Thread: TM2 Average Temperature Readings

A pressurised coolant system will get much hotter than 100 degrees.

The TM2 cannot measure the exact temperature of the head as it is mounted externally so the temperature it displays at the sensor is a measure of a number of items but mainly head temperature moderated by other factors - eg heat from the exhaust if nearby making it higher or if in the airflow from the fan a bit lower. The actual temperature displayed is almost irrelevant by itself that is why the instructions do not have an indicative temperature - if I remember correctly they say to drive your vehicle so it gets to operating temperature, note the temperature on the TM2 display and set the alarm at 15 higher.

On my TM2 on my V8, the temp stays at 71 when the engine is running normally and water is 85 but clearly the internal temp of the head will by much hotter. My water temp stays relatively constant where the TM2 can go up to 82 on a hot day idling in traffic - the coolant temp does not change as the thermostat is opening and allowing more coolant through the engine - this is not to say the engine is not actually getting hotting. If you had an oil temp gauge you would most likely find it would be getting hotter as well as the TM2.

So don't worry too much about the temp readout in itself but note the changes in temp - set the TM2 to about 15 hotter than the every day operating temp showing on the TM2.

Garry

You can obviously test the sender and gauge to make sure they are doing what they are supposed to do - however as a general statement if the cooling system is full and not loosing water and you are satisfied that the gauge and sender are OK you could assume the cooling system is Ok - the issue you initially raised indicates to me that your system is most likely OK and the water is taking the heat away as it should. If you lost a bit of coolant I can almost guarantee that in the same situation that you decribed then the coolant temp would rise.

My Freelander temp gauge always sits on midway - no matter what the outside temp and load on the engine. All of a sudden I noticed the gauge getting a little hotter - just a little - I ignored it - later it started getting higher - there was a small split in a hose that only allowed coolant to escape when hot - so the gauge will move with reduced cooling capacity.

So - as long as you are not loosing fluid, there is no oil in your coolant, nothing is dripping, and you system is not being pressurised (bubbled in the coolant) and the gauge stays on normal (with full coolant levels), particularly when working hard then you do not have an issue.

But like you - I always watch what the TM2 is doing - was really surprised how much it rises when stopped for long periods in heavy traffic (lack of airflow) - but the coolant stays on normal and does not rise with the TM2.

Good luck with it.

Garry