which Oil, Mobil 1 ?

jam1976 · Jan 17, 2006

Not had my 911 long (1989 3.2), its now due for its annual service, chatted to my local porsche specialist who suggested Mobil 1 is not the correct oil for a 3.2, too thin.
b4 i bought my 911 it had just been serviced using mobil, i can see this from the invoice's i have. Do i go down the semi synthetic route as my specialist is suggesting or stick with Mobil 1. I want the best for my 911, since i've owned it i haven't noticed any leaks, if this should have any bearing on your recomendations.
I would appreciate any advice!
What oil would have been in it when it left the factory ???
Mobil 1??

wormand · Jan 17, 2006

I was told the same story. Mine has semi-synthetic in it every year now. I'd rather not have any leaks appearing and for the miles I do each year (1500 ish) its as clean coming out as it goes in. I always make sure that when I do use the car it goes for a proper run, gets nice and hot before tucking it back in the garage. Stick to a good brand of semi-synthetic and you can't go wrong. Where are looking to get a service??

Chris_911 · Jan 18, 2006

I use a Millers fully synthetic grade (can't remember the number) recommended by Francis Tuthill who do the annual servicing for me.

It's a heavier weight than the Mobil 1. No problems or leaks to report.

Guest · Jan 18, 2006

ORIGINAL: jam1976

Not had my 911 long (1989 3.2), its now due for its annual service, chatted to my local porsche specialist who suggested Mobil 1 is not the correct oil for a 3.2, too thin.
b4 i bought my 911 it had just been serviced using mobil, i can see this from the invoice's i have. Do i go down the semi synthetic route as my specialist is suggesting or stick with Mobil 1. I want the best for my 911, since i've owned it i haven't noticed any leaks, if this should have any bearing on your recomendations.
I would appreciate any advice!
What oil would have been in it when it left the factory ???
Mobil 1??

Your specialist is right. Most every specialist will recommend a semi-synthetic. Many suggest Castrol Magnetec for the extra cold start protection. The best protection is to change the oil and filter more often, don't get too worried about Mobil 1.

Because mine if freshly rebuilt and it is mainly used on track , I use Castrol RS synthetic but the cost is outrageous. I previously used Magnatec changed every 3-4000 miles sometimes less.

Guest · Jan 18, 2006

I was told to use Castrol RS as it helped with oil consumption, but if I dont intend to track day it, am I better using a semi synthetic for road use and make sure it has Castol RS in it when I do ?

twinny · Jan 18, 2006

Go for a good quality semi-synthetic. I've just changed over to Millers Classic Sport for the winter oil change after some issues I had with oil that was too thin put in after a clutch change. I went from bone dry to "Tory Canyon" due to modern thin synthetic oil. Problem resolved now after a long chat with the Millers team at last years Classic Car Show at the NEC. Not a bad price either and my oil pressure has come up 0.5 bar across the board, back to where it used to be.

Bazgillie · Jan 18, 2006

I had Mobil semi in my SC and it found its way out far to easily so I have now got Magnatec in it and it has quietened the engine down a lot, still leaks a bit but that is from the oil return tubes.
Baz

38F3E1 · Jan 18, 2006

Is your specialist arguing against Mobil 1 or against fully synthetic or is the advice based more on the correct viscosity they feel you should put in the engine(5w-40 vs 10w-40 vs 15w-50 etc) ?

You can get good full synthetics in all the viscosities that might be recommended. I run an old 1973 E and it runs on fully synthetic no problems (and I use it on the track too). I have had experience with both Silkolene and Motul full synthetics in older cars. Fully synthetic does not automatically equal leaks (as your car has proved).

I would not discount fully synthetic (of the correct grade) unless price is an issue.

Ian.

Anil · Jan 18, 2006

I had used Mobil 1 0w/40 for the past 4 yrs with no issues at all in my 3.2. For my last service I switched to Castrol RS10w/60 and there has been no difference in oil consumption between the two, and no leaks.

I did notice, however, that the engine temperature remained a lot lower when using the 0w/40 oil during the summer months.

I managed to get several packs of Castrol RS 0w/40 at half price from Halfords over the summer, and I plan to use that for its next service.

I wouldn't get too hung up on the different viscosities. As Richard has stated, regular oil and filter changes are the key to a healthy engine.

Cheers

Anil

jamescharnley · Jan 18, 2006

ORIGINAL: ian_uk

You can get good full synthetics in all the viscosities that might be recommended. I run an old 1973 E and it runs on fully synthetic no problems (and I use it on the track too). I have had experience with both Silkolene and Motul full synthetics in older cars. Fully synthetic does not automatically equal leaks (as your car has proved).

