Thread: Engine Watchdog Tm2

Originally Posted by Phoenix

what good is a sensor that measures the temp of the outside of an engine anyway?

They work fine on the outside of the block because cast iron / aluminium are such good conductors of heat. If you were to lose coolant or suffer any other form of cooling system malfunction the block's temperature would rise fairly quickly and these devices measure the temperature every second.

The temperature on the outside of the engine block's coolant jacket is obviously lower than the coolant temperature itself so you pre-set the warning accordingly (just a few degrees above your max figure normally obtained).

It's best to mount the sensor sensibly, there's no point hooking it up to a lifting eye or something else 'thin' and away from the heat source or in strong air flow, so close to the block wall on an available bolt or epoxied on is best in my opinion.

I've got mine fitted to the 110 and I love it, it's real assurance to see it working. Mine is a 4BD1 Isuzu and sits between 69 degrees C and 73 degrees C depending on whether its a 20 degree day or a 45 degree day. I've got the audible alarm set at 75 degrees.

The only slight downside with this device is that when you turn the engine off, the block temperature increases due to the heat soak from the coolant no longer circulating. Obviously you fit the device on an ignition switch controlled circuit so it won't be going off when you leave the car. But if you re-start two minutes later, then it's likely that the alarm will sound for 30 seconds or so until the coolant starts circulating again and cools the block once again. Where I've got my sensor mounted it gets to 76 degrees when the engine is stopped and the alarm is set to activate at 75 degrees, so it goes off for a short while (which is re-assuring to know its working). This can be avoided by setting the alarm threshold higher, but I prefer to have it more sensitive.

Over time this device will let you know of slow acting cooling system degradation, such as radiator blockage (internal or external), radiator fin corrosion, water pump impeller corrosion, etc. as the running temperature will increase over the years. Mine has a completely re-vamped cooling system, so it'll be interesting to see if it still runs at 69 degrees in five years time!

I have no vested interest in this device other than being a happy customer.

Hope this helps,

Jon

I've got one of these but I use it to monitor the auto gearbox temp. Call me paranoid but after frying one auto box you get that way after paying the bill. The sensor bolts into a spare tapped hole on the passenger side of the box. Normally runs at about 65 to 70 deg but can go up to 85 when towing.

Russell