Jump to content

Temperature gauge reading low.


Recommended Posts

On the way back from Malvern (which was very good) about half an hour from home, my temperature gauge started to drop to about 1/4 way past cold. My gauge is always in the centre when up to temperature and never really moves much, occasionally in traffic on a hot day it will rise.

I’m assuming that the stat has stuck open. Is this a correct assumption? or is there any thing else I can check.

I’ve not touched anything as of yet.

Link to post
Share on other sites

I forgot to mention that modern wax type t/stats fail in the closed position unlike the

old bellows type that fail in the open position

                                                                             Harvey

Link to post
Share on other sites

Hi Kev

Sounds more like a possible bad contact at the temperature sender unit or sender wire to the gauge.

I'd suggest first cleaning the temp sender contact in the engine bay and check the wire where it connects to the spade for corrosion/oxidation before doing anything else and then perhaps change the sender if that fails to resolve the issue. 

Andy

Link to post
Share on other sites

I changed the thermostat after a similar problem but it made no difference- in my case it was the voltage stabilizer or its wiring. Maybe try  checking  for a temperature difference between the water pump case and the top of the radiator during warm up with a remote sensing IR thermometer.

Link to post
Share on other sites

Hi Kev,

you can check the T-sensor with an Ohm-meter. The value (resistance) changes with temperature. My sensor failed too, and I first checked the new sensor, there are different types that can confuse you and can give wrong readings.

Waldi

Link to post
Share on other sites
On 8/16/2021 at 5:12 PM, HSM said:

If the fuel gauge is also reading low, suspect voltage stabilizer on rear of speedo.

 

                                         Harvey

I would suspect the sender unit in the back of the thermostat housing or the wire Lucar terminal at the same place? The conductor can start break away leaving only a few strands connected ! This has happen to me in the past.

Bruce.

 

Link to post
Share on other sites
  • 2 weeks later...

sudden change to low reading temp gauge has happened to me twice now in 9 years.  On both occasions caused by sensor going faulty, confirmed by resistance measurements taken against increasing water temp .  In both cases resistance fell until about 75 degC was reached and then increased as temp continued to rise.  Simple and inexpensive fix!!  Gauge now reading dead centre with thermostat housing at 92degC, using an 82degC thermostat for reasonable heating in the winter.  No mechanical fan just a rarely used manually-operated Kenlowe in front of the radiator, for the occasional need in certain traffic situations.

Link to post
Share on other sites
  • 1 month later...

Just to bring this thread to a conclusion, it was the temperature sender that was at fault. Fortunately I had one in my spares.

Sorry for the late response and many thanks to all that posted with your advice.

Link to post
Share on other sites

Hi William 

It is a black one, not sure of it’s age though as I bought a job lot of spares about 10 years ago. The new one is a bit shorter than the old one. Temperature gauge now reading in the middle like the old use to do.

Link to post
Share on other sites

I bought mine from a local general car parts shop, once I knew the correct type (number). I checked the resistance before installing and it is fine. 

Waldi

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.