If you have a TM-2 gauge fitted PLEASE read this

[haydn callow]

I am trying to get some facts together and if you have a TM-2 fitted you could be of great help if you can answer the following.

Exactly where have you bolted the sensor ? (photo would be good)
What is the approx average readout you see ?
What is the highest readout ever...and under what circumstances ?
What temp have you set it to alarm at ?
What is the reading when the Bongo gauge first reaches "normal" 11 o'clock ?
Was the Bongo gauge still reading normal when the highest ever reading (above) was observed ?
Have you ever reached 110 oC ?

Answers to these questions will be of great help to me and may benifit others in the long term.

VERY MANY THANKS for your time.

[helen&tony]

Hi Haydn
i have sent you some of the details, but I'll post the rest here.
I had the sensor on the first rocker cover bolt passenger side, and have recently decided to monitor elsewhere after about 10 months of checking. The readings were lower than I thought could be expected, as I feel it was getting cooling off the alternator fan, or , perhaps, blown upwards when forward speed was fast enough, from the scavenger fan aperture....my thinking will be apparent from the results.
The readings i got were:-
The gauge starting to register in the first third of the gauge (spring and autumn)....about English high summer temperatures....TM2 around 43- 50 Deg. normally 5- 6 Km.
Normal running temp on gauge, and having driven around 12-14Km...54- 63 Deg.
Slowing in town...18Km...71-75 Deg.
By this time, insufficient forward speed to get airflow from the scavenger aperture, and picking up turbo heat.
After town, back down to 60- 63 Deg. cruising at 80 Kph
Driving in the Balkan foothills up 5 Km. hills, around 69 Deg
I haven't been into the mountains proper since fitting the gauge, but to get to a friend's house, its down to "L" gear....i'll soon give it a go.
Park in town, and return in 10 minutes, gauge at 95 Deg. ....alarm set at 92....drive away, and in 2-4 minutes gauge down to 73 Deg. Drive out of town, and back to 63 Deg. Park for longer periods, and the engine temp will cool on TM2....say a half hour.
Temperatures over here are currently 38 Deg with no apparent problems with the Bongo system
The gauge has never risen dramatically to 100 degrees, even when the radiator went (it had been oozing for a while), as the water did not entirely disappear from the header/ degasser tank.
One VERY interesting twist, is that driving in the snow last winter (the CLEARED snow was over 1 foot deep), the gauge went up to 71 degrees where I would normally expect to read around 60, as I was driving slow (the snow itself was 2 1/2 - 3 feet before clearing), also I expect the scavenger fan aperture was scooping up snow. In these conditions the car had to be cleared of snow and ice round the radiator daily, and temperatures were down to the worst day at minus 22, when the fuel froze in several diesel cars.
The TM2 also reads down to about minus 40 when you turn it on....on average, mine was down to minus 12....starting no problem, even with a knackered battery.
Hope the figures are useful....will send more whenI get the new readings now the sensor is moved
Cheers
Helen

[lev8]

having done 8000 km in 4 months
1. Middle rocker cover bolt, drivers side
2. City 94C, m'way 88C
3. 102 on restarting after 5 min stop, from cruising at 110KPH
4. 100
5. never noticed
6. ditto, the alarm and display had my total attention
7. NO

my temp really jumps as I slow from a fast cruise >100KPH, I just hate roundabouts followed by red lights It seems as if the thermostat lags the fall in engine revs and causes the temp rise becuase the coolant flow has decreased

[haydn callow]

Many thanks....exactly the info I'm after.

[haydn callow]

Done a bit of temp takeing.
These are measurments taken after 20mins ticking over and results may well change after a long run and everything is heatsoaked.
There is a 8 to 10 degree differance between a cylinder head (the knurled rusty ones) and the rocker cover bolts.
i.e. 80 oC cyl bolt = 72 oC rocker bolt


There is a 5 degree differance between the exaust side and the inlet side.

The tapped "holes above the exaust manifold read half way between a head bolt and a rocker bolt.

