Mobil 1 good or bad????

[Guest]

I have recently become the owner of my first Porsche, a 944 Lux.
I have been advised that i should use Mobil one oil. I have also been advised to drain the existing oil, and replace with Deisel!! , run the car on idle for 5 mins and then drain and replace the filter and oil with Mobil one 0W-40.
Does anybody have any views on this, the last thing i want to do is damage the engine.

 

[chrisg]

Ian

My advice (for what it's worth) would be don't put diesel anywhere near your engine !

If you want to flush out/ clean the engine, stick the cheapest engine oil you can find (GSF or Eurocarparts or tescos) in. Run the car for ~200 miles then drain and put in Mobil 1.

You could probably get away with a good brand semi-synthetic as opposed to full synthetic.

C

 

[John Sims]

I'm with Chris.

I've never heard of using diesel as a flushing oil and wouldn't risk it myself. It's not developed as a lubricant and IMHO could do untold damage even over a short period. Either use a cheap oil for a short period or a proper flushing oil.

Mobil 1 is a very good oil but 0w/40 is too thin, you'll be lucky if it stays in the engine. If you want a fully synthetic, and who wouldn't for any other reason other than price, then Mobil 1 15w/50 is a good choice.

 

[944Turbo]

Diesel engine oil might do some good as it has lots more detergents. 15/50 would be the M1 to go for as John says,
Tony

 

[Diver944]

You could also ask the 'Oilman' for advice.

Look up Oilman in the list of members and send him an email. Simon works for Opie oils in Cornwall and offers free advice to forum members as well as good prices on the brands that Opie sell.

I can't possibly comment on the diesel advice [] but there are proprietry 'flushing' oils at motor accesory shops designed for just that job

Welcome to the forum Ian []

 

[Guest]

According to Oilman if you look in the Tech Articles, he suggests 10w-40 or 5w-40 for an S2.

 

[paulf968]

The runny Mobil 1 is too thin, as commented on by others for our 'older type' engines. The Mobil 1 Motorsport 15w-50 grade is suitable and I used it for a while in my 968. But a word of caution if you want optimum power outputs from your engine.

When I was using it I did have opportunities to do some dyno testing and found my engine about 20 bhp short of factory figures. After getting about 10 bhp back when the valves were re-seated, Hartech tried a 10w-40 and found the other 10!!!

So now I am converted to high spec 'ester' based fully synethetic from Silkolene at 5w-40 -- this will give max power & IMO provide all the protection the metal bits need. (see the posts elsewhere from Oilman)


paul f

 

[pae]

ORIGINAL: legaleagleboy

The runny Mobil 1 is too thin, as commented on by others for our 'older type' engines.

I'm intrigued by this. Is the problem simply that it might leak out, or do the manufacturing tolerances from the 80's demand something thicker. I ask because when I had my 924AS serviced they put 0W/40 in it. It hasn't leaked a drop (or consumed much) so is that all OK? Does that suggest I've got a sound engine and therefore carry on with 0W/40, or might the poor thing be suffering inside [] ?

The engine was rebuilt about 13,000 miles ago (by Paragon), so it should still be in good shape.

cheers ....... Phil

 

[chrisg]

A couple of other points to add:

1. Oil flush agents may contain additives designed to break down oil (hence remove it) and these can stay in the engine after changing the oil - not the ideal scenario.

2. To my knowledge, the best grade oil widely available = Castrol RS Racing 10 - 60w not to be confused with Castrol RS 10 -40 W (sold in BP stations). The former is available via Eurocarparts and other outlets.

With ref. to the needs for N/A engine and your 944 Lux the Mobil 1 or Castrol RS should be well suited.

[]

 

[John Sims]

To my knowledge, the best grade oil widely available = Castrol RS Racing 10 - 60w

This was my view until Simon "Oilman" enlightened me. Apparently, Castrol RS isn't a full sythetic in purists terms and only achieves the 10w/60 range by use of viscosity enhancers. These viscosity enhancers shear back under use and you end up with the equivalent of a 50 weight oil.

I used to use Castrol RS10w/60 but have now changed to Mobil 1 15w/50. Thats not quite true as last oil change they put in GTX as I didn't have any Mobil 1 available (what happened Simon?).But, as I'm loosing 1ltr ever 1000 miles I didn't think the GTX would be in there for too long if I kept topping it up with Mobil 1. [8|]

 

[usermjg]

i once had a very interesting talk about oil from a man from redline, he said there isnt such a thing as semi synthetic, so dont use them. If you are going to change your oil and filter regularly, 2 months or so then use cheap mineral oil, but if like me you intend to run the car as a second car and not change the oil so often then use good synthetic. And for flushing with diesel I wouldn't.

