Fourtrak Fan turning


I have a V reg Fourtrak TDS (72000 miles). I thought the temp guage had gone last week as it stayed down at the cold end. But then we quickly noticed we had no heater either. Turns out the fan is turning full time and over-cooling everything.
Local garage had a look at it but can't fix it. Fan turns freely by hand but there is just enough (viscous??) resistance for it to start turning whenever the engine switches on. What is the remedy - replace fan ??




Hi Alistair,
It's more likely to be your thermostat that is opening at too low a temperature . If your thermostat is working correctly then it will only open when the engine temperature is hot enough, so the gauge would show hot and the heater would be getting hot water. The fan will only be cooling the water that is in the radiator. It's also much easier and cheaper to try the thermostat first ( and if that doesn't cure it then it has only cost you a thermostat. If you try the viscous fan first and it doesn't cure it, it's a lot of money for nothing)

Hope this helps


Thanks for the reply.

The thermostat has been nominated for replacement and local garage have one on order so maybe that is the problem.

I assumed at start up everything was cold so the fan ought to be at a standstill from the outset and only switch on as things overheated. Since the fan runs instantly the engine starts, even when overnight stone cold, I assumed it was a fan fault.

Hopefully thermostat is problem. Meanwhile poly bag down the front of radiator is puttin temp. at mid range on the gauge.

Incidentally, reading other posts on this forum, I also have vibration in 5th gear at around 1900 revs. Had it for a couple of years. It was suggested that I had put prop shaft back on out of balance after D-I-Y UJ replacement Also suggested I needed a full back end renovation. I have just tried to ignore it till something serious happens. Pleased to note it might just be a Daihatsu thing and not too serious.

Thanks for the forum.



Hi Alistair,

Did the vibration appear right after doing the UJ replacement? Did you split the propshaft at the sliding joint when you did the job? If the prop was split then you have to make sure that it is aligned properly when you put it back together as a misaligned prop will give you vibrations. The 'yokes' (the holes that the UJ caps fit into) at either end of the propshaft tube must line up. Most props have a master spline on the sliding joint so that you can't easily push them together but they aren't always easy to see and it has been known for people to use excessive force (a big hammer) to persuade the prop back together. Its easy enough to see if you get on your back and have a look both ends of the prop.

It could also be as simple as a tyre out of balance but as you've had the problem for a couple of years you've probably change the rear tyres during that time anyway, but still may be worth getting them checked

I hope i've explained that clearly enough and hope it helps, Daz

Fourtrak fan

Thanks everybody for taking the time to offer advice.

A mechanic set me straight at the weekend about the fan always turning a bit so I now understand that its not likely to be a fan problem. Still waiting on new thermostat to arrive and hope that it will turn out to be that simple to fix. Need the heater up here in Central Scotland. Smile

Re propshaft - excellent tip about the jubilee clip. Sounds the type of repair I would go for as a permanent fix.

Vibration really only noticable in 5th gear at 1900 revs (45mph??) Either side of that is fine and it doesn't really bother me.

Big fear was experience with previous Fourtrak J reg. Vibration started in 5th gear after about 70000 miles and got worse and worse. Eventually had to do gearbox strip down and rebuild for not unreasonable £1000.

gearbox was full of water and fifth gear had badly worn away.

Suggestion was that I ploughed through puddles on the farm road and over the years the splashes hit the underside of the body and trickled down the gearstick into the gearbox where it turned into a pretty inefficient oily emulsion. Hence the problem.

I was worried vibrations was history repeating itself but it has not got any worse over the past two year. However it easy to crawl under the Daihatsu and take a look at it agin.

Thanks to everybody for the help.


Rad & Prop.

1. Change your thermostat. Its stuck in the 'open position'.
2. You have probably reconnected the pro-shaft in a different position from its origional set-up. Always mark the shafts and then match the marks when re-fitting.
Tip ...... use a big jubilee clip [hose clip], open it out and fix it around the prop shaft. By testing and changing the position of the jubilee clip any prop-shaft vibration can be minimised. [It act like balance weights for balancing the wheels.]

Have a look at the linked pag

Have a look at the linked page. It's a post about overheating, but I think my description of cheacking the fan for 'free wheeling' should be pertinant to you. The fan is not stationary when not 'working' it's just not physicaly yanking the air through the rad.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.