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cedwat
Member Since: 16 Nov 2007
Location: North
Posts: 179
  
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| Help ! Engine heats up on motorway! |
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Hi,
I am in the middle of a 1400 km trip. In the first part, I had 5-6 times the sa e symptom:
- cruise control stops
- water temperature begins to climb
- no aircon
- then, I lower my speed, even go neutral and "d" again
- there is a noise like a second engine starting (like when you start the d3 in the morning)
- temp goes back to normal (middle mark)
- aircon commes back
- later, cruise control works again
Any ideas?
700 km to do the day after tomorrow.
THanks ! My fifth Disco ...
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 2nd Jun 2011 7:01 pm |
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Bodsy
Site Sponsor
Member Since: 06 Nov 2006
Location: In the Clubhouse
Posts: 21361
  
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2nd engine is the sound of the Viscous fan cutting in to try to cool things down. Have you checked the water level? (after the car has cooled down of course) Bodsys Brake Bible
D4/D3 Remote FBH heat kits
BAS Remaps/ EGR Blank
Transmission Flush
Software updates/enabling
Clock/ SNOTM /3Flash / 4x4Info /BT Update /Service Reset/Error Codes / Gearbox Reset
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| 2nd Jun 2011 7:44 pm |
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cedwat
Member Since: 16 Nov 2007
Location: North
Posts: 179
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I have stoped to buy liquid but didn't check the level as it was too hot to do it. Will check tomorrow morning.
My feeling is my viscous fan is tired and does not go in action when it should? Going in N and then in D seems to awaken it? Possible ?
Recently I had been surprised several time to hear that viscous fan going on action on the motorway. I thing that I did not hear that in the past. Do you have this happening sometimes on the motorway? Or is it unusual? My fifth Disco ...
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| 2nd Jun 2011 7:55 pm |
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Bodsy
Site Sponsor
Member Since: 06 Nov 2006
Location: In the Clubhouse
Posts: 21361
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your intercooler could be blocked with mud also? that would get the fan working harder. But as the temp goes up, suspect there's a dodgy temp stat somewhere.  Bodsys Brake Bible
D4/D3 Remote FBH heat kits
BAS Remaps/ EGR Blank
Transmission Flush
Software updates/enabling
Clock/ SNOTM /3Flash / 4x4Info /BT Update /Service Reset/Error Codes / Gearbox Reset
See It Here
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| 2nd Jun 2011 8:07 pm |
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cedwat
Member Since: 16 Nov 2007
Location: North
Posts: 179
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Oh mud yes ... Maybe. Oops. Thanks for the clue. Maybe some washing to do.
Translation problem: I don't understand your last sentence? My fifth Disco ...
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| 2nd Jun 2011 8:27 pm |
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Bodsy
Site Sponsor
Member Since: 06 Nov 2006
Location: In the Clubhouse
Posts: 21361
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A temperature sensor possibly not working (Dodgy  )
You'll need to back flush the intercooler for a couple of hours in order to push the mud/dirt from the back to the front. Bodsys Brake Bible
D4/D3 Remote FBH heat kits
BAS Remaps/ EGR Blank
Transmission Flush
Software updates/enabling
Clock/ SNOTM /3Flash / 4x4Info /BT Update /Service Reset/Error Codes / Gearbox Reset
See It Here
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| 2nd Jun 2011 8:34 pm |
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Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
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A number of us have had this!!!
The good news is that the temp sensor is really easy to replace as it is at the top of the engine right near the front. Buy a new sensor, disconnect old one, replace with new one. No need to drain coolant or anything.
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| 2nd Jun 2011 8:40 pm |
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cedwat
Member Since: 16 Nov 2007
Location: North
Posts: 179
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Wouldnt a faulty sensor also make the temp gauge on the dashboard indicate wrong? Or is it a different sensor ? My fifth Disco ...
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| 2nd Jun 2011 8:49 pm |
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Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
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It's the same sensor, but rather than a true reading it is weighted to the normal position. The fan takes its cue from the same source, hence the roar of the fan when it thinks it is needed. When the sensor goes its quite subtle at first but as time goes on it gets worse and worse, with the temp sensor going full scale hot, with red flashing light for the complete effect before suddenly going back to the normal position. When the car thinks it is overheating it cuts out the cruise control and turns off the air conditioning. The roar of the fan gets attention too!
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| 2nd Jun 2011 8:56 pm |
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anglefire
Member Since: 09 Mar 2010
Location: In the Club House
Posts: 4180
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If the engine temperature is climbing and the fan cutting in, then it is more likely to be the actual radiator blocked with mud - which is a lot easier to clean that the Intercooler - due to it being only 25-30mm think and not nearer 100mm - not forgetting that there are actually two radiators, one in front of the other.
Take off the air intake pipe above the fan, (From the air box on the left as you look into the engine bay) to the right hand side where the intercooler pipework is located. Then take off the cover over the fan itself. You can then backflush the radiator - and the intercooler at the bottom too.
The radiator should only take 1/2hour or so to do, if its not too bad. Problem is the mud sets like concrete, especially in the IC and takes ages to soften enough to come out.
I use a hose onto a 450mm long length of 15mm copper pipe, terminated into a 90deg bend and then into a 15/8mm reducer.
Don't use a jet wash though. It will bend the fins  Mark.
2006, D3 SE Auto - gone but not forgotten.
2014 BMW 530d M Sport Tourer.
1977 Triumph Spitfire 1500
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| 2nd Jun 2011 9:09 pm |
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cedwat
Member Since: 16 Nov 2007
Location: North
Posts: 179
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I'll do that. I don't know if it is really heating up or if it is a faulty sensor. But cleaning can't do no harm ...
When I thnk about it, it is true that the temp gauge was suddenly climbing very fast up to 3/4 of the max and then back to normal very fast too. So it should indicate a faulty sensor.
But at the same time, my aircon shut down when it happened. Which would be indicate mud.
So I'll do both!
Anyways, this forum is really incredible. I got my answers in a blinck.
Thanks you very much for your help, gents! My fifth Disco ...
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| 2nd Jun 2011 9:21 pm |
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caverD3
Member Since: 03 Jul 2006
Location: Oberon, NSW
Posts: 6922
 
