saph cosworth overheating problem
 

the fans aren't cutting in in my 4x4 saph. If i short the plug out that goes on the fan switch, the fans run.

so i thought it was the fan switch. i bought an uprated one from MSD and fitted it. i ran the car up to temp and i let it get to 94C but the fans still didn't cut in.

i have felt the bottom corners of the rad and it does seem hot but the angled part at the very bottom doesn't seem to be anywhere near as hot as the other side. could this indicate the rad is partially blocked?

any help would be great

cheers Matthew

Yes it does seem as though that could be the problem, got to be worth flushing out to find out.
tabetha

cheers, the rad is a standard one and the car is quite high powered so i've just ordered a alloy rad for it, so hopefully it will sort the problem out

cheers Matthew

As said don't throw the old one, may just need flushing, the power of the car dosen't matter, the alloy one you have though will just dissipate heat better due to the material being a better conductor of heat, a bonus is it's also lighter!

Don't fit the terrible standard switch to the alloy rad as it suffers a heatsink effect and your fans won't turn off once they come on! The 'Uprated' switch is better anyway as the span is just a few degrees opposed to the 9 degree span of the standard which is what leads to melting fuses.

Also it's worth rewiring the fans and checking the voltage at the fuel pump UNDER load (You want to be seeing alternator power ideally but so long as +12V is maintained. Plenty of info on the rewire on here, wiring is DIY or can buy the looms pre made as well, these are two chronic weak points!

Martin

cheers for the info Martin, the wiring lookslike its ben upgraded at some point.

cheers Matthew

I very much doubt the alloy one is going to be lighter, certainly in the case of airtec they are not as light as the std rad.
tabetha

mate same thing happened to mine and mine was alloy one at the end the rad was blocked just flush it.

hi not sure if you got the rad out yet, but if you have a hose handy try filling it from one end and see if the water comes out as fast as your putting it in, if it backfills quite quickly you know theres a blockage. if the rads been sitting for a while the sludge might have hardend and blocked areas, a good flush as mensioned on previous posts should sort it :)
standard rad and fans on mine.. they work perfect together.

not got it off yet, going to try and remove it today so i'll update the thread when i find out

cheers for the comments

Matthew

fitted my new alloy rad and uprated switch and the fans cut in and out as they should, so must have been a blocked rad, as this ally one gets to hot to touch where the fan switch was but the original one you could touch

cheers Matthew

Be worth maybe putting in a 82 degree thermosat too. that helped mine out too aswell as the uprated fan swith. My fans come on at 95 degrees and off my 88/89. i heard that people drilled there thermostat for a constant flow or something like that a while back too.
glad she is working again for you.

the fans cut in at about 88/90 and go off at 82 according to my secs monitor

cheers Matthew

A 82C stat will do NOTHING to protect your engine, over a 88C stat, I use a 88C even now in the summer, just have to reset my ecu to on at 98C and off at 95C, high temps don't kill HG's, boost does, but some people pray on cossie paranoia with HG!!
In the old days some drilled a small 3-4mm hole in the stat to assist in dispelling air and preventing air locks, but with using a expansion tank system and having a nice free flowing pipe from highest point on engine to tank this isn't needed, and it slows the warm up time down markedly.
tabetha