Temperature Guage Not Working

[Buncers]

The temperature guage in my TDI is not moving. Stuck at cold.

 

I had the thermostat changed last year and everything seemed OK for a while.

 

The thermostat doesn't seem stuck since all the hoses etc are getting warm/hot.

 

Any suggestions how to track down the problem?

[Andrew T]

Is the Auxilliary Heater working OK ?

[Guest galaxykid]

Does the heater kick out hot air? is the engine actually getting up to temp? if it does?check the temp sensor is plugged in? it's on the front of the engine clipped into a coolant hose? ;) check the condition of the wires as well? as they get brittle with age and snap!

[Scorpiorefugee]

I go with GalaxyKid.

 

Your heater will tell you if the engine is up to temperature.

 

The sensor has 2 senders. The one for the gauge appears to be totally separate from the one that the ECU uses. The glow plug lamp is a good guide to the operation of the other half. i.e. about 15 seconds when very cold to a second or so when hot. Do be aware of the point about the wires. the most likely is the earth wire breaking off at the lug.

 

The two sensors can fail independantly.

[Buncers]

Thanks for the responses.

 

The heater kicks out hot air, but I can't find the temperature sensor. Could you give me a better idea of how to find it. Picture, if possible

 

 

Thanks

[Scorpiorefugee]

It's not easy and depends on the model. A Picture is not easy either 'cos you have to take bits off.

 

It is mouted on a plastic lug coming out of the head at the front of the engine not far from the gearbox end. It has a 4/5 pin connector clipped into place and the device itselv fits in a tubular sleeve with an O ring to act as a seal. There is another clip which holds it in place.

 

You need to take the top cover/soundproofing off the top of the engine and, on mine, it is hidden behind a greenish plastic filter/coupler which is part of the emmision control system. This has to be removed also. It's a mucky job and you'll probably skin your knuckles if it's an old dirty engine like mine. ( another reason I'm reluctant to take a picture)

 

I paid about

[Buncers]

Took off the top cover and had a good look around. Not too mucky.

 

Still can't find the temperature sensor.

 

Is it actually plugged into the head or the block (below the head)?

 

What shape and size is it?

 

Is it metal coloured, black or something else?

 

Is it on the front side of the engine as you face the car from the front, near the gearbox end (so to the right).

 

What does the connector(s) to it look like - 5 pin with clip?? There seems to be a couple of these in the vicinity but not fixed to the head or block.

 

 

 

Any help most appreciated

[Guest MATT]

what if bouncers took a few photos, and those who know what there talking about, highlight where it is?

 

MATT

[Scorpiorefugee]

I have a picture but I can't work out how to shrink the file size to send it!!!

 

Anyway.

 

On the top of the engine is the black rocker cover.

Below that is the Headand near the right hand side of that, looking fron the front, is a 2" (approx) rubber pipe going ito the head via a casting.

 

The temperature sender plugs into the right hand side of this casting somewher at about the same level as the wires for the glow plugs and (in my case) right behind a green plastic thingy which must be removed to get any where near it.

 

The green plastic thingy is about 4" long by 2.5" diameter.

 

Sorry I can't send a picture, I was a mainframe programmer for 12 years but I hate PCs and windows! :o

 

Blooming over rated games machines! :huh:

[Buncers]

Thanks guys - I'll have another look when the car comes back from its MOT.

 

Probably take some pictures too.

[Buncers]

Photo attached - this is what I see from the front of engine (right side of block)

[bigdaddy]

This is ur engine temp sensor,,,,,,,,,it doubles as ur temp gauge sender,,,,,,,,,,,,,,,disconnect the wire,,,,and remove the clip, the sensor will come out,,,,recover the sealing ring,,,,,,,,,,refit NEW sealing ring and push the new sensor in and refit the clip and wiring plug,,,,,,,,, :o

[johnb80]

The glow plug lamp is a good guide to the operation of the other half. i.e. about 15 seconds when very cold to a second or so when hot.

I can't agree with you on that one, mine never glows longer than acouple of seconds no matter what the weather, in fact it doesn't vary at all.

 

Regards - JB

[NikpV]

definitely the light is on for longer if its cold but never 15 secs, more like 4/5 in very cold weather on our Gal

[Scorpiorefugee]

Just to clarify...

 

 

When you're sitting in the cold waiting for the D.....d thing to go out, maybe 5 secs seems like 15. If you disconnect the sender, it's certainly nearer 15 sec 'cos it then thinks that it's real brass monkey weather.

 

If yours doesn't change, methinks you may have a problem. Mine used to start quite well, even with no glow plug activity at all.

 

Another silly thing I've found. If it thinks it's very hot, even if the glow plug light comes on for a second, the feed to the glow plugs is never activated. I know this 'cos I've had it. It is quite possible that there are different version of ECU and that the glow plug light does not alway indicate what is happening.

 

It seems that there is more to this than meets the LEDs on the display. As I pointed out in a post a while ago, it would be helpful to know EXACTLY what the management system is programmed to do then we could make a list of simple unplug/short out tests to help each other and avoid going round in circles looking at misleading symptoms.

 

I did this with a range of video equipment years ago and it then became possible to diagnose any fault with a maximum of 6 simple tests and the control system of those things was and remains far more complex than anything used to control a motor car.

 

Ahh well.... dream on! :(

[Buncers]

Still trying to fix this problem. A few questions:-

 

 

1) How do you remove the wiring connector clip without breaking it?

 

2) I found a dangling spade connector coming from the bunch of wires marked (red arrow), any idea where it should be connected?

 

3) If I remove the wiring connector from the temp gauge, could I test the current coming from the sensors. Any idea what current should be coming from the pins?

How do I find out?

[Masked Marauder]

1. Push the metal clips on the side in when you pull.

 

2. Some models have two oil pressure switches. The spade connector is for that.

 

3. You are measuring resistance, not current. Personally if I were going to the trouble I would just replace the sender. They are not expensive in the bigger picture, although in your case I would connect the wire back to the dash to ground and the gauge should read off the top end of the scale. That should prove the gauge works.

[Buncers]

Thanks - I'll try to test it out before going for the replacement.

 

Fraud want

[Masked Marauder]

Thanks - I'll try to test it out before going for the replacement.

 

Fraud want

[Scorpiorefugee]

Mine was a slightly different fit but It went in OK. I think I had to take to O ring from the old one. (And this was supplied by FORD!!!)

 

Don't forget to check for broken brittle wiring - especially the earth connection.

[Buncers]

I tested the gauge as advised, connected wire back to dash to ground, and gauge went off the scale.

 

So I need a new sensor. Rang a few factors. The first had a choice of 2 and needs to see the original. One guy at Unipart recons I've got to get it from Ford.

 

Any suggestion on factors (national ones) or Cambridge area, to try.

[Buncers]

Fitted new sensor at weekend (

[Masked Marauder]

Marvelous, another happy motorist.......