3TJ Fan problems and overheating

[Hogdigerdy Dog]

my fan has only ever come on once, i was beginning to think it didn't work, but on the mag run a couple of weeks ago doing 30 up the motorway the gauge went up to about 1/2 way and on it came
Mr yam does do cooling pretty well, i remember taping off 2/3 of the rad in winter on my lc or the thing would never get warm


bit of a long shot but on the coolant front are the coolants compatible and designed for an alloy block and motorcycle specific
some coolants have small (very small) silica beads in em to keep the water system clean but the pump in a bike has much smaller/thiner blades than a car pump and can be damaged with car coolant

edit: if it has 2 types of coolant in it have you actually drained the system completely or just topped up as an air lock would cause your problems

[MarkT]

Thanks for taking time. Yes now I am using Halfords top coolant which is advertised as safe for alloy engines and contains no silicon like their cheaper stuff. I asked Mr evil about this and he said it would be ok. However if there is any doubt I will go back to motorcycle yamaha stuff which is three times the price! I notice that yamaha coolant is now red too.
When I first went down this route I always drained the coolant from bottom hose and reused it but then I thought I could use some fresh stuff so I changed it admitted that didn't flush it that time.

[Hogdigerdy Dog]

the halfrouds stuff is fine, as EC says as long as it's meant for bike's and alloy blokes you'll be ok
i'd still flush the system through as it's the easiest option and something else ruled out

[MarkT]

Thanks for that, I think I will flush it when I fit the fan switch, but as I say I don't know whether to fit stat back in?

[MarkT]

Second thoughts again, think I might stick with my manual fan switch - less to go wrong and very easy to use. I would really like opinions on putting the stat back in?
Thanks

[CMSMJ1]

why not fit the stat?

You are a sensible chap but make a decision based on knowledge and you'll be right.

No stat = a bike that takes ages to warm up which is not a good thing.

Stat in = a bike that gets to temp sooner and then when stat opens all is god with the world.

WHy would you not run the stat?

[Evilchicken0]

Just stating the obvious - does the whole of the rad get warm ??? If there's a cool spot then it could be part of it's blocked.
I'd run the Stat

[MarkT]

Thanks good people, the rad gets hot all over no worrys! It is getting another flushing today and I'll put the stat back in.

[MarkT]

Still not sure about stat, spring looks as if someone's bent it? Tried it on temp test in kettle, it says 82c but didn't seem to open till water was boiling but it did open and close ok. Phoned Fowlers about one: £29 + vat! Anyone have spare would like to change gauge sensor aswell but that is £35 + vat!
The stat is on back order anyway....

[CMSMJ1]

The stat is not your problem.

lack of pressure in your cooling system is the issue.

There are ways and means of getting the system pressure tested - http://www.harborfreight.com/radiator-p ... 65053.html

Something is preventing your bike from efficient cooling..and it is not the stat.