After blowing a head gasket and the factory gauge didn't show anything until the engine had already lost power, I am looking to improve the temperature monitoring ability.

I was already thinking of installing an oil temperature gauge to test if a sump guard really restricts airflow too much for the auto like people say. Apparently with autos when a sump guard is fitted an oil cooler is required, that is what UK people say and they are in a lot cooler environment. My mini already had a sump guard fitted and the transmission had damage due to low oil pressure so I don't want that to happen again.

I am now thinking that the best solution (without drilling a hole in the transmission cover) might be to install something like an Engine Watchdog (http://enginewatchdog.com/index.html) or Engine Guard (https://engineguard.com.au) using the bolt on sensors.


I think I would go with the Watchdog as it looks a lot better, the Engine Guard looks like a cheap thing with the side cable entry etc.

I would probably bolt one sensor on a front cover bolt or the diff housing and the other on the head somewhere, maybe the long head stud.

Does this sound like a good idea and is this going to be accurate enough to tell anything especially the oil temperature?

I could install separate gauges but that is another thing to look at as well as more stuff in an already full air conditioned Rover engine bay and dash.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

May not be relevant, but I have fitted the Engine Guard to my 2017 Mazda BT50 for similar as the standard gauges act the same way, let you know too late. I just bolted the engine one to a bolt on the water pump that had enough thread and one to the gearbox in a similar fashion, the biggest problem with the mini will be what to do with the excess wire that is supplied. I am very happy with mine, there are plenty of settings to achieve what you want and I had good communication with the owner/maker when I needed info. Been in the car for 3 years now, normally tow a caravan. Never had any problems.

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1974 Leyland Clubman
Lots of good machines

Of all the things I have lost, I miss my mind the most.

I am pretty sure both said the sensor wires can be shortened.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

Try a hand held IR temperature gun to learn what is NORMAL for the engine and sump temps.
(also good for brakes and bearings)
I also have one to check the CVT temp of our Forester when we tow our small van.
Good luck Dave D.

Are you going to note the temps with and without a sump guard fitted? I would be interested to see if there is much difference without the aircooling effect.

Yes, that is the plan. If the temps go up much then I will have to remove the sump guard, there is no space for an oil cooler. The trips I really need the sump guard are also the ones that will be long distances at high speeds.

I am going to order the engine watchdog, I can always find another use for it but I expect it will work well for the mini.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I have a couple of Engine Watch Dogs on my competition cars....excellent product

I bought the engine watchdog tm4 twin and have now installed it. The mounting holes even matched the rover switch panel that I removed to install this, the switch panel didn't do anything anymore.

Currently it is set to the default 100° alarm setting, I think I might want to lower the transmission alarm a bit but I will see what it runs at.

I have also wired it up to the oil pressure switch so it will sound the alarm if the light comes on, like when the auto selector seal pops out







I also installed the clock at the same time, I think I will slowly look for another one without led illumination as it is by far the brightest thing and cool white.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

The problem I am having is that when I am moving it reads only about 50° but if I sit still it climbs up slowly to the correct reading of 80°+

I had read airflow would mess with the sensors but didn't think it would be this much. I thought maybe the transmission would have the problem but not the head.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I had this same problem with my fuel gauge. Turned out to be the voltage stabiliser and road vibration. An electronic one fixed it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

It is the reading on the engine watchdog so unless it is faulty internally it won't be it. I assume it regulates the voltage properly internally.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I thought there would be enough thermal mass there even on top of the head nut but I will try move them. I am thinking to the short steady bracket bolt, I will sort out the engine temp before finding a spot on the transmission. This is the response from the manufacturer:

"Generally once the sensor is mounted hard to an engine it just becomes a very small piece of metal attached to a huge mass of metal and air passing over the sensor has very little affect. If in your case for some reason it is, I would suggest moving the sensor out of the air flow and towards the back of the engine. Lots of people prefer the back of the engine as they feel it gives a more accurate indication, however I have personally not noticed any significant difference. If you move the sensor you just need to re-establish the new normal and reset the alarm temperature to suit the new location. Below is a generic explanation as to why moving the sensor to various parts of the engine usually makes very little difference to the alarm point."

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I had the same air flow cooling problem when I fitted a home made LM35 oil temp sensor to the oil outlet pipe of my mini. After wrapping it in layers of tape held on with multiple cable ties it finally agrees with the temperature gun readings ......... hence, why not just believe the temperature gun.
I'm not sure if the auto mini has anywhere to "wrap" the sensor to get an accurate temperature reading. Maybe the oil filter canister? If you lie the sensor metal washer flat on the surface and then wrap the canister in multiple layers of wide insulation tape you might get a real oil temp reading.
The response from the manufacturer includes the phrase "new normal" rather than temperature. Does this mean that it is measuring a temperature other than the temperature inside the gearbox?
Good luck. Dave D

It is reading the temperature of what it is attached to such as one of their examples a rocker cover bolt. If it was attached to something like that I think it would be a very different reading to the actual head/coolant temperature and would take a lot longer to show a fault (unlike what sellers of products like this say). It will give an indication of the "Normal" temperature but to me that would be pointless, if coolant was lost I think a lot of damage would be done before something that far away became a high temperature.

I have moved the engine sensor to one of the bolts for the heater fitting and it is on average reading higher but I think this won't be a good indicator as the head temperature is isolated by a gasket. I will drive it for a couple of days to see what it reads.

For the transmission sensor I haven't moved it yet until I can work out a method with the engine sensor. Once I find a better location for the sensors I am thinking of putting thermal paste under them to improve stability.

This is also an interesting thing for me to work out as I had planned on "bolting" a temperature sensor to a different car (not a mini) to control an electric fan.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

As I have indicated in other threads it blew another head gasket. The factory gauge moved above 3/4 (3/4 seems to be "normal") a few times however the engine watchdog only showed about 5° above normal meaning 90° (remember this isn't the coolant temperature).

Probably the weirdest part is that I have two fan switches and neither of them seem to have activated. one is the factory/dealer one in a thermostat sandwich plate and the other is in the bottom tank as I am using a later radiator. It had been loosing coolant when I checked once cool but the heater always worked and everything seemed normal otherwise.

The head gasket failed between 2,3 and the cooling system.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis