Coolant water temperature sensors

[dnb]

I believe there are 2 of these in a MY96 500. Am I right?

I think I can see one in the swirl pot. Where is the other one? In the block somewhere? And what job does each one do? (I presume one does the ECU cold start and the other does the temperature gauge)

I'd look this up in the bible, but I've only got the 1st edition and it doesn't seem to go into that much detail...

Thanks.

[shpub]

You need the 2nd edition....

Swirl tank is not a temp sensor it controls the fans only. Top of engine by the plenum is the ECU temp sensor. Instrument temp sensor is hidden behind the distributor. There may be a third temp sensor near the alternator. Some have it. Some don't. Not used and not the same spec as the others.

Steve
www.tvrbooks.co.uk

[dnb]

It's on my christmas list!!

Thanks for the info.

Typical, isn't it - the thing that I know works is the easiest to get to...

[david beer]

I use the spare sender, so do many others when the original temp sender packs up. The spare will not under read in cold weather though ! Its should be open to a vote, who uses it and prefers it ?

[Ballistic Banana]

david beer said:

Its should be open to a vote, who uses it and prefers it ?

and and to DB and his mod-wise installations

BB

[shpub]

What's a vote got to do with this?

Are there plans to enforce the use of the wrong sensor instead of the correct one?

[JoolzB]

david beer said:

who uses it and prefers it ?

I use the spare too and am more than happy with the reading the guage gives. It's probably more robust too so definitely preferable and less likely to need replacing, all imo.

[Ballistic Banana]

shpub said:

What's a vote got to do with this? Are there plans to enforce the use of the wrong sensor instead of the correct one?

Whys it wrong Steve.Just in a different place not to far away. After getting in that to that bloody gap to replace mine and then find out I was the wrong one. I was very happy to use Davids method and it also meant I could calibrate the Guage better using a IR themometer and the adjustable resitor on that sensor.

BB

[david beer]

There is no point to a vote, it was a way of getting across there is no reason not to use the Range Rover sensor. TVR only put theres in that hole to stop water pooring out, on a Rangie that hole is to the heater matrix.

[shpub]

To be honest, it depends on your viewpoint.

However as you say, it needs a calibration resistor to set it for a specific temperature which means having access to a thermometer of some kind, some resistors , a soldering iron and other odds and sods to do the adaption. The readings on the guage are only accurate for the given calibrated temp. If you have this stuff and don't mind the reading limitation, then it is an alternative. Is it better? Yes compared to a broken sensor. No to one that is working correctly. IMHO of course.

The original point I made was it is not the same spec or direct replacement which is true.


>> Edited by shpub on Thursday 16th December 06:32

[david beer]

I can see you are not going to agree Steve, but for me the fact it no longer gives the "my car runs at 60-70 on a cold day" is reason enough,you say so yourself, the air is cooling the original sender.So it does have reading limitations !!. As for setting it up, fans coming on is your set up point, everybody knows where theres is, twiddle the variable to have the same reading, and thats it.

[B16 RFF]

david beer said:

I can see you are not going to agree Steve, but for me the fact it no longer gives the "my car runs at 60-70 on a cold day" is reason enough,you say so yourself, the air is cooling the original sender.So it does have reading limitations !!. As for setting it up, fans coming on is your set up point, everybody knows where theres is, twiddle the variable to have the same reading, and thats it.

I find it hard to believe that the sensor behind the dissy cap is affected by cold air, because:-
a) Most of the air coming it's way will be heated by the radiator and the exhausts.
b) The bit that actually does the sensing is buried deep in the water jacket, well away from the airflow. The part exposed to the airflow is only the hexagonal bit and the connectors, and even that is shielded by the dissy.

Has anyone done any before and after testing with some sort of windshield fitted?

[aitkindrum]

i am using spare sender coupled with resistor detailed in david beers previous posts think about 150ohm. gauge reads about 10 degrees too hot. do i increase or decrease value of resist and by about how much.
ta ada

[2 Smokin Barrels]

shpub said:

What's a vote got to do with this? Are there plans to enforce the use of the wrong sensor instead of the correct one?

It's illegal to use the sensor. You can however connect the sensor and then use another instrument to actually detect the temperature. (Although the rules are different in Scotland). Drag sensors aren't as much fun.

[david beer]

Use an adjustable resistor,its easier, but to answer your question, lower to around 120ohm, an adjustable is 40p.
The original sender is on a pipe extension, so the end is not actually in the water flow, so it does get chilly. You could "lag" it i suppose !

[david beer]

So, dnb, what was your make on the sender subject ? Did you want to try the spare as yours was knackered ? It would be a shame if this message was not getting to people, so do give an indication !

[dnb]

I replaced the ECU coolant temperature sensor, and the car is much improved. The lumpy running, random stalling and higher than normal fuel consumption seem to have gone away for now...

The sensor itself was a Lucas 73355A (now called a SNB508 IIRC) bought from my local Lucas Service place and fitted by me.

I haven't tested the old one yet, but since the problem is aparently fixed, I'm not worrying too much.
The gauge one seems fine for the moment.

I can get on with performance mods now!

[griffter]

dnb said:

I replaced the ECU coolant temperature sensor, and the car is much improved. The lumpy running, random stalling and higher than normal fuel consumption seem to have gone away for now... The sensor itself was a Lucas 73355A (now called a SNB508 IIRC) bought from my local Lucas Service place and fitted by me. I haven't tested the old one yet, but since the problem is aparently fixed, I'm not worrying too much. The gauge one seems fine for the moment. I can get on with performance mods now!

I bought a replacement from Land Rover - it's no longer a Lucas, but now manufactured by Sagem! Wonder if the ECU can listen in on phone conversations...

[schueymcfee]

dnb said:

I replaced the ECU coolant temperature sensor, and the car is much improved. The lumpy running, random stalling and higher than normal fuel consumption seem to have gone away for now... The sensor itself was a Lucas 73355A (now called a SNB508 IIRC) bought from my local Lucas Service place and fitted by me. I haven't tested the old one yet, but since the problem is aparently fixed, I'm not worrying too much. The gauge one seems fine for the moment. I can get on with performance mods now!

Could you give the phone number please?

>> Edited by schueymcfee on Monday 10th January 15:19

[dnb]

I don't know if the number will help you, as they're on the Isle of Wight... Their number is (01983) 524819

Maybe a better idea would be to search for LSUK in the BT online Phone book