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MG MGF Technical - How hot is an MGF?

Does anyone know how hot in oil temperature terms an MGF should ideally run at?
On the motorway mine constantly runs at 110C and the fan is always on.
Is it possible to sustain high speed 100mph in an F since at this speed it runs at over 120C.
On a hot day (!) it constantly runs hot 120C and the fan comes on.
The engine bay is like a little cooker, touching the rear pannels after a long run the paintwork is scorching.
Is not surprising these cars are prone to HGF when they constantly run over 10C hotter than what they would in a Rover 200.
Bryan

Bryan,

If the engine bay fan or radiator fans are coming on while driving on the motorway then I would say that was not normal. Those fans are meant for slow driving in traffic when there is no forward movement to circulate the air.

My VVC runs at 100-110 degrees on the oil temp gauge when driving at constant 70mph but rises higher with the cruising speed.

How do you know that the fan is coming on when on the motorway and which fan/s do you mean?

Bruce
Bruce Caldwell

I can tell the fan is on when on the motorway since the second I exit and listen I can hear it. By fan I mean the big cooling fan in the engine bay.
I agree there is plenty of cool air available for the engine when on the motorway, but wondered if this was a characteristic - constantly running hot.
Roll on second HGF.
Bryan

What does your temp gauge say? It should never go above half way.
Martin

It always reads under half way regardless of the other guage or fan coming on.
Bryan

I would suggest getting some measurements done of the temp within the engine bay. Measure the temp by the engine bay sensor which is at the top on the RH side.
Teh fan should switch on at 75c in an MPI and 85c in a VVC. It should switch off at 65c and 75c correspondingly. If the engine compartment temp rises to 130c then a warning light will show on the instrument panel.

The sensor may be wrong and bring on your fan at too low a temperature. The scorching panels are normal (to a certain extent) and it will be difficult to touch the panel above the engine for some time after a run, especially with the warmer weather.

The high running temperature of the oil is not usual, unless you are really caning the car. Together with the fan coming on warrants further investigation. The gauges are notoriously innaccurate. Perhaps check if the radiator fan is running when you are travelling at speed. If it is then something is very amiss. You could check your oil temp by asking an MOT garage to check the temp with their sensor down the dipstick tube and compare with the reading on the dash but remember the dash sensor is not in the sump. It would give some indication. The MOT garage runs your engine up to temperature by measuring the oil temp down the dipstick tube.

HTH

Bruce
Bruce Caldwell

I have just got back from my nearest MG-R dealer, after ordering a workshop manual. Whilst there, I asked the service manager what the oil temp. should be - his answer ?? "No idea - try asking on one of the MG-F owners' web sites" !!

Jonty
John Tait

No one has mentioned the variance between the calibration difference between pre and post 2000 model year cars. The difference is that the newer cars read a consistant 20 to 30 degrees higher than actual temp due to the changes in guage for the later cars. Temp inaccuracy has been confirmed by use of separate oil temp measurments.

Rog
Roger Parker

Sort of oil used has also influence IMO.

Had 0 W30 in until last weeks 40k km Service. Never got more then 120 °C at 100 mph average on the motorway in the last month.
They filled now 10 W40 (Castrol GXL) and I believe to seeing the oil temperature 5 to 10 degrees increased now.
I'll keep an eye on it.
Dieter Koennecke

Did 250 miles motorway driving on Thursday - one of our hotest days yet - at constant 80 - 90 mph. Oil temp stayed at about 105 degrees.

Has anybody ever tried adding a warning LED to indicate fan/s cutting in?

Tony

PS: Wonderful drive, but some still had the roof up ! Strange ! :-(
Tony


Hi Tony,
I have some things for that on my desk at the moment - but too nice wether to stay in the garage for the fitment :) As there is no idea to simply put a LED as "telltale" of voltage to the fan(s) due to the fact that the fan can still be badly connected it has to be done another way ! Many cars has a type of "DC current transformers" that actually senses that there is current drawn to the source without significally induce any voltage drop across the device. With such an unit in series with the fans it would be possible to be 100% sure that the fans are actually working when the LED is on. So a few vintage Volvo "broken lamp indicators" will do the trick. Unfortunatly the latest system with CAN -busses will be a bit too complicated to fit... But as said - a typical winter job.
Regards , Carl.
Carl

Hi

Probably not a great deal of help but my 99 vvc never goes about 95 the only time i got it to go 110 was 130mph down a track for a mile or so

Paul
paul

Carl,

Sounds like a good way to do it. I'll look forward to hearing more as the dark nights close in! :-))

Tony
Tony

Tony,

My VVC has a warning LED fitted for the water temp rising above a preset level. Also another LED to warn of fuel going lower than preset level. Both LED circuits also operate a short beep as an audible warning. Water temp LED is most usefull. It shows that the water temp rises fractionally about a minute after I come off the motorway and settles back down about a couple of minutes after that. The amount of temp rise is hardly noticeable on the gauge.

I decided that by the time the fans cut in it might be too late for a warning, especially if I was still travelling fast at the time. So wired up a circuit to the water temp sensor.

Bruce
Bruce Caldwell

Hi Guys,

I just got back from the South of France and on the way back I was rushing to make the ferry so was cruising at 115-120 MPH for ages... The fuel consumption at that speed is not very good at about 250miles/tank! The outside temperature was about 25C.

I had an oil change(10 W40) done in Cannes before I left. The gauge hovered around 110-125 which was quite hot in my experience.... Great fun though particularly when I dropped the windows and wind deflector then directed the rushing air over the windscreen to my head for a free massage! :)

Well I'm off to Le Mans soon!

Cheers RichieR
RichieR

Bruce,

Any chance of a circuit diagram of what you've done?

Tony
Tony

Hi,

<Had 0 W30 in until last weeks 40k km Service>

Interesting, Dieter. Do you know what the 0W-30 oil was? Possibly synthetic?

Another interesting feature (to me) is that the oil temperature can be 90 or 100 when you switch the engine off, but if you sit in the car with the ignition on the oil temp drops quite quickly. Start the engine again and it takes a little while to creep up again. It seems as if the oil is able to dissipate its heat quite well.

Regards, Kes.
Kes

Kes,
synthetic, of course. Can't recall the marque.

Bruce,
I'd like to see the circuit as well.
Not to me currently. I'm off for 8 days vacancies.

Dieter
Dieter Koennecke

This thread was discussed between 11/05/2002 and 24/05/2002

MG MGF Technical index

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