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I thought the viscous fan worked on it's own using the physical temp in the engine bay? So it would actually need to be hot. “There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely gamesâ€
Ernest Hemmingway
D4 3.0 Active Diff, Adaptive Lights, High Beam Assist, Surround Cameras, Privacy Glass.
D3 2.7:Adaptive Headlights,Electronic Rear Diff,ARB Bar,Blaupunkt Speakers,JVC Powered Subwoofer,Removable Snorkel,Mitch Hitch,Pioneer After Market Head Unit,Steering Wheel Control Adaptor,Remote Adjustable Supension Rod System, Taxside Dual Battery System.
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| 2nd Jun 2011 11:03 pm |
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Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
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No the fan comes off the same sensor, hence the rapidly varying temperature and (when indicating hot) the sound of the fan on max chat!
As discussed earlier the aircon cuts out on high temp as a safety measure. I still think these are all the signs of a bad sensor - a diesel engine is not capable of heating up and cooling down so quickly!
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| 3rd Jun 2011 7:36 am |
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caverD3
Member Since: 03 Jul 2006
Location: Oberon, NSW
Posts: 6922
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So not like the old ones.
I think the TD5 had both electric and viscous fans?
Like this?
http://www.industrysearch.com.au/Products/...rive-51050
Pretty clever. “There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely gamesâ€
Ernest Hemmingway
D4 3.0 Active Diff, Adaptive Lights, High Beam Assist, Surround Cameras, Privacy Glass.
D3 2.7:Adaptive Headlights,Electronic Rear Diff,ARB Bar,Blaupunkt Speakers,JVC Powered Subwoofer,Removable Snorkel,Mitch Hitch,Pioneer After Market Head Unit,Steering Wheel Control Adaptor,Remote Adjustable Supension Rod System, Taxside Dual Battery System.
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| 3rd Jun 2011 8:12 am |
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Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
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For more background on the D3 cooling system:
Quote:Coolant flows through the radiator from the top right hand tank to the bottom left hand tank and is cooled by air passing through the matrix. The temperature of the cooling system is monitored by the ECM via the Engine Coolant temperature (ECT) sensor located in the cylinder head. The ECM uses signals from this sensor to control the cooling fan operation and adjust fuelling according to engine temperature. For additional information, refer to Electronic Engine Controls (303-14C Electronic Engine Controls - 2.7L Diesel)
To control the cooling fan, the ECM sends a Pulse Width Modulated (PWM) signal to the cooling fan module (integral to the ECM). The frequency of the PWM signal is used by the cooling fan module to determine the output voltage supplied to the fan motor.
The ECM varies the duty cycle of the PWM signal between 0 and 100% to vary the fan speed. If the PWM signal is outside the 0 to 100% range, the cooling fan module interprets the signal as an open or short circuit and runs the fans at maximum speed to ensure the engine and gearbox do not overheat.
The ECM operates the fan in response to inputs from the ECT sensor, the transmission oil temperature sensor, the charge air temperature sensor, the A/C switch and the A/C pressure sensor.
ECT fitting instructions:
http://www.disco3.co.uk/gallery/albums/use...Sensor.pdf
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| 3rd Jun 2011 8:16 am |
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