Water tem^p gauge problems in Mauritania
 

I am currently in Nouakchott inb Mauritania and I have a series 3, 1983, petrol bearing. The gauge shows the needle on red most of the time although I hazve just crossed the Sahara in 3 days and the engine, radiator, hoses are fine and you can touch them even after 6 hours of driving in sand in 40 C + / I have already changed the water pump (new), the wx filled thermostat hqs been thrown away, the radiator was striiped ane re-soldered in Nouadhibou, the coolant circulates, the brakes are fine, the engine is running like a gem, the electric thermostat by the engine block is new (managed to find one yesterday), waterways are clear, water circulates easily. I am at the end of my teather on this one.

The petrol gauge is also suspicious as it sometimes shows a high reading. I have a 90 amp BMW alternator and a 100 amp battery. Is it possibly a faulty alternator or voltage regulator, short circuit somewhere, wires rubbijng together. The windscreen wipers keep blowing which suggest some kind of fault somewehere. Driving at night in the desert with the water temp needle fully on red is not a pleasant one!

Any one out there experience the same problem. Anyone reading this in Africa or passing, I am at the Tergit camping by the beach, north on Nouakchott by the plage des pecheurs.

Cheers,


Andy

Hai Andy,

Electrical-meter's are very sensitive to small changes in electrical current. That is the way they operate. If you can touch the water-hose after 6 hours (or even 1 hour) and the thermostat is OK (feel the bypass-hose or compare a radiator-hose with a cold and warm engine), the engine-temp is fine.
I think you should look for either a bad contact in the wiring from the sensor to the meter (put in a new temporary wire to test it) or maybe the regulator is "not to well"
Also the meter itself can be broken, it's a delicate thing.
If you can't fix it, and don't want to drive with a faulty meter, buy a cheap inside/outside thermometer and tape the outside-sensor to either the thermostat-housing or the by-pass-hose. That way you know what the temp. is doing.

Good luck
Maarten

The problem of the temp gauge running in the red on the petrol 2.25L has happened several times to me. The problem was in all but two occasions not an overheating issue, but rather an electrical issue. Here's my history of temperature gauge running in the red on the 2.25 Petrol!
1) cause: thermostat not opening properly - temp gauge was ignored. Some 3000 km later a piston exploded (Zambia, 1988).
2) cause: short in the wire running to the temp sensor near the thermostat. The short automatically makes the resistance zero and the temp guage run immediately into the redh (back yard, UK, this year). Lifting the wire away from the hot tappet cover - which had melted the insulation, revealed the problem.
3) everything working fine in the coolant circuit, electrics fine but temp gauge running in red (thick sand, Tenere, Niger, 2000). The engine was running too hot. Fitting a bigger fan (from a 2.6L petrol) solved the problem immediately and the guage ran in the middle again.
4) cause: voltage regulator not working properly, no real overheating problem. Using the fuel guage (which also runs thru the voltage regulator) to diagnose this is not really reliable, because the variable resistor which lies in the fuel tank is itslef not very reliable.

Start the vehicle from cold and run the machine at idle. If the temp guage climbs immediately to the red, without any visible sign of excess heat in the motor (e.g. stinking hot radiator) probably points to an electrical problem. If the guage only runs into the red in sand, the chances are that the cooling system just isn't coping. That was my experience in December 2000 in Niger in a 2.25L. Fitting the 2.6L fan solved things, until I drove through Europe and the carb froze up. I've now fitted a back up electrical fan.

Same problem happened to me also. The moment we rolled off the ferry to France the gauge went up to near the red, and stayed there until we returned to Blighty.

Tried all the things you tried, but never found a fault. Never had any probs with engine blowing up either.

Worth noting that the first thing to go for us when driving in soft sand in temps of > 50 degrees Celcius (Wadi Rum, Jordan) was that the fuel vaporised in the line somewhere around the fuel pump and so no fuel got through. Tie a wet rag round the fuel pump, or just stop for a while...

Any more Qs let me know