rad temp thermo

[Lollypop]

hi folks ive looked before postin this but need help/advice,my van is tintop 88 1915cc df,drove 80 mile then got stuck in traffic and the header tank split,temp gauge was passed halfway most of the time,appened 5 mins from home so let it cool and put elec tape over the split and more water in and got home,emptied system and flushed out,fitted new header tank+dalek cap+rad thermostat,filled system with 8.5 litres cooolant and could only get bout 6.5 litres water in,just bought the van so checked a few things,see photos,cleaned up the earth crowns,haynes says the wiring for the rad thermo should be red/white in middle with red blue and red black outside,my rad thermo plug has the red/white on the outside does this make any difference,i switched them over,put red/white in middle and bridged connections and the fan works in low and high speed but doesnt come on when the coolant is really hot in the header tank,also ive looked at the relays and the one for rad fan,53,is upside down,is this right and is it in the right place?.http://www.flickr.com/photos/lbbarney/s ... 693678140/" onclick="window.open(this.href);return false;

[Oldiebut goodie]

I have never had my coolant hot enough to get the fan on yet in all the years that I have had it. Everything is shipshape - sender, wiring on so on but still haven't managed it. I think that a lot of people are the same and the fan doesn't kick in until the temp gauge is reading up around the 3/4 mark and then the system has to be pushing that hot water around to the radiator. So if you have a slightly sluggish water pump and slightly ineffective thermostat you may not get that hot water as far as the radiator to trigger the fan switch.

[kevtherev]

That's the thing really
The gauge is reading from the thermostat housing where cooled coolant and hot coolant mix, the thermo switch sits in the hot coolant direct from the engine.
so the two will be different.
The low speed fan comes in at 93-98 deg ! and the second speed at 99-105 deg!

the thermostat starts to open at 85...which is about what the gauge sits at, so as oldie suggests it won't kick in until that coolant hits the thermo switch at 93..

personally I have had the gauge at just over the mid point, so no drama...but the second speed triggered .. just after a short high speed run and then a stop in traffic