I would not discount fully synthetic (of the correct grade) unless price is an issue.

Ian.

I'm with Ian. I have used both Mobil1 & Sikolene fully synthetics in my 1973 2.4S without problems. I'm going to be using the 'heavier weight' Mobil1 at my next service

TopCarrera · Jan 18, 2006

I've used synthetic (various brands, mostly Mobil1) and never had a problem. Previously with older cars (Alfa Romeos and Lancias) I found that synthetics did tend to promote some minor leaks. There are various viscosity grades of synthetic and if you choose a"heavier" grade you should be OK.

If you are extending the car (trackdays) I would always use a synthetic oil. You simply cannot get comparable performance and protection from a conventional mineral or semi-mineral based product. IMHO avoiding wear is preferable (albeit with the occasional steam cleaning bill for minor leaks) than any increased engine wear. There is a lot of b***s**t touted regarding all sorts of go-faster goodies and general boy racer merchandise on the market but the pros of synthetic oil are real, proven and based on simple chemistry and tribology.

I'm sure the following will promote some debate but have you considered using one of the numerous additives featuring dispersed solid lubricant (usually Molybdenum disulphide) e.g. Slik 50? Again the science behind these products is genuine and straightforward - I swear by the stuff! My first experience of these products was many years ago when I witnessed a colleague of mine add a few hundred ml of Slik50 to his Alfa Guilia and notice tickover rise by a few hundred rpm! I immediately bought a pack and experienced exactly the same effect when I added some to a Lancia Gamma Coupe I had at the time. Every vehicle of mine has always had this treatment.

Guest · Jan 19, 2006

ORIGINAL: TopCarrera

I've used synthetic (various brands, mostly Mobil1) and never had a problem. Previously with older cars (Alfa Romeos and Lancias) I found that synthetics did tend to promote some minor leaks. There are various viscosity grades of synthetic and if you choose a"heavier" grade you should be OK.

If you are extending the car (trackdays) I would always use a synthetic oil. You simply cannot get comparable performance and protection from a conventional mineral or semi-mineral based product. IMHO avoiding wear is preferable (albeit with the occasional steam cleaning bill for minor leaks) than any increased engine wear. There is a lot of b***s**t touted regarding all sorts of go-faster goodies and general boy racer merchandise on the market but the pros of synthetic oil are real, proven and based on simple chemistry and tribology.

I'm sure the following will promote some debate but have you considered using one of the numerous additives featuring dispersed solid lubricant (usually Molybdenum disulphide) e.g. Slik 50? Again the science behind these products is genuine and straightforward - I swear by the stuff! My first experience of these products was many years ago when I witnessed a colleague of mine add a few hundred ml of Slik50 to his Alfa Guilia and notice tickover rise by a few hundred rpm! I immediately bought a pack and experienced exactly the same effect when I added some to a Lancia Gamma Coupe I had at the time. Every vehicle of mine has always had this treatment.

Lucky you [

][

]. The leaking ain't just a theory, many have had leaks start or worsen when changing to thinner fully synthetic. All your points are good but people should be aware of the risk in changing to fully synth.

I still think semi-synth like Magnetec changed frequently will give you all the protection you ever need - even for track days probably. If you are checking the old oil and it looks like new when it comes out and if you cut the filter open and it looks like new, I think you have pretty convincing evidence that there is no wear. My mechanic described my engine as "looking like new" (other than valve guides) when it was opened for surgery. At 80,000 miles it used zero oil before surgery.

Just my $0.02 - I am no expert, engineer etc

944Turbo · Jan 19, 2006

ORIGINAL: Richard Bernau

Lucky you [][]. The leaking ain't just a theory, many have had leaks start or worsen when changing to thinner fully synthetic. All your points are good but people should be aware of the risk in changing to fully synth.

I think the point there is 'thinner synthetics' Synthetics are available in various grades just like mineral oils.
There is no reason why a 15w50 full synth should leak any faster than a 15w50 semi synth. The full synth should provide better protection and stay in grade longer.

Tony

jam1976 · Jan 19, 2006

ok, lots of idea's. but what shall i use ? is mobil 1 ok ? when the porsche specialist say's 3.2's wern't designed for mobil 1 what does he mean. its got mobil stickers all over the engine bay !! Not particulary bothered about the cost of the oil only do a few thouand miles per year, summer only ! planning european blast this year, interesting to hear fully synthetic run cooler. what would the porsche engineers in stuttgart say, it left the factory in 1989 with?????

38F3E1 · Jan 19, 2006

The most important question is what weight of oil to use in the engine.

