water temperature issue

[Andy1912]

Hello,

I am a fairly new Caterham owner - the car is a 1998 k-series that has been upgraded with a r400 engine. Anyway, over recent times all has been well.

However, on a drive today I noticed an issue with the water temperature. What is happening is that immediately after switch on the temperature gauge moves up to about 110 degrees, and then slowly further up to 120 degrees. This is on the cusp of the red zone.

Coolant level look fine.

The only issue of note is that yesterday the car did seem to be overheating and when I got home I was fairly low on oil, which I promptly remedied.

Any ideas about what the cause of this may be and any thoughts about whether I should stop driving it / take in to a garage?

Thanks for your any advice...

Andy

[Andy1912]

sjmmarsh said:

Andy

What (apart from the gauge) symptoms made you think it was overheating? Failure of the temperature sensor is quite common so it is worth changing that, but if it is overheating I'd check the thermostat on the radiator first - if the pipes are hot but the radiator is cold, it is likely that the thermostat has jammed shut.

Steve

Thanks Steve. I have had a closer investigation today.

Not sure it is overheating. I ran the engine, stationary, for about 30 mins this morning. The radiator remained fairly cool. The fan kicked in for a while after about 20 mins then stopped. The supply side pipes to the radiator are fairly warm, but the return side are pretty cool. All the while the temperature gauge read between 110 and 120 degrees.

The gauge operates as a switched oil/water temperature indicator and the oil readings are fine. So on the one hand I am thinking it's not the gauge. On the other hand, I am thinking that if it is the sensor then why isn't then sensor output triggering the fan?

I'm no mechanic as you can probably tell, but I have a decent understanding of electronics having been an engineer a few decades back...

Thanks again for your help....

Andy

[Andy1912]

DCL said:

No 100% sure about your car but the fan is probably controlled by the ECU and has its own sensor. The gauge sensor normally only does the gauge.

Thanks for that which is good news. I'll see if I can find the parts number and order another temp gauge sensor.

[Andy1912]

BertBert said:

Or the fan is controlled by the switch in the top of the rad.

The temp sensor in the water rail is duff. Change it and all will be well.
Bert

Thanks Bert

[Andy1912]

Hi

I have been looking at this today again. It's a warmer day bit the hose that the temp sender sits in is quite hot, and likewise the radiator. I also can't see the coolant circulating - though not sure if I should - I am assuming so.

Anyway, I would like to do the easiest thing first, because the gauge reads 100 degree + even without the engine switched on, and replace the temperature sender. It has a few markings - "46 / 10" and "6811" and below the latter "-0.3". It is like a previous poster indicated, small brass with one connection. Can anyone point me toward somewhere I can buy another one?

Many thanks

Andy

Edited by Andy1912 on Sunday 5th April 15:38

[Andy1912]

Many thanks for the pointers. I have ordered a new sender from Caterham which should be here in a few days.

Andy

[Andy1912]

Delivered and fitted. Temperature no longer a problem as advised so many thanks all.

The new version of the sender has a different odd connection. I have managed to squeeze the old connector on but its all very Heath Robinson. Is there an adaptor or connector that I can crimp to make a more solid and professional connection?

Thanks

Andy

[Andy1912]

Yes that is the one, thanks for the pointer.