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MG MGF Technical - Is my oil temp too much high?

I just got a used VVC, from july 1996 with 38k kilmeters (24k miles). Last wednday, i went on a highway after changing my engine and gearbox oil. After 10-15 of pedal to the metal, and the speedo marking between 220-225 km (135-140 miles). The oil temp started to raise until it reached 140 degrees. The air temp. was about 10-12 degreens. I just wonder if it was summer here ... the temperature usually raises to 35-40 degrees.I´m using MOBIL1 5W50 + SLICK50 Engine Treatment, and in the gearbox the Recommended oil + SLICK50 Gearbox & Differencial Treatment. Can anyone tell me if this is normal... or if the oil is really overheating, leaving me no other sollution then buying a Oil radiator. I also wondered if that time i kept that rythm for a more long distance, the temp would raised even more.
Bruno Valadas

That is a bit too hot, but perhaps not surprising if you're running it so hard. Whereabouts in the block is the oil temperature measured?

Having spent good money on the best oil you can buy you do not want to be putting Slick 50 in it.

Mike
Mike Bees

Sustained high speed does cause the oil temperature to go above 130 - I get it with my 1.8i (MPi) but I must confess that the occasion to do such speeds does not arise very often.

Ted
Ted Newman

I agree with Mike and Ted. What further action is determined by how often you travel at sustained high speed and how often the oil gets this hot.

If the answer is 'probably going to be very frequently' then it is worth considering the fitment of a thermostically controlled oil cooler.

It has to be thermally controlled to avoid OVER cooling of the oil under more gentle use- which is as bad as over heating under these circumstances.

I notice that the Demon Tweeks catalogue has a number of 'coolers available, but didn't notice whether they had thermostats?

Dieter, didn't you do a bit more research on this?

Rob
Robert Bell

Hi,
according to the oil cooler subject.
Sorry, '2' much projects for only one person ;-)
We agreed together on surely better and more constant oil temperture if an thermostat conrolled extended oil cooler is used, but thats all. The thread got to the archive with useful comments of Roger, including some data on 'standard' regulation temperatures, the thread data etc.

No more useful and complete data recently availiable from my side.
What I do recently is:
Take of the foot of the accelerator if the oil temp reaches 125 °C :-(
This may be a little over sensible, but I want to keep my engine healthy until a useful and economic solution is found on that.

According to engine oil additives: I've learned from lots of commends that I would never add anything to a top brand oil like Mobile 1. The 5W50 is IMO the best one for use in warm countrys, but WITHOUT ANY ADDITIVE.

According to gearbox oil additive: No idea, no experiance. Does it help against leaky drive shaft sealings too ?

:o)
Dieter

Dieter

A few of the MGF racers have oil coolers, but it sounds as though there are no "road cars" with this feature.

Seems that you'll have to be a pioneer if you take this route Bruno.

Can't remember what the recommended opening temp for the thermostat was... 110C?

Rob
Robert Bell

Hi Rob,
sorry, but sometimes I think that the archives does not content all data :-/ Or am I silly ? :/
I remember racimex and oil and cooler and added and some more possible keywords, but nothing appears ?
Anyway, a project for next year.
Dieter

Just to emphasise that the mix of additives and oil often does more damage than good. 'Additive packages' in quality oils are balanced for the complete range of operating conditions. Add an additional pot of compound and you can end up with additives from each acting in conflict or having an overdose of the same additive. Best described as potentially 'poisioning' the lubrication system.

I would be very interested to see what sort of oil temps you have when you use a quality engine oil on it's own!

Rog
Roger Parker

Strange but I was about to start a new thread to enquire about the oil temp on my 96 VVC. I've had it a couple of weeks and have been surprised that the oil temp has stayed so low. On my old Golf GTi, it would run around 98deg, but the MG seems so show temp around 70. Was wondering what people normally see for temp or could I have a faulty guage. Certainly never seen it rise above 80 yet. Advice please.
Gordon


Hi,

My oil temp hardly ever gets above 90 deg, but as Ted says it just isn't worth the risk to our licences to drive at sustained high speed here in the UK.

Synthetic oils have about 10% better heat transfer than petroleum oils, as well as creating less friction in the first place, so the oil temperature should be slightly less with Mobil 1. As for Slick 50, I used to use it (in my 214). One day in an idle moment I turned up a few articles on this stuff on the web, and went straight out and bought a new filter and a gallon of synthetic and flushed the stuff out. There are reports that it can clog filters, but how this, or any clash with the existing oil additives, will cause the oil to overheat I don't know. My guess is that changing the oil and filter would be a good thing, but it won't affect the oil temperature by any significant amount, which is not much help.

An intestesting point is that there is an additional oil temperature sensor on the VVC on the hydraulic control unit on the cylinder head, which is used to derive the oil viscosity and thus determine how quickly the VVC mechanism will respond. I wonder what affect using an oil which isn't 10W-40 will have?

The temperature sensor for the gauge is on the oil filter housing: I assume it measures the temperature of the oil picked up from the sump, at its coolest point.

Regards, Kes.
Kes

Kes, I may have misinterpreted the sentence in para 2 of your thread on how oil additives can clog an oil filter, but I recall that some years ago, I wanted to use a product called PLUS 101 (pronounced 1 oh 1) or something like that anyway, but I had to know whether my oil filter on my Holden Commodore would allow particles of a certain micron thickness through the filter membrane. If the oil additive has a particle micron size bigger than the oil filter, it will clog the filter and thus, the oil flow will itself, be slowed or prevented from passing through the filter. So, before using any additives in the oil of your, know what micron size your filter is and compare that to the micron size of the additive you wish to use.

Cheers,
Phil
Phil

Just as a note on temp, I already saw my oil gauge at 155° 1,5 years ago. Blew the HG & manifold, but the engine itself was still ok (well, we all know what happened 16 months later...).
On the other hand, cheapest way to have cooler oil is a K&N & bypass, which both reduce overall temp with around 5-8% (as I observed)
Dirk Vael

>bypass
Bruno,
that is a replacement for the Cat.
May get some problems with your authorities, but only if they find it out ;-)
How much MGF may be registered in your area :)
Dieter


Hi,

Unfortunately I don't know the micron size of either the MG filter or any of the additives. I would think that the Rover filter is of reasonable to good quality (around 3-5 microns, I seem to remember, is a fair filter protection).

One of the many reports on additives is at http://www.geocities.com/MotorCity/2195/snakeoil.html, and includes the passages

'..tests conducted by researchers at the University of Utah Engineering Experiment Station involving Petrolon additive with PTFE.

The Petrolon test report states, There was a pressure drop across the oil filter resulting from possible clogging of small passageways. In addition, oil analysis showed that iron contamination doubled after using the treatment, indicating that engine wear didn't go down - it appeared to shoot up.

This particular report was paid for by Petrolon (marketers of Slick 50), and was not all bad news for their products. The tests, conducted on a Chevrolet six-cylinder automobile engine, showed that after treatment with the PTFE additive the test engine's friction was reduced by 13.1 percent. Also, output horsepower increased from 5.3 percent to 8.1 percent, and fuel economy improved from 11.8 percent under light load to 3.8 percent under heavy load.'

and

'You should also note that the AA (UK Automobile Assosciation) has since also carried out tests on Slick-50 type friction reducers and concluded the same: they generally result in blocked oil filters.'

Selective quotes from articles aren't particularly fair, so as the article says at the start, read all the info, and make your own decision. You'll probably guess by now that I've made mine.

Regards, Kes.
Kes

This thread was discussed between 08/12/1999 and 10/12/1999

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