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T25 OVER HEAT AND FAN
Posted: 08 Feb 2010, 09:25
by VERAT25
hi .
can anyone help with knowledge of this problem.
re temp gauge and red light flashing.
1st run out this year and i have a prob with red light flashing below temp gauge.
coolant is ok/expansion tank full/and res is full ..no leaks on system.??
have bled radiator.....but seems that fan is not coming in(fuse is ok)
could this be temp sensor on rad or thermostat?????.
temp gauge gets to 3/4 very quickly???
thanks
verat25(cardiff)
1.9 watercooled
Re: T25 OVER HEAT AND FAN
Posted: 08 Feb 2010, 11:11
by Red Westie
Usually caused by a faulty thermo switch on the radiator (it looks like you have covered other possible causes) simple screw out screw in (coolant cold)
It is possible to bridge certain contacts to this switch to bring on the fan (at least this eliminates wiring or motor failure) although I'm not sure which contacts as most are two speed fans sooo..someone?
Martin
Re: T25 OVER HEAT AND FAN
Posted: 08 Feb 2010, 12:40
by tetleysid
I've had the same problem

I wired in a seperate switch to operate the fan manually by bypassing the thermo switch and all was well for a while then one day last summer I noticed my temp. creeping up in a traffic jam so put on the fan and all I got was a buzz

thats a problem for future sorting
Re: T25 OVER HEAT AND FAN
Posted: 08 Feb 2010, 21:04
by colinthefox
In the plug thingy with the wires coming out that goes on the rad switch there are three terminals.That gives you three possibilities for linking them out with a short piece of wire. One pair does nothing, one pair brings on low speed fan, and the third pair brings on high speed fan. Thermoswitches fail constantly.Fit a new one anyway, carry a spare.
Re: T25 OVER HEAT AND FAN
Posted: 09 Feb 2010, 07:27
by VERAT25
thanks for the help guys.
day off today so will do tests later and let ou know
cheers
verat25(cardiff)

Re: T25 OVER HEAT AND FAN
Posted: 10 Feb 2010, 13:17
by VERAT25
hi there again.
re my earlier question.
fan works ok-(on both speeds) when i use a test wire across terminals.
red light under needle for temp still flashing???
would this be a faulty level sensor on expansion tank.
any comments appreciated
thanks
verat25(cardiff)

Re: T25 OVER HEAT AND FAN
Posted: 10 Aug 2010, 19:23
by tetleysid
tetleysid wrote:I've had the same problem

I wired in a seperate switch to operate the fan manually by bypassing the thermo switch and all was well for a while then one day last summer I noticed my temp. creeping up in a traffic jam so put on the fan and all I got was a buzz

thats a problem for future sorting
The problem was the multipoint earth point under the dash, I realised this when several electrical items started to fail together so I presumed a break in the curcuit and as they all shared a common earth i deduced that that was the culprit, sound like Sherlock Holmes eh?
