A question for those with more knowledge

[Maverick]

A friend a work who has just sold his Surf was informed by veiwers that some Surfs viscous fans stop working when the vehicle reaches a certain speed, which is one cause of the engine overheating. The way to tell is to look at the shaft, and if it is blue a modification has not been caried out to rectify this.

Is this true or was this just a case of making an excuse to reduce the price.

[marky]

A friend a work who has just sold his Surf was informed by veiwers that some Surfs viscous fans stop working when the vehicle reaches a certain speed, which is one cause of the engine overheating. The way to tell is to look at the shaft, and if it is blue a modification has not been caried out to rectify this.

Is this true or was this just a case of making an excuse to reduce the price.

No known info on that one mate, just use the search button & look under viscous fan for further info. just a case of making an excuse to reduce the price is probably the case

[NiftyNev]

I remember reading some info on recalls and there was mention of some Surfs (can't remember what models) being recalled for a faulty shaft on the water pumps.The link I have for this info is not working at the moment so I can't check.Will let you know if I can find anything.

Neville

[Maverick]

This appeared on my email last night from Tony N, but for some strange reason didn't appear on the forum.

"The idea is right, but it has nothing to do with overheating.

The viscous coupling drives the fan when engine is reving slowly, which is generally when you are going slow. As road speed increases, air flow though the rad increases and you don't need the fan to be working. Letting the fan slip at higher RPM increases power and MPG as the engine doesnt have to drive the fan. Generally you don't park up and let the engine run at 3000rpm so there is no point in dribving the fan at high engine revs.

IF you have a problem with the viscous coupling, then the fan will slip at low revs there for at low road speeds, when air flow though the rad isn't enough without the fan running properly and you might have problems.

"

[kevb]

the type of fan on a 2lt surf is an air sensing fan which means its torque limiting which is what you where talking about in last post but it also has a spiral shaped bimetal sensor at the front of it which senses the temperature of the air coming from the radiator and it either covers/uncovers a port that stops/starts the flow of fluid from the resevoir to the drive chamber which disengages/engages the fan.it gives more power saving than a torque limiting fan and a direct drive belt fan.

[TonyN]

I typed and then realised you wern't just talking about how a viscous fan works, so deleted it cos it wasn't what the question was about.

This appeared on my email last night from Tony N, but for some strange reason didn't appear on the forum.

"The idea is right, but it has nothing to do with overheating.

The viscous coupling drives the fan when engine is reving slowly, which is generally when you are going slow. As road speed increases, air flow though the rad increases and you don't need the fan to be working. Letting the fan slip at higher RPM increases power and MPG as the engine doesnt have to drive the fan. Generally you don't park up and let the engine run at 3000rpm so there is no point in dribving the fan at high engine revs.

IF you have a problem with the viscous coupling, then the fan will slip at low revs there for at low road speeds, when air flow though the rad isn't enough without the fan running properly and you might have problems.

"

[NiftyNev]

Here is the link on recalls - http://www.showmesome.info/hilux/info/recall.htm

This is the part about the Fan Coupling/Water Pump.

Fan Coupling/Water Pump

Frame numbers: S-LN85, LN85-0006524 - LN85-0030101
Report Date: June 26 1990
Production period: March 17th 1989 - April 16 1990
Condition circumstances: Because the water pump shaft for cooling which is installed in the Diesel engine (the water pump axis) with the fan coupling which is been connected (the fan joint) structure of the bearing is inadequate, resonating due to the vibration of the gin, excessive load falls on the particular shaft, when use is continued in this way state, when it is worst, the shaft breaks and the water pump does not operate, overheats and is a possibility of becoming travelling impossible.
Fix: All vehicle, the fan coupling and the water pump are exchanged to the item well.

Neville

[da SLUG man]

Here is the link on recalls - http://www.showmesome.info/hilux/info/recall.htm

This is the part about the Fan Coupling/Water Pump.

Fan Coupling/Water Pump

Frame numbers: S-LN85, LN85-0006524 - LN85-0030101
Report Date: June 26 1990
Production period: March 17th 1989 - April 16 1990
Condition circumstances: Because the water pump shaft for cooling which is installed in the Diesel engine (the water pump axis) with the fan coupling which is been connected (the fan joint) structure of the bearing is inadequate, resonating due to the vibration of the gin, excessive load falls on the particular shaft, when use is continued in this way state, when it is worst, the shaft breaks and the water pump does not operate, overheats and is a possibility of becoming travelling impossible.
Fix: All vehicle, the fan coupling and the water pump are exchanged to the item well.

Neville

another quality translation... have a few beers and it will make perfect sense!