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MG MGF Technical - Oil temp gauge running higher than usual - worried


I'm worried...

My oil temp gauge is now running high than normal - even on short journeys. I'm not thrashing it and have the heating on full to try and get heat away from the engine. It's a MY2000 and usually runs around the 120 mark but for some reason it has gone over half way and heading to the red !!!

I can only presume that the cooling system isn't working properly. How can I verify the cooling system is working - are there any checks I can do. ???

I'm due for the coolant changing anyway, (which I was going to do myself), but I guess a garage may need to take a look first ???

Any thoughts before the dreaded HGF happens.

P.S. Any good garages in Cheshire


There was a well known and common fault with the Oil Temperature Gauges on the MY2000 F where they were giving false high readings - there is a lot in the archives on this BUT you must be a member (free to join) and signed in.
Ted Newman

IIRC the Oil Temp problem was due to a wrong resistor fitted causing an incorrect calibration. Dieter's site will have the detail. This will not cause a 'change' in reading.
You do not say that you also have an increase in coolant temperature so you can discount this as causing the oil temp to rise. In fact there is little relationship between coolant and oil temp as I get 150 Oil and normal coolant when pushing hard thru Alpine Autobahns in the summer high 30s.
Geoff F.
G. Farthing

Typically, the oil temp calibration issue is found on cars from new, and doesn't seem to develop over time (I stand to be corrected!)

Therefore, I don't think that this is the problem here. A faulty sender tends to provide low readings rather than high.

Not sure what the problem is here Darren, but I would recommend an oil change- frequently people report cooler running with new oil.
Rob Bell

The coolant temp is fine - just the oil temp, more worryingly on short journeys.

I'm one of these sado's who watches the temp gauges more than the road !!! Can't work out why the sudden rise in oil temp though, (especially now the ambient temp is cooler).

Is there an easy way to check coolant is running through the system. Checked after the journey and no fluid was running out of the upper pipe in to the expansion tank. I'm no expert but I thought there would be a constant stream into the expansion tank when it's hot.


Decided to bite the bullet and get the coolant changed along with aluminium pipes from Mike Satur.

Maybe get a new rad as well if the existing one is no good. Anything else I can do the keep the cooling system at optimum performance ???

A B&G coolant level sensor is IMO a very good investment :o)
Rob Bell

How long generally do the standard coolant pipes last before corroding.

Mine are over five years and have been told that they are on their way.

Depends. The root cause of the problem, so I am told, is paint damage to the pipe's brackets when the car was assembled. Some cars therefore last a very long time. Others go very quickly.

I'd say that the median life span is around 5 to 7 years.
Rob Bell

<<no fluid was running out of the upper pipe in to the expansion tank. I'm no expert but I thought there would be a constant stream into the expansion tank when it's hot.>>

Coolant only runs out of the small pipe when the thermostat is closed. Once the engine is hot the flow stops from the small pipe at the top.

My wife's nephew has an MGF 2000Y and a few weeks ago he rang me from the roadside to ask why his engine oil temp was rising even though he was cruising in traffic at 50 mph. As I spoke to him his water temp went up rapidly and it turned out to be a cracked water pump casing. Subsequently repaired to be followed a week later with an HGF. The repairers were experienced chaps so I would assume they knew how to bleed the system correctly. Why the rise in oil temp? I dunno!!

Doesn't help much but I sympathise. My car is running cold at the moment because (I think) the thermostat is jammed open!

Bruce Caldwell

Either that Bruce, or your temperature sensor is sitting in a pocket of air - I think that this happened to me prior to the engine outlet hose failing completely, and taking with it the head gasket :o(
Rob Bell

Which ever way Rob, it still stopped me from going to Gaydon last Sunday> The water level hasn't dropped at all. It reaches normal and then drops to 3 marks below 'normal'. Hopefully Techspeed will sort it out by changing the stat on Friday.

Bruce Caldwell

This thread was discussed between 17/10/2005 and 19/10/2005

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