Oil Temp. Warning Light
Moderator: Committee Members
Forum rules
Not many rules really, this board being aimed at technical issues, it shouldn't fall foul (hopefully) of some of the more personal issues that can affect forums.
Rule 1 - Is that you need to think very carefully before posting anything technical or asking anything technical relating to the security system of the car - See 'Security Issues' sticky for more info.
Rule 2 - We (MGF Register) do not support copyright infringement and therefore references to CD ROM, PDF versions or paper copies of the workshop manual (for instance) should not be posted on the forum. We don't want to get into trouble and we'd rather sell you a genuine hard copy through our Regalia shop anyway!
Because advice is honestly and freely given in this technical section, much of it will be amateur experienced based, so any information is given in good faith and is not guaranteed as correct.
Not many rules really, this board being aimed at technical issues, it shouldn't fall foul (hopefully) of some of the more personal issues that can affect forums.
Rule 1 - Is that you need to think very carefully before posting anything technical or asking anything technical relating to the security system of the car - See 'Security Issues' sticky for more info.
Rule 2 - We (MGF Register) do not support copyright infringement and therefore references to CD ROM, PDF versions or paper copies of the workshop manual (for instance) should not be posted on the forum. We don't want to get into trouble and we'd rather sell you a genuine hard copy through our Regalia shop anyway!
Because advice is honestly and freely given in this technical section, much of it will be amateur experienced based, so any information is given in good faith and is not guaranteed as correct.
-
Bikibob
- Posts: 7
- Joined: Wed Mar 15, 2017 8:18 pm
- MGF Register Region: Midlands
- Model of Car: 2004 TF160
- Location: Malvern
- Contact:
Oil Temp. Warning Light
2004 TF160 the red warning light for oil temperature is flashing all the time from starting up and continuous driving. The temperature on the gauge is ok at about 100 deg. Does anyone know the cause of the flashing warning light please.
-
Chris Tideswell
- Posts: 829
- Joined: Mon Oct 08, 2007 5:58 pm
- MGF Register Region: Midlands
- Model of Car: TF 135
- Location: Shepshed Leicestershire
- Contact:
Re: Oil Temp. Warning Light
Does the temperature gauge go straight up to 100 deg or does it creep up gradually as normal?
I think that this circuit diagram will be from an F and could be quite different to the 04 TF, however the both the warning light and grudge are fed directly from the same sensor so if the gauge is working it suggests a bad connection or a damaged wire.
https://www.mgfcar.de/schedules/sb34.jpg
I think that this circuit diagram will be from an F and could be quite different to the 04 TF, however the both the warning light and grudge are fed directly from the same sensor so if the gauge is working it suggests a bad connection or a damaged wire.
https://www.mgfcar.de/schedules/sb34.jpg
-
Rob Bell
- Committee Member
- Posts: 14425
- Joined: Tue Oct 02, 2007 2:36 pm
- MGF Register Region: South East
- Model of Car: MGF 1.8i + MGF Shed!
Re: Oil Temp. Warning Light
Thanks Chris - I always thought that the VVC oil temperature warning lamp on the VVC was operated via the ECU rather than the signal for the oil temperature gauge - as this was only ever a feature of the VVC on the pre-MEMS3 cars. Every day is a learning day! 
Question then arises as to how the signal is then interpreted as a signal to illuminate the warning light. Here, the wiring diagrams I have here are unhelpful as there must be a potentiometer built into the instrument pack to illuminate the lamp once the voltage signal reaches a certain threshold.
My hunch here is that this is something relatively simple (although I confess to only having access to electrical diagrams up to 2003). Most likely is a poor connection to the instrument pack - probably a loose or dirty connector. If that is not the case, then either there is a damaged wire (check the voltage or resistance of the signal wire to the instrument pack) or the fault is within the instrument pack - which would be a very unusual fault given that these components are generally extremely reliable!
Question then arises as to how the signal is then interpreted as a signal to illuminate the warning light. Here, the wiring diagrams I have here are unhelpful as there must be a potentiometer built into the instrument pack to illuminate the lamp once the voltage signal reaches a certain threshold.
My hunch here is that this is something relatively simple (although I confess to only having access to electrical diagrams up to 2003). Most likely is a poor connection to the instrument pack - probably a loose or dirty connector. If that is not the case, then either there is a damaged wire (check the voltage or resistance of the signal wire to the instrument pack) or the fault is within the instrument pack - which would be a very unusual fault given that these components are generally extremely reliable!
-
Bikibob
- Posts: 7
- Joined: Wed Mar 15, 2017 8:18 pm
- MGF Register Region: Midlands
- Model of Car: 2004 TF160
- Location: Malvern
- Contact:
Re: Oil Temp. Warning Light
Thanks for this guys. I cannot understand why the TF160 needs a warning light in addition to the oil temp gauge. However your info is helpful and suggests that it is simply a gremlin in the wiring and nothing serious to worry about.
-
Rob Bell
- Committee Member
- Posts: 14425
- Joined: Tue Oct 02, 2007 2:36 pm
- MGF Register Region: South East
- Model of Car: MGF 1.8i + MGF Shed!
Re: Oil Temp. Warning Light
Yes, assuming that the gauge is not at fault of course! But the TF160 has an oil cooler, so you'd hope that the oil temperatures weren't becoming excessive...
-
Chris Tideswell
- Posts: 829
- Joined: Mon Oct 08, 2007 5:58 pm
- MGF Register Region: Midlands
- Model of Car: TF 135
- Location: Shepshed Leicestershire
- Contact:
Re: Oil Temp. Warning Light
I suspect it is fitted to VVC F/TF’s due to the engine bay fan kicking in 10deg higher then on Mpi cars. As to why the engine bay is allowed to run hotter is another question…
Re: Oil Temp. Warning Light
The oil temperature warning lamp (LED) is connected to to both the Oil Temperature Gauge and the Oil Temperature Sender. The sender is the one next to the oil filter. It seems to need the resistance of the OEM Oil Temperature Gauge to work. If you disconnect the NU (Brown/Blue) wire from the oil gauge, or put a non OEM oil temp gauge in its place the Oil Temp Warning Lamp will come on much earlier. Found out when I fitted a digital Oil Temp Gauge with the OEM oil temp sensor
-
Rob Bell
- Committee Member
- Posts: 14425
- Joined: Tue Oct 02, 2007 2:36 pm
- MGF Register Region: South East
- Model of Car: MGF 1.8i + MGF Shed!
Re: Oil Temp. Warning Light
That makes sense Mark - there will be a reference resistor in the instrument pack and once a threshold is reached, it'll illuminate the oil temperature warning light. A faulty gauge could also, therefore, affect when the oil temperature lamp comes on - so important to check the oil temperature independently of the dial reading...