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Temperature warning light

claude van rouge

claude van rouge

Enthusiast
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203
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Saône-et-Loire (71), France
The temperature warning light on Blanche is coming on intermittently, the water level is at max and the fan doesn't come on (it does work!).

I did remove the sender the other day - and there was a small washer underneath it - which seemed wrong to me so replaced it without the washer - is the washer meant to be there?

Any thoughts?
 
My fan wasnt working
just replaced the fan switch on the bottom of the radiator now its fine
 
Sorry Mattt the fan works fine (the switch was replaced about a year ago) it is just that the temp warning light comes on before the fan starts up.
 
So long as the radiator itself is full of water (pull the cap off the radiator rather than looking at the expansion bottle to check) then it's the sender that's faulty.

Could be an air lock of course - worth undoing the heater bleed screw that sticks out of the bulkhead to check there's no air in the head.

If there's loads of water in the engine and no air locks it's definately a faulty sender/ wiring or light. Should only come on after the water has left.
 
just to remind everyone not to ignore tempurature light as working correctly it will only come on at 115 c and continuing to drive will then seriously wreck engine
mind you if it doesnt come on when it should do ,funny rattling noises and loss of power may provide a clue !!
have definitly had probs with senders coming on too soon , i have got a fancy hand held infra red thermometer i use to verify actual engine temp and check fan comes on at 85c

paul
 
I had same problem - warning light came on before fan came on. Bled it many times and the water in the expansion tank was not boiling. Turned out to be faulty sensor on the engine.

For me, the only thing that the 4 is missing is a temperature gauge. A warning lamp is useful, but not as informative as a gauge.
 
I am agree with jjad.

I installed a long time ago a temperature indicator to my R4.

Here a picture.

indicador.jpg
 
Excellent work! Where did you put the sensor for it? Where the warning lamp sensor goes?
 
Update on my original post:

Having checked that the system was bled properly the light was still coming on so I swapped the sender with the one from Claude - all seems OK so far.

Mind you it could be that the sender from Claude doesn't work :?

We are off to Clementines Renault 4 Garage with Blanche for the w/e - so hopefully the great minds of Clem and Frederick will sort us out if we still have problems :D
 
Hi.

Jjad. I installed a new sensor on the cylinder head. Look at the picture (red box the green circle is another possible place to fit it).

termistor.jpg


I left the temperature alarm sensor in its original position.

Jon
 
The washer you described is for sealing purposes, although it doesn't leak now you cannot guarantee it will not when under pressure...better fit a new one.

I have fitted sensors for temp gauges both on the original position (it tends to be optimistic...) and on the rectangular plate on the rear of the head (reads high due to reduced water circulation there). Both are way better than the stock "too late light" though.
 
I bought a water temp gauge a month or so ago but have no yet connected the sender. Does the gauge sender have to be fitted to the head to give an acurate reading? - can it not be fitted in line on the rad hose with a special hose adapter ?

Please could you give me a little how to on fitting one to the head :wink: ?

Cheers, Matt
 
I don't think it is good mounting the sender to the hose, since it will monitor water temperature only when the thermostat is open.
Mounting the sender is staightforward (exactly like on jon's photo).
 
I am agree with Angel. If there is a water leak and finally the system gets empty which temperature will measure the sensor? Perhaps is to late to wait the steam to heat up the sensor (if there is water enough of course on the system).

I prefer to know the head temperature because if this is right, we know all the cooling system is working fine. Perhaps the reading is not as fast as in water but in my opinion is safer and perhaps more realistic.

I also installed it on the right side of the engine because on the left side readings are higher due to the heat coming from the exhaust (I have tested it and the correlation of the back right side is good regarding to water temperature).
 
I'm having too problems with temperature warning light.

It's started in the summer. It was the first summer I really owned the car. I don't know if my grandfather had any problems with this earlier.
So when I parked the car in-front of the garage and went to open it. When I came back the light was on and the fan was working. That happen regular. But only at home so I didn't gave a attention to it.

Today I was driving on step long hill in 3 gear 60-70 km/h and always had the pedal pinned down. It happened in both ways right under the top, so I continued to drive because the down hill cooled it down in a bit.

The expansion bottle is between min-max. Temperature outside was between 20-25°C.

Hope someone has an idea for help :)
 
jjad said:
I had same problem - warning light came on before fan came on. Bled it many times and the water in the expansion tank was not boiling. Turned out to be faulty sensor on the engine.

For me, the only thing that the 4 is missing is a temperature gauge. A warning lamp is useful, but not as informative as a gauge.
Click to expand...

So you're saying if it's owerheating then the expansion tank should boil. I'll take it for a spin this weekend and stop when it's on and have a look.
 
Today I drove somewhere, it was ca. 15km. And I was driving pretty aggressive. As I parked there and didn't turn-off the engine immediately the temperature light came on. I left the car running and the open the hood. And the watter wasn't boiling and the fan wasn't spinning. So I can conclude that it isn't overheating, so something is wrong with the sensor.

@Malcolm: As you suggested to someone else I wanted to pull the radiator cap off to check. And I read "DO NOT OPEN". Should I open still this or you meant something else.
 
Me? Oh heck. I would suggest waiting for the car to be cold and then removing the radiator cap to see if there is water in there. If there is water to the top then there is probably water in the system.

If there turns out to be water in the system then the car is probably not overheating. Those sensors are rubbish. But it's worth checking before assuming it's the sensor.
 
Yes I'll look tomorrow into the radiator, I only thought that if I ignore the warning I could do something wrong.

Tnx, for the quick reply.
 
Today I took the remove the radiator cap, and the water was slowly puring out. So the is 100% water in the system. After that I disconnected the sensor and attached the cable to the "ground", started the engine and the light was there. So the cables are fine. The sensor is Jaeger D5.

I'll borrow and infra red thermometer next week and I'll go for some serious uphill drive. When the light would light I'll measure the engine temperature. So I will be able to tell if the sensor from the fan is going crazy or the one from the engine.

Tnx, for your help malcolm.
 
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