This was done with a digital infer red thermometer and the TM-2 gave the same readings within +/- 2 degrees

I will have another go after our next big run.
However. it may be that a 110 degree switch under a rocker bolt may be to high.

This is what the testing is for.

[Lewy]

I'm very pleased with the TM2 - would be interested to compare notes with other people though as it peaked today on a long 20% upward incline in Dartmoor and got up to 99 degrees - Mason alarm also started to pip at the very top of the incline - its set to 5 and the needle was just under the hot part of the gauge. I pulled over and checked the coolant - nothing bubbling or loss of fluid - rest of the journey no problems. I've noticed the Mason adjusted temp gauge flucuating as it gets hoter on normal runs - this then brings the temp down on the TM2 from a usual 92/94 often to 88/90 on A roads.

So the answers to questions are:

1: 90 - 94 on normal roads rising to 95 /96 on steepish inclines.
Highest readout TODAY on long 20% incline in Dartmoor got to 99 I think
Temp has been set to 97 but might now change it to 99
I think about 60ish for it to be at normal Mason 1 O'clock - but might be wrong about that - will check and repost
Bongo gauge was just under hot zone at 99%
No not gone beyond 99oC

I've fitted my sensor on rocker bolt underneath the spacer directly onto the metal third bolt in from the middle on the drivers side.

[bongo bri]

[quote="haydn callow"]I am trying to get some facts together and if you have a TM-2 fitted you could be of great help if you can answer the following.


Hi
I have mine drivers side front rocker bolt with a universal engine fan switch e-bay number 260187268747 (90degrees C )
The switch is wired through a 40amp relay to the Fast speed fan wires from the junctions near rad. The Feed is taken from main battery through 30 amp fuse then split to 2 15 amp for each fan. The feed for temp sensor on rocker is from ignition side so it only works with ignition on.
When temp reaches 90 c the fans come on and stay on as the engine will not cool to 78 c to turn off again , so I have fitted a manual switch to turn off sensor at 85c which is my normal running temp. I would like to fit 100c sensor as this would cut off nearer 85C but I am thinking by the time it reaches 100c it might be too late. Hope this makes sense. Basicly I dont trust ecu for turning fans on.
Keep up the good work
Brian

[Lewy]

Brian - I am very interested in how to encourage the rad fans to come on at full speed before the sensor which seems to switch them on only at very high temperatures.

Does your new 90oc fitted switch over-ride the original water temp sensor that is screwed into the head?

I'd like to fit a manual switch so I could activate the fans during long ascents or when I see the TM2 getting too high - but I have very little auto elec knowledge any chance of a dunce's guide to your solution? Or anyone else for that matter? Haydn are you working on something?

[bongo bri]

Brian - I am very interested in how to encourage the rad fans to come on at full speed before the sensor which seems to switch them on only at very high temperatures.

Does your new 90oc fitted switch over-ride the original water temp sensor that is screwed into the head?

I'd like to fit a manual switch so I could activate the fans during long ascents or when I see the TM2 getting too high - but I have very little auto elec knowledge any chance of a dunce's guide to your solution? Or anyone else for that matter? Haydn are you working on something?

Hi Lewy, The set up with 90c sensor doesnt effect original setup just makes fan come on at 90c.bearing in mind this may not be the exact head temp, it seems to be ok. Normal running temp is about 85c 87c I would ideally like a 95c but cant find one as this would probably turn back on nearer to 85c. If my TM2 rises to 90c the fans come on but I turn them off with a switch when the temp comes down to 85c and should set TM2 to 92c ish to remind me to turn them back on.
None of this interferes with original set up, my switch is just for new sensor.
I think Haydn is working on something a bit more technical, I would like his comments first and not be the blind leading the blind as it were.
As the fans draw a large amount of amps I have used a relay and have checked that relay fuses etc dont get hot.

