Strange auto gear upshift & running temp query

[mediaseller]

Hi Folks.

Having just come back from Cornwall in my 1994 2.7td Mistral I noticed that when the engine gets up to a certain temperature the auto gearbox will shift up in to a higher gear causing the engine to rev high. Since owning it I have noticed that the temperature gauge never moves much above it's base position unless hammered hard for a considerable distance.

I always thought that engines should ideally run about midpoint on the gauge but I'm not sure with this vehicle, so I suspect either the temperature sensor is faulty or someone put the wrong one in. What should the temperature be?

Coolant water is being used at an alarming rate but can't find a leak and no steam coming from the exhaust. Additionally no coffee coloured coolant. (Suggesting a head gasket failure).

My theory is that when the engine reaches a certain temperature the exhaust gas gets too hot while moving through the turbo thus reducing the air density and making the auto gearbox to change gear in order to maintain road speed.

Another question is would it be possible to retrofit an intercooler to this model to improve performance?

My car has the original viscous radiator fan and would changing to an electric fan improve matters?

Your comments would be most appreciated.

:bow

 

[solarman216]

Hi Folks.

Having just come back from Cornwall in my 1994 2.7td Mistral I noticed that when the engine gets up to a certain temperature the auto gearbox will shift up in to a higher gear causing the engine to rev high. Since owning it I have noticed that the temperature gauge never moves much above it's base position unless hammered hard for a considerable distance.

I always thought that engines should ideally run about midpoint on the gauge but I'm not sure with this vehicle, so I suspect either the temperature sensor is faulty or someone put the wrong one in. What should the temperature be?

Your comments would be most appreciated.

:bow

A little confused, "shift UP" causing the engine to rev high" can you explain?

temp on these is normal about 7 to 8 oclock, 9+ and it is getting hot, Rick

 

[briggie]

i suspect that you either ..

have the wrong thermostat in

no thermostat in

and are possibly low on atf

also perhaps your mode selector switch is going into " power mode " when you press the loud pedal too hard , or the engine is under too much load for the conditions .

 

[solarman216]

Hi Folks.


Coolant water is being used at an alarming rate but can't find a leak and no steam coming from the exhaust. Additionally no coffee coloured coolant. (Suggesting a head gasket failure).

My theory is that when the engine reaches a certain temperature the exhaust gas gets too hot while moving through the turbo thus reducing the air density and making the auto gearbox to change gear in order to maintain road speed.


Your comments would be most appreciated.

:bow

Sounds like head gasket to me, to check this, remove the rad cap (engine warm) remove the header tank cap (make sure it is about half full) place plastic bag then rag over rad filler and place your hand on it to provide a good seal (the plastic bag and rag are to protect your hand, if like me you have hard skin then just use your hand) now repeatedly rev the engine to try and induce a load, and watch the header tank water, if you see bubbles after the initial due to a little air in the rad cap hole then head gasket for sure, if no bubbles either the HG is OK or you are not loading it enough, s get a trusted mate to put it in gear and load it this way while giving it a few revs, but not for long you do not want to overheat the box, Rick