Bongo Fury

Now I've searched all about the TM2 and Haydon alarms but just ended up in a culdesac of people arguing about why no one had published the temperatures that they had experienced with a TM2, with no real results.

My question is: What is the max temperature of the cylinder head before problems arise? (2.5TD)

I drove up a hellishly steep hill yesterday - fast as I could - with a run up! Ended up charging up most of it in 1st at high revs)

The TM2 showed the temp climbing fast (sits in the early 90's all of the time normally) and it hit 100 which set it's alarm off (the (Haydon'd) needle was just before the end of the temp guage). I got to the top of the hill moments later - the alarm continued for about 30 seconds, then the temperature plummeted back to the mid 90's in what seemed like 10 seconds!

At no time did my Haydon alarm go off (set at 4.5), or my low coolant alarm.

I'm assuming the fan kicked in at the last moment, and that 100 is fine, seeing that the coolant should tolerate more than that before boiling.

I suffered no boiling, or coolant loss. Everything seems fine .

(My vehicle has historically .i.e. before me, had a new head, solicone hoses, radiator etc when a previous owner pushed his luck - hence it came with all three alarms)

Hi
Where is the TM2 sensor?
What do you mean about the needle moving, and a setting of 4.5?...it sounds like you are talking of a Mason modification on the original Mazda temperature gauge????
Cheers
Helen

QUOTE :- At no time did my Haydon alarm go off (set at 4.5)

That's not a haydn ALARM..Sounds as though you have a Mason ALARM....That alarm makes the temp gauge more sensitive so it moving up towards the HOT can be expected.

The acceptable temp range for the TM-2 depends on where the temp sensor is bolted to the cylinder head...For some years now I have recommended a position on the back of the cylinder head which is easy for the DIY fitter to access and if enough peeps give feedback a "average" set of figures could be compiled.....However some have fitted the sensors in alternative positions which tends to "muddy" the waters....Also no two coolings systems will be exactly the same and slightly differant readings will result.

IF your sensor is fitted to the back of the cylinder head....expect every day running to be 85 to 95C.....towing and thrashing up hills...95 to 105C.

Your Low Coolant Alarm would have no reason to go off as it has nothing to do with temps....just coolant loss.

Sounds as though your system is good but normal running temps a little high.

the thing to do whatever model of alarm you have is to run up to hot on the drive until the cooling fans come on, then note the top temp, then you know what the top safe operating temp is for YOUR MOTOR when your out on the road.

Thanks all - yep - I got the names wrong. I have the one that alters the temperature needle - removes the dead spot - it has a small box with a blue dial set at 4.5 .

My TM2 sensor is on the head at the back as recommended.

I'll do the parked warm up test today .

Thanks again

Northern Bongolow wrote:the thing to do whatever model of alarm you have is to run up to hot on the drive until the cooling fans come on, then note the top temp, then you know what the top safe operating temp is for YOUR MOTOR when your out on the road.

One question - doesn't that just tell me at what temperature my fan thermostat is set? - which should be a constant...

Dodgey wrote:

Northern Bongolow wrote:the thing to do whatever model of alarm you have is to run up to hot on the drive until the cooling fans come on, then note the top temp, then you know what the top safe operating temp is for YOUR MOTOR when your out on the road.

One question - doesn't that just tell me at what temperature my fan thermostat is set? - which should be a constant...

Yep - almost. And that will (should) happen when coolant temperature reaches 96/97 degC.
The fans are switched on via the ECU, which gets the temperature signal from the engine sensor mounted in the head (drivers side).