Cheers Brian

[Coolhand]

1. Second threaded hole on the cylinderhead passenger side.
2. 92 oC Urban, 97 oC Motorway (both rise about 2 oC on a hot day)
3. 114 oC warm day on a climb
4. 116 oC
5. 67 oC
6. Yes
7. Yes

[haydn callow]

Interesting...it would seem the standard Bongo gauge dosn't move from it's 11 0'clock position from about 55 0'c all the way up to 114 0'c.....No wonder when the gauge does eventually move it is often too late.
Also I reckon the cylinder head bolts are a couple of degrees higher than the place you have your sensor.

Has anyone recorded a higher Max temp than Coolhand?? without overheating ??

I belive the boiling point of the coolant is about 122 0'c with a 1.1 bar cap.
Can anyone confirm that ??

[2sticks]

At 210 kPa (Absolute), water boils at 121.78 degrees Celcius.

A good quality antifreeze should raise this by 8 - 10 degrees.

Some time ago, I fitted a pressure gauge to the cooling system
and with the correct levels in the tank, and with normal driving
conditions, the gauge pressure did not exceed 40 - 50 kPa.

At this pressure (150 kPa Absolute), boiling point is 111.37 degrees
Celcius, plus 8 to 10 degrees for the antifreeze.

[Simon Jones]

1) Front rocker cover bolt on inlet manifold side
2) 87 - 89 based on 65 - 70 mph on Poland trip
3) 95 having climbed to the top of a very big hill (actually a volcano!). Also got to 96 when left with engine off for 10 mins at motorway services
4) Currently 96, but may increase once I get a proper feeling on what is 'normal'
5) Not 100% sure - as running with Mason Alarm, but I'd say about 80 ish would be up to normal temp
6) Interesting observation when using the TM2 & Mason Alarm: after initial warm up, the water temp 'leads' the engine temp. The Mason Alarm shows a noticable deviation in normal use which I believe would correspond with the thermostat opening & closing. The water temp goes up to the point where it opens, then about 1 - 2 minutes later the engine temp goes up approx 2 degrees. When the water temp drops back down (you can see the needle move) then approx 2 mins later the the TM2 drops back down. My conclusion is that this shows the coolant is correctly taking the heat away from the block at a faster rate than the metal can heat up so there is a natural delay. This is the not the way round I would have expected. Can anyone confirm this observation?
7) No - would probably have cooked the engine by then

[haydn callow]

Thiis all good feedback and I will print it all off and try and make some conclusions. I will leave it a couple more weeks in case there is more to come.
Thanks in the meantime

[2sticks]

I don't have a TM2, but I do have 3 thermocouples fitted, 1 on the centre
8 mm thread on the passenger side, and 1 on the forward rocker cover bolt
on the drivers side. The third one is on the gearbox.

I use 2 accurate hand held digital thermometers to monitor the temperatures
simply for testing purposes, this is usually when I do a coolant change, or a
checkup when I tow the caravan on a hot day.

My results are very similar to COOLHAND'S and this seems to be about right to
me considering modern diesels are designed to run as close as possible to
100 deg. C.

As I can measure both thermocouples simultaneously, I have experienced the
following temperatures while driving under various conditions.

After an extended tickover, the driver side sensor will register around 88 - 92
deg. C. The passenger side sensor will measure 1 or 1.5 degrees higher than
this. The passenger side sensor is very close to the exhaust valves, but very
little work is being done, so this makes sense.

Normal driving at no more than 50 MPH, the driver side sensor may increase
to 90 - 94 deg. C but remains consistant. The passenger side sensor will
normally read 3 or 4 degrees higher than this which makes sense to me as
more work is being done.

Towing my small caravan on a long uphill drag at 60 MPH, the driver side
sensor will increase to 92 - 96 deg C. but the passenger side sensor will show
at least 116 degrees and I have seen it go up to 118 deg C. This is no more
than I would expect given it's position, which is very close to hard working
exhaust valves.

When I get back to level roads again, the driver side sensor takes about 4 to 5
minutes to return to 90 - 94 degrees C. again, but the passenger side sensor
may take up to 15 minutes to return to normal temperature which is around
100 degrees C. while towing the caravan at a leisurely pace.

I do have Haydn's low level alarm fitted, and a Mason temperature alarm also.

Sorry for the long winded reply, but I thought it may be of some use.