Fan, Temperature sensor and temperature gauge issues.

[GWFBall]

Hi
I've just bought a cheap 1997 Rover 414 1.4i. After a week of trouble free driving back and forth work, I started her up from cold this morning and the temperature gauge shot straight up to the red and stayed there (flickering violently, but staying around red and beyond), clearly the engine is not hot if its just been switched on. In addition to this, the cooling fan doesn't kick in either.

I've checked the car over and there are no obvious signs of Head Gasket issues, I am not loosing any water, the oil is still consistent, no residue on the oil cap, rev's appear fine, no smoke from the exhaust or noticeable leakages.

I'm of the opinion that this may be a temperature sensor issue. Can you confirm or deny this and explain to me how these sensors work (or not in this case) in relation to the problems I am having? The more I understand, the more likely I will tackle the problem myself by way of purchasing and fitting a new sensor or sensors.

(P.S. the fan does work but doesn't kick in. Surely if the temperature reading is in the red the fan should kick in, but I unplugged the temperature sensor whilst the engine was running and the fan kick in straight away so the fan seems to be in good working order. I'm confused.......... so, in summary - The temperature gauge shoot straight into the red regardless of whether its a cold start or not and the fan doesn't kick in when this happens) HELP!

[dazultra2000]

Sounds like the coolant temperature sensor is working, but it's readings are being displayed incorrectly.

I would guess that this is either an ECU or dial problem.

Unfortunately that's the limit of my diagnosis I'm afraid.

[GWFBall]

Cheers for that, but the 414 has got 2 temperature sensors?????????? Why I don't know but the coolant temperature sensor is black and the other just above it is brown, its the brown one I unplugged to get the fan to kick in..... This fixed the problem temporarily, the gauge went back to normal for the duration of my journey. However, when I started her up the following day the gauge shot straight back up into the red again (the sensor was still unplugged) WTF!!!! AARGH!

[s495kbl]

The brown one is the ECU feed. The BLACK one as you say should infact be BLUE and thats a one wire plug that feeds the guage.

I would suspect a loose wire or that sensor is faulty.

[GWFBall]

Could it be that somebody has installed the wrong sensor for that model given the fact it should be blue?

Thanks for that, i'll check it out tomorrow and report back.

[s495kbl]

Could be, but ones from a motor factor will be black as they dont colour code them like OEM stuff. So the brown one would also be black if it was replaced for a factor sensor not OEM.

Also the brown one controls the ECU and the cooling fan, hence why the fan came on when it was unplugged so thats all good. It just means the temps not high enough to trip the fan on yet.

I would replace the black sensor with another and check it works if not it has to be the guage itself.

[GWFBall]

Ok, s495kbl you are being a big help dude.... keep it coming.

So, today I unplugged both sensors and the car was running as sweet as a nut (The fan was on constant obviously, but better that than not at all eh)? The temperature gauge though, went straight to red and stayed there.

This may sound a bit silly but, if the gauge itself is faulty then wouldn't it stay put when the engine is switched off and the key is removed? This is not the case, it returns to flat line when I remove the key.

(This is assuming that when you say a faulty gauge, you mean the needle is stuck in position or something similar)

P.S. Where would you recommend purchasing a (Blue) Coolant temperature sensor, where can I find original equipment manufacturers for Rover parts (don't fancy using the scrap yard)?

Thanks again buddy.

[Gareth1982]

My sensor on my 414 went kaput. But my gauge never moved, even after running the car, infact it dropped very slightly from the "0" mark. Got a new sensor from our local Rover parts supplier. You have the sensor on the top which is brown, for the fan, then underneath that pipe is another one, which is blue



Advice would be to change that and see what happens. The gauge itself in mine has been replaced too. Found one at the breakers and took the clocks out and just swapped them over.

Worth a try.

[GWFBall]

Originally Posted by Gareth1982

My sensor on my 414 went kaput. But my gauge never moved, even after running the car, infact it dropped very slightly from the "0" mark. Got a new sensor from our local Rover parts supplier. You have the sensor on the top which is brown, for the fan, then underneath that pipe is another one, which is blue



Advice would be to change that and see what happens. The gauge itself in mine has been replaced too. Found one at the breakers and took the clocks out and just swapped them over.

Worth a try.

Cheers buddy, the fact that yours needle didn't move noticeably doesn't discount the fact it too may have been broken. Anyhoo, thanks Gareth that's a big help. I'll probably change the sensor first and if the needle remains a problem i''l replace the gauge too. How much did you pay for the the parts buddy? I know a sensor is around £10, what about the gauge?

[Gareth1982]

Originally Posted by GWFBall

Cheers buddy, the fact that yours needle didn't move noticeably doesn't discount the fact it too may have been broken. Anyhoo, thanks Gareth that's a big help. I'll probably change the sensor first and if the needle remains a problem i''l replace the gauge too. How much did you pay for the the parts buddy? I know a sensor is around £10, what about the gauge?

Gauge was about £2 from our local breakers. BUT they are very good on prices and don't over charge. So I would expect realistically anything from £5 - £10. and it wasn't the gauge as the 'new' one did the same. My Uncle (who's an electrician) shorted the connection and sure enough the gauge rose to the top. So it was definitely the sensor/switch.

[GWFBall]

Ok,

So I've looked around pretty comprehensively for an OEM Coolant Temperature Sensor. EVERY supplier out there that claims to sell original parts only supply the black sensors, yet if what you guys have said is true then these are NOT original parts because the original part is blue????????

ERM..... who's fibbing and who's not? Haha! Could it be that the black ones are original parts except for the fact that they didn't come off the factory line fitted to to the car unlike the blue ones that did come with the car????

This is crazy, as long is it works I don't care what bloody colour it is.

[Gareth1982]

Originally Posted by GWFBall

Ok,

So I've looked around pretty comprehensively for an OEM Coolant Temperature Sensor. EVERY supplier out there that claims to sell original parts only supply the black sensors, yet if what you guys have said is true then these are NOT original parts because the original part is blue????????

ERM..... who's fibbing and who's not? Haha! Could it be that the black ones are original parts except for the fact that they didn't come off the factory line fitted to to the car unlike the blue ones that did come with the car????

This is crazy, as long is it works I don't care what bloody colour it is.

Mine is blue, I think however the one that was on it was either green or black. I can't remember exactly.

If you want to be 100% contact the same place the garage got mine from (our local MG-Rover spares store..ironically a Ford Garage )

Parts: 08448 22 56 40


I know maybe it's not close to you, but they should be able to give you some indication. But mine was definitely blue, as you can see it in the photo above.

Or Ring RimmerBros on 01522 568000 and they should tell you.

[GWFBall]

Thanks buddy, I'll give it a shot.