Triumph TR7 Heating Gauge

[swordfishdani1960]

Can anybody say is there a norman temperate setting as per gauge in car ,GOES FROM 1/4 WAY TO 3/4 ON THE GAUGE IS THIS SAFE theres no water loss, expansion tank gets filled up ,with pressure ,and water once cooled down it returns back into to engine
i replaced my temperature sensor before this happened ,just wondering if temperature sensor is sensitive or different kind .never have i had the temp gauge above 1/4 at any time thanks all

[saabfast]

They generally run between just over 1/4 to just under 1/2 with the standard cooling system and fan. I have an electric fan set to control between those points.
What is your cooling system, standard or modified with electric fan etc?
Have you got the correct thermostat (the one with the 'foot' on the bottom)?

[Beans]

The temperature should be constant and somewhere between the ¼ and ½ mark on the gauge.
If the temperature moves up and down there's something wrong with your fan assembly or thermostat.
Are you using an electric fan? If so, it is set incorrect

[Hasbeen]

As beans says, what thermostat do you have in the thing? My 4.6L 8 used to run up to 3/4 while warming up from cold or cool, before the thermostat on it would open. It is not a special thermostat like the 7, but a new one fixed the problem.

My 7 sits rock steady on half a needle above 1/4 on the gauge. This is with after market air-conditioning going flat out on 100F + days, or frosty mornings with the heater going.

It was just OK before I fitted a new thermo fan a few years back & spot on since. I was amazed at the increase in noise from the new fan, due to the very much greater amount of air it was moving.

I don't know if you can change the oil in our thermo fan, you could in a Toyota Cressida. I did it a couple of times in mine over the 376,000 kilometres it did. It would start to run hotter a couple of times, & new oil in the thermo fan fixed it each time.

Hasbeen

[busheytrader]

Hi,

I wouldn't assume that a new replacement part can't be faulty. It can. At least these sender units are relatively cheap.

It's also possible to be sold a part that fits our vehicles but the spec is for a different one. This happened to me at a motor factors. The cooling system worked fine, but "normal" moved further up the gauge.

If your strange readings only occurred after fitting a new sender, what made you remove the previous one? Can you retro fit it? Do you have a multimeter to compare readings on the old and new?

When I had a 2.0L engine with the factory fitted belt driven viscous fan the needle spent 100% of its time just past the 1/4 mark like Hasbeen. It only passed this when the water pump started leaking, so your experience would scare the cr4p out of meespecually with the engines reputation for warping cylinder heads.

As per Hasbeen, the viscous fan coupling IIRC is 100% sealed unit and the thermostat must be an original spec with the "foot" on it to prevent uneven temperatures across the engine.

[FI Spyder]

The reason the "Triumph foot" has been mentioned a few times is because the foot blocks off the bypass when open so all of the coolant gets directed through radiator. Without it only 50% (give or take) goes through the radiator so even if everything is up to snuff, you would only be getting half of the cooling available. The incorrect thermostats are listed as fitting the TR7 (and TR6s) so be aware of it. The heat sensor is a resistor that puts a resistance in the circuit to decide where the needle will sit so if it is "out of spec" this can change as will any resistance in the circuit such as corroded connections or wiring imperfections. These things will likely not make the gauge appreciably go up and down while driving, it usually is pretty steady. Any up and down while driving likely would have other causes like sensor (they are cheap). The thing to be aware of is changing a sensor (or gauge at other end) might knock off corrosion at connectors there by changing the problem with the resultant incorrect assumption "oh, that fixed it". The first thing to do with these things (like this or clock circuits for example) is to make sure connections are clean with contact cleaner and brushing (if possible).

[swordfishdani1960]

Hi thanks ,yea its an electric fan its set at number 4 on the thermostat that controls the fan, it runs ok as far as the built in thermostat ,it was bought from Robsport inter
fitted about 8 years ago its always been fine , i feel if my engine is running hot with the gauge at 3/4 is it overheating , cars was unused for 3 years ,was in the garage so this has only happened after 3 years in the garage ,engine was flushed rad cleaned ,new oil ext ,well i change oil and filter every 3 months ,it concerning

[swordfishdani1960]

I replaced the sensor because i had no reading at the temperature gauge
so new one fixed that , from Ropsport inter after 10 mims a runing the car
the gauge reads 1/2 and then moves up ,i haven't run the car by 3/4 to see
what .or if goes wrong

[busheytrader]

I'd whip out the thermostat, place it in a glass and pour boiling water over it to test if it's opening properly if at all.

I've had 2 cars where the thermostat failed after 100,000 miles. A Mk3 Gti and a Mk3 MX5. However both failed in the open position, thus overcooling the engine. Both suppliers told me that they were designed not to fail in the closed position.

[swordfishdani1960]

Thanks all who helped in find a solution Temperture gauge reading high
fist i checked in car reading on gauge with the ignition on, but not running
from cold ,the gauge read a 1/4 moved so fast so this lead me to believe
that the sensor i fitted was reading high ,which meant the high temperature
when runing ,so i put the 'faulty' one back in ,and its now back to what it was 3 years ago just below 1/4 on gauge so it may have been a bad cable conection at the time
thats all

[busheytrader]

Sounds good. If you only have an electric fan, ran the car up to temperature and drove in town traffic or idling, would the gauge Register much more than 1/4 before the electric fan cut in?

[swordfishdani1960]

Well got my new sender unit its in the car ,and it reads the same as other one hight
Rob sport supplied me with new one ,said the problem would be with the voltage regulator, ie,, delay unit low fuel level light, thats the part behind steering wheel under the bonet with the four wires going in to it ,said that would make the heater gauge hight
I've checked the circuit diagram its not even in it ,as part of the sender sensor .the only thing left is to change thermistat any body shed an light on this ,thanks

[swordfishdani1960]

Hi ,yes i have fitted electric fan with thermostat switches on 10 mins runing the gauge is at 1/4 the other thermistat with the foot on it ,do you have a photo , you said foot on it
so if i ask rimmer bros to send one with a foot on ,they will no what i mean

[Beans]

This is what you should be looking for in a TR7 (no idea for the V8 variant) ...

[swordfishdani1960]

What i can see theres 2 types of thermistat showing
GTS 101 OPENS AT 82 DEGREES
GTS 108 OPENS AT 88 DEGREES
THEY BOTH LOOK THE SAME WHICH 1