches and wont go back.
As for your A/C, R134A is around 20% less efficient than r12, if your cooling system is working correctly you may find it 1 or 2 degrees cooler, but mostly the difference is on start up, R12 cools almost immediate while R134A takes few minutes.
Phil...
AnswerID:
213114