Thread: Auto overheating/ slipping

Hi if its the engine temp gauge, I would see check if the cooling system first. Did they remove engine to do auto was system bleed properly. Check the simple things first. I have dropped and auto line before out bush (300 tdi) and it did not effect box or engine. I had to creep 50 klm with limited oil in tranny due to location I was at.

Hi Bazzle, the box was rebuilt completely, so i'm led to believe, also all the transmission cooling lines and cooler was replaced, bypassing the old one.

They did not remove the engine.

The symptoms are the same symptoms that appeared after the cooling line burst and then repaired;

-Higher fuel consumption
-Clutch slippage/ higher revs for not much acceleration
-Overheating and warning light.

is the temp gauge for the engine only? Or the transmission as well? What does the light indicate?

I have read that in almost all cases a burst cooling line will not incur permanent damage unless absolutely careless. I pulled over immediately when it broke and did no further driving. I'm hoping I haven't paid for a rebuild when one was not actually needed.

I will stand corrected. I believe the temperature gauge is of engine temp only and a transmission warning light for hi transmission temperature. Perhaps you have two separate issues. Check your cooling system first. Then get Transmission checked. I cant offer a suggestion as to why the engine is overheating.

Originally Posted by str405

.... the temp gauge steadily rose before dropping competely and being replaced by the temp warning light....... Overheats at start of a trip usually, rising then dropping off completely and temp light appearing accompanied by 'slipping' feeling at around 80- 110kph.

....

that's a symptom of failing engine coolant temperature sensor or problem on it's circuit, on overheating the gauge doesnt drop it stays at the top of the scale... that slipping feeling might be the result of the ECU's overheat protection strategy which reduces fuelling when it gets high temp input... maybe you are lucky to escape easily so better replace the ECT sensor first of all, here's the relevant part from RAVE:

The ECT sensor can fail the following ways or supply incorrect signal:
l Sensor open circuit.
l Short circuit to vehicle supply.
l Short circuit to earth.
l Incorrect mechanical fitting.
l Signal fixed above 40 °C (104 °F) not detected.
l Signal fixed below 40 °C (104 °F) not detected.

In the event of an ECT sensor signal failure any of the following symptoms may be observed:
l Difficult cold start.
l Difficult hot start.
l Driveability concerns.
l Instrument pack temperature warning illuminated.
l Temperature gauge reads excessively hot.
l Temperature gauge reads excessively cold.
In the event of component failure the ECM calculates coolant temperature from the fuel temperature sensor signal. If
this occurs, the limit engine operation if coolant temperature is too high becomes inoperative.

Ok thanks Sierrafery!

The car is in a transmission shop in Albury, will pass these suggestions on asap come Monday morning.

Other forums including other threads in Aulro are suggesting a sensor failure somewhere.

Much appreciated input guys, will keep this thread updated!

Thanks!

Originally Posted by sierrafery

that's a symptom of failing engine coolant temperature sensor or problem on it's circuit, on overheating the gauge doesnt drop it stays at the top of the scale... that slipping feeling might be the result of the ECU's overheat protection strategy which reduces fuelling when it gets high temp input... maybe you are lucky to escape easily so better replace the ECT sensor first of all, here's the relevant part from RAVE:

The ECT sensor can fail the following ways or supply incorrect signal:
l Sensor open circuit.
l Short circuit to vehicle supply.
l Short circuit to earth.
l Incorrect mechanical fitting.
l Signal fixed above 40 °C (104 °F) not detected.
l Signal fixed below 40 °C (104 °F) not detected.

In the event of an ECT sensor signal failure any of the following symptoms may be observed:
l Difficult cold start.
l Difficult hot start.


l Driveability concerns.
l Instrument pack temperature warning illuminated.
l Temperature gauge reads excessively hot.
l Temperature gauge reads excessively cold.
In the event of component failure the ECM calculates coolant temperature from the fuel temperature sensor signal. If
this occurs, the limit engine operation if coolant temperature is too high becomes inoperative.

Similar sensor and connectivity faults leading to drivability issues have been seen before following transmission fluid hose failure. Whether it is just contamination of connectors by the fluid or more complex electronic side effects from that is worth investigating.
Nick

Do you mean exactly that kind of ECT gauge behaviour? as the needle to drop down all the way? ... i dont contradict you but it's interesting and strange as the ECT sensor is hardwired to the ECU no lower connector which can be hurt by oil is involved though is suspect that for me too that this symptom occured immediately after the transmission oil loss ... i'm watching this with interest cos if it's so we can put it in the "LR oddities" section then

Originally Posted by sierrafery

Do you mean exactly that kind of ECT gauge behaviour? as the needle to drop down all the way? ... i dont contradict you but it's interesting and strange as the ECT sensor is hardwired to the ECU no lower connector which can be hurt by oil is involved though is suspect that for me too that this symptom occured immediately after the transmission oil loss ... i'm watching this with interest cos if it's so we can put it in the "LR oddities" section then

Not the same. You may remember one about 6 months ago which after a hose failure and repair ran well once and would not start the second time and threw up all sorts of error codes including CAN faults. I had a look and was puzzled and defeated due to lack of time (I never did find out the outcome). I wonder if there are ECU/BCU effects or damage from the fluid contamination as the one I mentioned was also running fine before the hose gave out.