Does the M13A engine have an oil temp sensor?

Unless you know what the oil temperature should be and what the safe limits are won't you just be giving yourself another thing to worry about? It's the same reason that modern temperature gauges are calibrated to sit exactly the middle over a wide range of running temperatures.
90% of drivers have no concept of warming up an engine and yet even the most neglected modern cars easily clock up hundreds of thousands of miles without any signs of engine wear. A moderately well maintained Jimny will be a pile of brown rust long before the wearing parts of the engine go out of tolerance.

Our Gen 4 Jimny has a little blue light on the dash that goes out after a short time when the vehicle is driven from cold.

l assume this is an indication of when it's okay to use all the performance, although we never thrash the Jimny anyway. lt's never been near the red line! Not that l think it will do any harm, which it won't, but there seems little point.

The blue cold engine light is an evolution of the temperature gauge, because manufacturers have realised most drivers don't understand how to read a temperature gauge.
If you never drive your Jimny hard then it is fairly arbitrary. I don't redline mine until it's warm.

If you have an automatic transmission I can see some benefits in having a temperature gauge for the transmission oil as it gives you a good indication of how hard you are making it work beyond the little light on the dashboard for over temperature and with a guage you can decide to back off a bit especially if you are towing a trailer. Generally though one for engine oil is a bit unnecessary.

Torque & SZ Viewer can extract some live data for the OBD2 & non-OBD2 M13As, respectively. All you need is an ELM327 w/ the PIC18F25K80 chip.


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Oil and water are likely to warm up at similar rates. Ultimately water will likely top out at 90deg.C with oil being higher. When engine testing at Rover we took water up to 105deg.C and sump oil to 120deg.C. Oil will reach 175deg.C before it begins to break down. Forget the oil temp. gauge for the engine and rely on water temp. Yes, the Gen.4 has a little blue light that goes out after about 1Km but the engine hasn't quite reached operating temp. Remember, the engine should reach operating temp if all is well but the radiator shouldn't! It is there to cool the water. Hot water in, cooler water out.
A temp. gauge on an auto box is usually only necessary if you regularly tow heavy loads in high ambient temperatures up steep hills ie you are using high power in low gear. If this is the case, then consider a transmission oil cooler allied to a thermostat.

Roger