5w-40, 10w-40, 15w-50 ...........

sawood12 · Jan 19, 2006

And there is no difference at all between 0W40 and 15W40 once the engine is upto temperature. The '40' refers to the viscosity of the oil so when warm so both of the oils will have a viscosity of 40. I think the W stands for 'Warm' and not 'Weight'.

For cold start protection I think Ester oils are the way to go as they are polarised (just like Magnatec). I run 5W40 fully synthetic Ester oil in my 110k mile 944 and it doesn't use any oil - not even the 1ltr per 1500 miles as suggested by the handbook. However I can't think of any reason not to use a fully synthetic oil. Why on earth would a semi-synthetic oil be a more suitable oil to use? Aparently semi-synthetics such as Magnatec contian such a small content of synthetics they are practically purely mineral.

You should refer to Oilmans notes in the oil forum at the bottom of the 'All Forums' page to get all the technical detail on oils you could ever wish for!

Guest · Jan 19, 2006

ORIGINAL: Chris_911

I use a Millers fully synthetic grade (can't remember the number) recommended by Francis Tuthill who do the annual servicing for me.

It's a heavier weight than the Mobil 1. No problems or leaks to report.

Fran changed the oil in mine last year and we went from Mobil 1 to whatever he uses. The car was immediately slower when on a warm-up idle from cold, doesn't sound 100% happy to me on whatever is in the oil tank. It has also used a litre of oil so far this year (3200 miles) where it used about a half a litre or so in 6000 last year. Cannot explain this but there you go. I had no problems on Mobil 1 and I'll definitely be switching back next service to see if it makes a difference.

twinny · Jan 19, 2006

ORIGINAL: sawood12

And there is no difference at all between 0W40 and 15W40 once the engine is upto temperature. The '40' refers to the viscosity of the oil so when warm so both of the oils will have a viscosity of 40. I think the W stands for 'Warm' and not 'Weight'.

For cold start protection I think Ester oils are the way to go as they are polarised (just like Magnatec). I run 5W40 fully synthetic Ester oil in my 110k mile 944 and it doesn't use any oil - not even the 1ltr per 1500 miles as suggested by the handbook. However I can't think of any reason not to use a fully synthetic oil. Why on earth would a semi-synthetic oil be a more suitable oil to use? Aparently semi-synthetics such as Magnatec contian such a small content of synthetics they are practically purely mineral.

You should refer to Oilmans notes in the oil forum at the bottom of the 'All Forums' page to get all the technical detail on oils you could ever wish for!

The "W" refers to the winter viscosity measured at low temperatures (below 0 degrees C). The 40 refers to the viscosity when hot (above100 degrees C).

Most engine wear is generated at start up (cold in particular) so the oil you choose should reflect the type of use your car gets. Mine is started and warmed up before driving a decent distance, If I were using it everyday, stop start I would probably use a different oil, but what I have now is fine for my use. Most people say that a good quality 10w-40 semi-synthetic will do just fine. If your worried about leaks move up the viscosity. It is generally thought that 0w or 5w oils are a little too thin for 20 year old engines from cold, but you will always find somebody who takes the opposite view.

If your worried about cold start wear run with an additive to give you some protection, but I wouldn't worry about it greatly unless your doing stellar mileage. Most of us I guess are doing 5000 miles a year with one or maybe two changes. Any reputable manufacturers product should not be an issue in such cases. Porsche don't list Mobil 1 in the handbook to the best of my knowledge, I think the product has been hyped up. Maybe it performs fantastically in modern Porsche engines where tolerances are much more carefully engineered, I don't think it makes a huge difference in the real 3.2 world.

sawood12 · Jan 20, 2006

Surely no matter what your type of driving - high milage, low milage, short runs, long motorway milage - the vast majority of any engine wear (somewhere in the region of 80 to 90%) occurs in the first 10 to 15 minutes of your journey. The ratio of milage to number of start ups will only determine your wear rate, however on this basis it makes common sense to me that whatever oil you choose to run it's best to choose an Ester oil which greatly reduces the wear rate in that crucial 10 to 15 minute warm up period. Mobil 1 is not an Ester oil.

twinny · Jan 20, 2006

That's what I was saying. I don't do a lot of stop/start journeys, if I did I would probably change my oil to an ester based product to reduce the potential of start up engine wear. As I don't I run a good quality semi-synthetic and change it twice a year.

I would say that for drivers on limited mileage policies with a 2nd car type driving profile any good quality 10w or 15w-40 from a reputable manufacturer should be fine. I personally wouldn't use Mobil 1.