Water Temp Confusion

[dd1961]

Folks, I'm hoping someone can help unconfuse me as to what it going on.....

 

K-Series 1.8, with a Stack dash.

 

From cold water temperature creeps up until it reaches 105c and then the fan kicks in, at which point the temp reading jumps to 110...fan runs until the temp drops to 103 when the fan stops and the reading immediately drops to 98c...

So, there is obviously an earth problem with causes the temp to increase 5c or so when the fan kicks in....but the temps seems pretty high as well. Shouldn't the fan kick in at 90 or so?

Oh, and the other thing that has me scratching my head, is all the temperature threads here refer to a temperature sender with a single connection...there are two senders on the water rail, the front one has a plastic snap on connector, which I assume is for the ECU, but the rear sensor, which is for the Stack has two wires connected.....is this something peculiar to the Stack system?

Any thoughts gratefully received!!

 

[Graham King]

The fan is controlled by a sensor in the rad itself, mine is rated at 98/92 (i.e. on at 98 off at 92). Depending on where this sensor is (top or bottom) it is likely it sees a different temperature to the sensor in the water rail hence it the higher readings at which the fan apparantly turns on/off.

 

I can't comment on the jump/drop in temp unfortunately.

 

Graham.

 

R7 GPK

Superlight #85

[dd1961]

Thanks Graham,

 

My rad sensor is at the top, so fairy close to the water rail, a temperature drop of 7C between the sensors seems quite large?

 

DD

[Archie Procter]

Sounds like one or both of the water rail senders has failed - one is to the ECU as you say and the other is to the gauge (or Stack in your case).

 

My ECU sender was showing something like 115 on the diagnostic equipment which is clearly wrong. I would try replacing the sender to the Stack in the first instance - better still if you can borrow one from someone else before investing the £30 or so for a new one. If it still happens have a look at the wiring into the Stack IMO.

 

Agree it sounds like you have some kind of earthing issue that causes the 5 deg jump when the fan cuts in, earthing issues are really common on K's. There are several earthing points in the engine bay and it could be any one or several of them. However if your issue is the Stack wiring as above I would suggest it's most likely to be causing this as well.