MArc

 

[John Sims]

i once had a very interesting talk about oil from a man from redline, he said there isnt such a thing as semi synthetic, so dont use them.

Red Line is an American product and it is the American definition of "synthetics" that has caused all the trouble and hence the confusion as to what is a true synthetic and what isn't.

At the end of the day all "synthetic oils" are mineral oil as they were all originaly black and came out of the ground. My understanding is a true sythetic is assembled from refined component parts of a certain type where as a semi-sythetic starts as black gunge, is refined until it isn't and then has extra good things added to it.

Here's a thought:- If a cheaper oil were half the price of a more expensive oil, but you changed the cheaper oil twice as often, which would be the better?

 

[Guest]

One thing to keep in mind (I haven't seen anyone else mention this, but if they have, I must have overlooked it), is that switching to Mobile One in an older car that has seen Dino Oil all of it's life could cause oil leaks.

What I mean by that is the fact that the particles in synthetics are very small, so much so that if the seals are questionable at all, the synthetic will find a way to leak out.

I switched to Mobile One (15W50) a few years back on a 72K mile motor that had previously not leaked. Within 2 months, I had leaks from the front seals and cam tower gasket. Once all of the seals were replaced, of course, no more leaks.

 

[oilman]

Perhaps this may clear up a few questions:

Mobil 1 is a true synthetic, it's a poly alpha olefin base oil, not petroleum. I still think that the perfect grade for the "older" Porsche is 10w-50.

You get the same sae 50 protection as a 15w-50 but better cold start protection with the 10w and this is where the majority of the engine wear occurrs. 10w is better for winter (5w even better) than 15w or 20w.

The Myths regarding Synthetic Oils

The benefits of Synthetic motor oils have been much debated over the last 10 years and misinformation is rife, particularly on the internet.

There are many so-called experts out there who should know better but hopefully this post will shed some light on some of the most common myths.

What are Synthetic Oils?

Synthetic Oils are fuel efficient, more fluid and resistant to thermal breakdown, they are constructed in laboratories using basestocks and special additive packages. They are specially formulated to meet and perform to standards set by API and ACEA as required by OEM's.

Synthetic motor oils damage seals.

This is untrue. Why would lubricant manufacturers build products that are
incompatible with seals. The composition of seals present problems that all types of oils must overcome.
At the end of the day, it is the additive pack in the oil that counts. Additives are added control the swelling, shrinking and hardening of seals.

Synthetics are too thin.

This is untrue. In order for an oil to be classified in any SAE grade (0W-40, 5w-40,10W-40 etc) it has to meet guidelines with regard to viscosity or thickness.

For example, any oil with a viscosity of 10W-40 has to operate at -25 degrees centigrade and 100 degrees centigrade to pass these tests or it cannot be rated as a 10W-40.

Synthetics mean higher oil usage.

This is untrue. Synthetic motor oils are intended for use in mechanically sound engines, that don't leak oil. In these engines oil consumption will actually be lower because of the lower volatility of Synthetics. They also have better sealing capabilities between piston rings and cylinder walls. Synthetics also have better oxidation stability. (They resist reacting with oxygen at high temperatures)

Synthetic Oils are not compatible with other oils.

This is untrue. The synthesized hydrocarbons, polyalphaolefins, diesters and other materials from high quality basestocks are fully compatible with other oils.

It is best to stick to the same oil for topping up that you have in the engine. It is best not to mix oils, as additives are blended for specific oils. When different oils are mixed additive pack balances can be upset so for the best performance, it's better not to mix them.

Synthetic Oils produce sludge.

This is untrue. It is a fact that they are more sludge resistant than other oils as they are better at resisting high temperatures and oxidation. Because Synthetic oils have higher flash points, they withstand evaporation better leaving less deposits.

Synthetic oils can't be used with catalytic converters.

This is untrue. There is no difference between synthetic and other oils with regards to the components. Neither will damage catalytic converters.

Synthetic oils can void warranties.

This is untrue. No major manufacturers specifically ban the use of synthetic
oils. More and more new performance cars are factory filled with Synthetic oils.
Vehicle warranties are based upon the use of oils meeting specific API Service
Classifications and recommended viscosities.

Synthetic oils will last forever.

This is untrue. There are some people that believe that synthetic basestocks themselves can be used forever. However, it is a well known fact that eventually the additives will break down and cause the oil to degrade. The additives in the oil are effectively "used up" by moisture, fuel dilution and acids. Regularly topping up the oil will help but sensible oil change periods are recommended.

Synthetic oils will protect an engine for far longer periods than non-synthetics.

Synthetic oils are too expensive.

This is untrue. It has been proven through testing that Synthetic oils do have longer drain periods and provide better fuel economy. Add this to reduced engine wear and better reliability then do the maths. They are in reality better value for money than other oils.

Cheers
Simon