Mark w Posted May 18, 2004 Share Posted May 18, 2004 Can anyone tell me what temperature the fan switch should operate at ? both switch on and switch off temperatures .The stack is telling me that the water temp is between 80 and 85 degrees on my R400 depending on whether the car is sat in traffic or on a run ( hot day ) once the fan comes on it doesnt seem to go off.Drove back to London from North Wales yesterday ( thats another story ) and every time i stopped the fan was on even if temp was at 80 .Fan doesnt run when engine is cold. Do they all do that sir? Edited by - Mark w on 18 May 2004 10:42:41 Link to comment Share on other sites More sharing options...
Weirdy Posted May 18, 2004 Share Posted May 18, 2004 *sigh* What size Rad have you got, this seems to be a K issue with Caterham having fitted slim, (read cheaper), rad than can handle it.... I have a triple pass Rad and the biggest fan, and now Minty rarly goes into 100+ even last night after a hard run, I hit traffic to pick up the wife, the fan was on, but the engine WAS cooling.... Hyperion have been a great help with this problem, infact it was Dave and Doug that sighed first when I said she was over heating.... and pointed at the RAD and FAN as the quickest cheapest alternative to a piston head meltdown caused buy constant over heating and a twisted cylinder insert...... Hope this helps..... Weirdy One Happy SV VHPD speeding Monster Link to comment Share on other sites More sharing options...
Mark w Posted May 18, 2004 Author Share Posted May 18, 2004 The problem doesnt seem to be the engine overheating ( 80 ish is Ok isnt it ? ) more the fact that the fan doesnt go off ,even on the motor way . Link to comment Share on other sites More sharing options...
Weirdy Posted May 18, 2004 Share Posted May 18, 2004 You need to adjust the thermostat setting for it coming on, or the thermostat unit is duff..... At least a grands worth or rad fan and sump are not needed :-) just a small adjustment at best and at worst a new thermosta unit :-) Its s small job do-able by yourself..... Weirdy One Happy SV VHPD speeding Monster Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted May 18, 2004 Support Team Share Posted May 18, 2004 New fan switch is £10 from Caterham or do a search and you will find the VW part number and the pattern equivalent available from all good auto factors (or failing that Halfrauds ) for less than £10. I believe that the fan should come on somewhere in the mid 90's (92 or 95 ring a bell) and then go off again somewhere in the high 80's (88 maybe). Bear in mind that the thermostat doesn't open until something like 88 deg or 82 deg depending on the one fitted so the fan doesn't need to come on until much higher. The fan switches are notoriously unreliable and the cheapest and easiest way of checking is to replace it. It would probably be worth getting a spare as well. You can fit them without draining the cooling system as long as you are quick - unscrew old one and stick finger over hole then quickly screw in new one. Top up the coolant if you lost a significant amount, run the car up to temperature, stop and unscrew bleed valve until air gone and water comes out. Shaun Yellow SL #32 Link to comment Share on other sites More sharing options...
Myles Posted May 18, 2004 Share Posted May 18, 2004 If you jack/ramp up the front of the car as much as possible, you'll lessen the coolant losses as well... You need to adjust the thermostat setting for it coming on..... Erm, how on earth do you do this? I wasn't aware of any adjustment potential at all.... ...now, personally, I just need to search the archives for instructions on how to wire in a fan-override switch... Keep BC free and open for ALL. Membership No. 43xx Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
Mark w Posted May 21, 2004 Author Share Posted May 21, 2004 Sorted apparently i had an R500 switch which operates at 75 degrees. Link to comment Share on other sites More sharing options...
Jason Plato Posted May 21, 2004 Share Posted May 21, 2004 Weirdy - you are mistaken on several facts . You cant adjust the radiator thermostat for when it comes on , unless you buy a new switch with different settings or have an ecu with adjustable settings . The thermostat in the cooling system will only manage the temperature of the coolant not the fan switch There is nothing wrong with the road rad , I have used one for the pased 2 years with no issues and >200bhp , with a 78C stat . It maintains 78C on the guage even after 30 mins on track . as for "twisted cylinder insert......" now I have no idea what you are refering to ....... Edited by - Dave Jackson on 21 May 2004 15:16:48 Link to comment Share on other sites More sharing options...
Pleasantville Posted May 21, 2004 Share Posted May 21, 2004 My R500 has triple-core rad and big fan. Fan comes in at 72-74, goes off anywhere between 72 and 77. Sounds mad, but fan cut out temp seems to vary. It will come in at 73, temp will continue to rise to 77, fall to 74 and then cut out again. This is in slow traffic or when stationary. At decent road speeds the temp is 60-70 and the fan fast asleep. Link to comment Share on other sites More sharing options...
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