Auto overheating/ slipping

[str405]

Hello all,

Firstly, thanks in advance to everyone who gives input or advice.

I own a discovery 2 which recently on a long trip had a transmission cooling line burst and empty the contents of my transmission onto the highway!

I did not notice anything until I realised my revs were steadily increasing, but with no expected acceleration. I pulled over to find the underside of my discovery oily, and only later discovered the broken hose (after being towed to a nearby country town.)

I had a truck mechanic repair the hose and refill my transmission. Shortly after this fix, And back on the road (maybe 2km on) the temp gauge steadily rose before dropping competely and being replaced by the temp warning light.

Pulled over to let cool, seemed fine but around the 80 - 110kph region it felt as though a clutch was slipping. It also consumed approx half a tank for a 250km highway trip. Seems high to me.

Eventually had an auto transmissions place recommend a rebuild citing that the cooling system likely had a blockage and that the transmission needed a new torque converter/ clutch plates. Had work done for approx $5k.

Picked up the car yesterday, same issues!
Overheats at start of a trip usually, rising then dropping off completely and temp light appearing accompanied by 'slipping' feeling at around 80- 110kph.

Have left with auto trans shop as still under warranty. But out of a car again...

Any ideas anyone?

Love the car, but have only owned for two months and already almost $6k in towing and repairs and am beginning to be a little dismayed.

2002 discovery 2 auto, 170 000km.

[Bazzle218]

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.

[str405]

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.

[Bazzle218]

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.

[sierrafery]

.... 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.

[str405]

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!

[Pippin]

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

[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 :confused: ... i'm watching this with interest cos if it's so we can put it in the "LR oddities" section then

[Pippin]

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 :confused: ... 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.

[str405]

Brilliant, thanks very much guys, will recommend to the shop to change the coolant temp sensor and check other temperature sensors.

Will report back.

:)

[scarry]

Couple of things,was the temp warning light for the transmission or the engine?

The Auto needs to be filled to the level plug,then the vehicle run while in neutral and more fluid added until it runs out the level plug.
I wonder if the repairer did this?

Low fluid level may cause the slipping.

[str405]

Couple of things,was the temp warning light for the transmission or the engine?

The Auto needs to be filled to the level plug,then the vehicle run while in neutral and more fluid added until it runs out the level plug.
I wonder if the repairer did this?

Low fluid level may cause the slipping.

This is what I don't understand - is the light for the engine or the transmission or both? And what about the gauge, both too?

The transmission was definitely full to the top both after repair and after rebuild. After repair it was checked by two mechanics, both said it was full.

[sierrafery]

This is what I don't understand - is the light for the engine or the transmission or both? And what about the gauge, both too?


The temp gauge and warning is exclusively for the engine

[thai_tiger]

warning light for trans looks like this

https://www.aulro.com/afvb/images/imported/2017/06/187.jpg (http://www.google.com.au/url'sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjT2qb1x8bUAhXRq5QKHVq0C9cQjRwIBw&url=http%3A%2F%2Fwww.landroversonly.com%2Fforums%2 Ff40%2Fwarning-light-127826%2F&psig=AFQjCNE0yD5Ls171GEcylQNroAkRl1gIRw&ust=1497846695671046)

[str405]

warning light for trans looks like this

https://www.aulro.com/afvb/images/imported/2017/06/187.jpg (http://www.google.com.au/url'sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjT2qb1x8bUAhXRq5QKHVq0C9cQjRwIBw&url=http%3A%2F%2Fwww.landroversonly.com%2Fforums%2 Ff40%2Fwarning-light-127826%2F&psig=AFQjCNE0yD5Ls171GEcylQNroAkRl1gIRw&ust=1497846695671046)

Brilliant, thanks thai tiger, all makes sense now!

[str405]

Quick update, have a coolant temp sensor on the way and will fit when it arrives, as well as a new thermostat. I rechecked my coolant level two days ago after noticing waterfall sounds behind dash and it was low, needed about 1litre of fluid maybe. Seems to have stopped that overheating issue for now but does this now mean a bad head gasket? Surely not at 170 000km. Or am I overestimating the d2? No obvious coolant leaks, ground is dry when car is parked when both hot and cold.

[Pedro_The_Swift]

wow,, 16 posts and i cant tell if its a V8 or not,,
170K and needing fluid?
sounds like a V8,,

[Pedro_The_Swift]

Oh and Thai-Tiger?

thanks for the MPH dash,,

[biggrin]

[str405]

It's a td5

[Pedro_The_Swift]

If its not leaking on the ground theres only one other way out for coolant,,


and there are plenty of GREAT TD5 head gasket tutorials here,,
so dont feel its a one off thing,,, [wink11]

also dont jump to that conclusion, get the rad gasses tested...

[str405]

Update! The d2 appears to be driving without any problems now and won't register that it's overheating.

I'm guessing that there was air in the coolant system and that sometimes this would pass over the temp sensor and cause it to return funny readings.

I'll still change the thermostat and temp sensor when I next get a chance to.

I'll repost to this thread if the symptoms return.

Many thanks to everyone for all their input! This is a fantastic webforum :)

[Pippin]

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.

Hi Sierrafery,

For your info.

Evidently the ECU had failed on this one and ran fine when replaced. Maybe it's worth taking care when pressure cleaning ATF from a burst hose by disconnecting the battery and cleaning all the connectors with switch cleaner and letting it all dry out before restart.

Nick

[str405]

Update - over the past month or so the discovery has been behaving well apart from a slow loss of coolant. Have had to use approx 5 litres plus over the course of 4 weeks or so or about 1500km. It seems to be worse after a long highway drive.

Today spotted first sign of an external leak, best I could tell was that the highest wet spot was the bottom right corner of the radiator as you look at it from the front of the vehicle. Will get a better look tomorrow but I assume the leak is getting worse if showing obvious external signs now.

[Pedro_The_Swift]

This from RAVE,,
shouldnt be any hoses around there,,
[bigsad]
126609

[str405]

Looks like there has been an attempted on-the-run repair job of the lower right corner of the radiator as it is covered in silicon. The highest wet patch is here on the rear side, pooling on the chassis.

Are these radiators known to crack?

I'm guessing a new radiator is on the cards. I have photos of the spot that I'd like to post but can't work out how to upload them!

[Pedro_The_Swift]

one way is--

reply to thread,
manage attachments,
add files,
browse and upload,
insert line
done.

quick hey![bighmmm]

[str405]

Got it! I was on the mobile site and not the full site...

photo appears upside-down, can't seem to flip it :/

photo shows the rear of the radiator, bottom left hand corner where the silicon seems to have been smeared. Photo was taken from the left wheel arch after removing access hatch.

[discorevy]

Looks like the right hand side , I'd be pulling the radiator as that looks like a botch job.

[Pedro_The_Swift]

The good news is that it looks like someones played with the auto cooler connections[smilebigeye]

The bad news is someone has played with the bottom of the radiator:eek2:[bigsad]

quite a few threads on replacement rads,,

[crash]

Also looks like green coolant - you need to be using the red OAT coolant if a TD5.
I would be replacing the rad.