Fan On Constantly

[Longboarder]

Sounds like you have sorted it. 98/93 should be about right. Just make sure it has the right thread to fit. If not keep searching. There are plenty of those switches about in all different threads and temperature ranges.

 

Nigel

[Guest b3nny]

Researched that the hole in the race line housing it m22 so I'm going to order the said switch now.

 

 

Thanks for your help

Edited July 6, 2014 by b3nny

[Guest snowy2]

i have not read the whole post so excuse me if this has been suggested..is your fan switched via a relay?

if so i would suggest that the relay is a 5 pin relay and the fan is connected to pin 87a not pin 87.

 

Oh and 22mm X 1.5mm thread switches are VERY common in the automotive world they also come in a huge range of switching temps (two temps for VW's twin stage fans) the temp ranges of 85-95 are very common on earlier cars (1980's cars) and i buy the XR2 Fiesta fan switches.

Edited July 7, 2014 by snowy2

[Guest b3nny]

Hi snowy, it's ok bud it's all sorted now a previous owner had taken the wires from the fan switch and joined them together meaning the fan was on constantly running with no stat (god knows why!) I found the wires disconnected the circuit and hey presto the fan stops connected them to my existing fan switch and it cut in when it should, just waiting on a switch no that comes on at 98 and off at 93 as I'm running a blacktop and they seem to run horror than most.

[Guest snowy2]

i believe that zetec engines are designed to run a bit hotter than most older engines.......just bought one for my new project car(s) it also seems they are very fussy about the quality and weight of oil as well (so depressingly expensive synthetics from here on rather than cheapo 20/50 mineral oil)

[Guest b3nny]

So fitted my new fan switch and now it tends to turn on and off when it feels like it, it's a 98-93 switch yesterday it turned on at 62 and today it turned on at 83, is there something obvious I have missed?

 

Could it be controlled by the megajolt ecu and between the ecu and the switch its getting confused?

 

[Guest Gargoil]

If its just a fan switch that is operating your fan, it shouldn't have anything to do with your ECU.

How are you measuring the temperatures?

[Andy Spencer]

i believe that zetec engines are designed to run a bit hotter than most older engines.......just bought one for my new project car(s) it also seems they are very fussy about the quality and weight of oil as well (so depressingly expensive synthetics from here on rather than cheapo 20/50 mineral oil)

Zetecs are fussy but you don't need very expensive fully synthetic. The Ford spec 5W30 semi synthetic is the way to go and you won't have any problems, not that expensive either - the Supermarkets stock it as well as the usual other outlets such as Halfrauds.

[Longboarder]

You potentially have three senders reacting to coolant temperature, all in different places. Megajolt sender should be in the rail and requires a correct calibration for the sender to be entered in the megajolt to give a correct reading. Gauge sender may be in the rail but slightly different position to the ECU sender. Again needs to be matched to the gauge to give correct reading. Fan switch sender is in the stat housing and just reacts to the on/of temperatures by switching.

Manufacturing tolerances will give some differences in the temperatures registered. The two temperature senders will register change faster than the fan switch. Water flow differences with stat closed/part open/fully open will give differences. Efficiency of the design/manufacture/finish of the fan switch will give differences. They are usually a heat reacting bi-metal mechanical device and a bit crude compared to the senders. That may be the best it can do or it may be faulty. It may improve with time. You are also looking at the working details of what's going on more closely than most of us ever have.

Assuming you have sorted the rail flow to be fairly consistent I would either be worrying that the fan switch you have fitted is not very good quality or would be ignoring it for a while and revisiting the problem in another 500 miles and many cycles of operation to see if it continues to be inconsistent.

 

Nigel