temperature dilema

[Don McLean]

Understood, Graham, but thought you had to drain system to install new sensor. Haynes manual advises this, and wouldn't the system drain anyway when you remove sensor?

[Staggard]

Understood, Graham, but thought you had to drain system to install new sensor. Haynes manual advises this, and wouldn't the system drain anyway when you remove sensor?

You just unscrew the old sensor put your finger over the hole pick up the new one and screw it stright back in. at the most you loose an eggcup full. Anyway its high up on the back of the head so (worst case)you would not loose a lot. Also providing the caps are in place it can only dribble out if air can't get in coolant can't rush out (creates a vacum) Graham PS Haynes says there,s a lot of things you have to do, alternator for one

[Don McLean]

Great tip Graham. As ever with good tips, it seems obvious when you know how!
Thanks again for everybody's help.
Don

[DJT]

You just unscrew the old sensor put your finger over the hole pick up the new one and screw it stright back in. at the most you loose an eggcup full. Anyway its high up on the back of the head so (worst case)you would not loose a lot. Also providing the caps are in place it can only dribble out if air can't get in coolant can't rush out (creates a vacum) Graham PS Haynes says there,s a lot of things you have to do, alternator for one

As long as you don't cross-thread the new sensor when fitting it. That turns a 5 minute job into a 2 hour one. No need to ask how I know..........

[big e]

I am led to believe that some temp senders do give a higher reading. Apparently triumph or bl standardized the use of senders and used one that was roughly correct spec. Its these that can cause a higher reading. I think its the ones with a black end give a reading in the centre of the gauge whereas the white ended ones show a higher reading.

[TopDown Ed]

You just unscrew the old sensor put your finger over the hole pick up the new one and screw it stright back in. at the most you loose an eggcup full. Anyway its high up on the back of the head so (worst case)you would not loose a lot. Also providing the caps are in place it can only dribble out if air can't get in coolant can't rush out (creates a vacum) Graham PS Haynes says there,s a lot of things you have to do, alternator for one

I did it this way and it seemed to work, with little loss of water. However, I also got a higher temp reading with the new sensor, came as a big surprise/worry. Instead of running nicely at the middle of the gauge, I suddenly seemed to have a hot engine. However, the temp stays at the same level (ie doesn't seem to get any hotter) so I relaxed. The question is, was my old sensor showing a (wrong) low reading, or is my new sensor incorrect? I know I could get an accurate actual temp gauge, but, hey.....

[Staggard]

I did it this way and it seemed to work, with little loss of water. However, I also got a higher temp reading with the new sensor, came as a big surprise/worry. Instead of running nicely at the middle of the gauge, I suddenly seemed to have a hot engine. However, the temp stays at the same level (ie doesn't seem to get any hotter) so I relaxed. The question is, was my old sensor showing a (wrong) low reading, or is my new sensor incorrect? I know I could get an accurate actual temp gauge, but, hey.....

If you go on to LD's website as per posting 12 DJT it will explain about miss matched temp senders

[richardthestag]

I am led to believe that some temp senders do give a higher reading. Apparently triumph or bl standardized the use of senders and used one that was roughly correct spec. Its these that can cause a higher reading. I think its the ones with a black end give a reading in the centre of the gauge whereas the white ended ones show a higher reading.

Spot on. I had a thoroughly miserable trip across Europe with a white sender fitted. It went in the day before i left and i didn't notice owt wrong until the ambient temperature rose. Slowing for telepaege caused the needle to surge into the red causing minor panic, lifted bonnets, heater on full etc etc. only once the brown smell had subsided i noticed that the engine didn't seem any hotter than usual. I proceeded after checking coolant level and for bubbles when running etc

still a high speed run with the temp needle on the edge of the red, did not make for an enjoyable trip.

It was only when i got home that local specialist was able to get an infrared thermometer on it and see nowt but normal while the gauge was showing red. After a quick check that the voltage regulator was still earthed it had to be the temp sender. The old unit went back in and it was then that i noticed the different colour insulation.

Order was restored once i dispatched the newer white insulated sender into the middle of a field with my trusty tennis racket.