Recommended engine oil ? yes, that old chestnut !

[Guest]

Hi Folks,

Can anyone offer any advice as to what the preferred type/make of engine oil for an '86 944 2.5 (8 valve) is ?

I guess this question has been asked many times before but having done a forum search I couldn't find a definitive answer.

I've only had my porsche for about a month and had to get some oil to top it up. I went down to halfords and plumped for Castrol 15W40 part synthetic oil, which was recommended on their car/oil chart, my 944 owners amnual was a bit vauge and just said use a quality mineral oil.

Looking through old threads it seems its ok to go with part synthetic oil rather a mineral oil. Is there any particuler brand of oil Porsche owners go for ?

Cheers for any advice.

 

[Diver944]

There is no favourite - we all have our own preferences.

The owners manual shows that a wide range of viscosities are sutable for your model and the viscosity slap bang in the middle is 10w40. A true synthetic is more resistant to breaking down due to heat so is only really necessary for hard used Turbos

You will be fine with 15w40 of a known brand, just make sure its changed regularly

 

[sawood12]

You should also consider your driving when cold. If you are hitting a dual carridgeway or motorway within about 15 or 20 minutes of your journey every day then go for a low W rating as this will give you much better cold protection. Ideally go for an Ester oil that is clingy like Magnatec to give you the best cold start protection. Given that virtually all the wear of your engine occurs when it is cold in the first 15 - 20 minutes of any journey the best cold protection you can get the better. Once the engine and engine oil is warm there is virtually no engine wear at all. I tend to hit a dual carridgeway within a few minutes of most journeys and although I try my best to keep the revs below 3k and stay off boost sometimes it is not always possible in rush hour traffic on the A50 which is more like the Nurburgring most of the time!

 

[944Turbo]

Silkolene Pro R or Pro S - as good or better than moil 1 but cheaper,
Tony

 

[peanut]

ooooooooooh nooooooooo not the oil sketch again ( Monty Python voice)



Its not the quality of the oil thats important imho its keeping it changed regulary ie every 10-20k miles along with a new oil filter.

 

[333pg333]

I won't get drawn into my opinion, but it is not the cold startup that does the damage, it's the under load part. So as Scott advised, don't 'get on it' until the oil temps rise satisfactorily.

 

[zcacogp]

ORIGINAL: peanut
Its not the quality of the oil thats important imho its keeping it changed regulary ie every 10-20k miles along with a new oil filter.

Absolutely. Spot on that man.

My only comment would be to make it nearer a 5k mile change - leaving it in for 20k sounds far too long to me.

Cheap oil changed regularly is a much better bet than expensive oil changed infrequently.


Oli.

 

[smitty893]

Cheap oil[:'(] doesn't (IMHO) belong in anything other than a cheap banger. Modern synthetics can quite easily last 10/12000 miles and will protect your engine much better for that little extra cost.

 

[Diver944]

ORIGINAL: smitty893

Modern synthetics can quite easily last 10/12000 miles and will protect your engine much better for that little extra cost.

100% true. []

But, in our old engines the filter can still get very clogged and even worse moisture can get in to the system. It doesn't matter how brilliant your oil is if its contaminated with water on your bearings []

Stick to oil changes every 6 months or 6k miles whichever comes first IMHO

 

[sawood12]

Even expensive oil is relatively cheap in the grand scheme of things so why not get the best you can? It's a false economy to do anything else. Modern synthetic oils are leagues ahead of anything that was available 20yrs ago when our cars came off the production line and even in our old engines a modern synthetic oil will give you much, much more protection than a cheap oil. Testiment to this is that a 997 is on a 15 - 20k oil change interval. If you are using a good quality fully synthetic oil then a 6k service interval is perfectly appropriate and safe as the oil is more resistant to contamination from water and other hydrocarbons.

 

[zcacogp]

Sorry, should have justified "cheap". I was trying to convey the sentiment that it's better (IMHO) to spend less on the oil and change it more often than to spend lots of money on super-duper expensive stuff and change it less frequently.

I happen to use 10W40 (I think) semi-synth from a GM dealer. It's very high spec and very good value. And I change it every 5k miles. (Obviously, in an ideal world, I woul duse Mobil 1 and change it every 5k miles, but that wouldn't be permissible for a number of reasons ... think wife and Bank Manager.)

I'd rather do this than spend 3x as much on the oil and change it a third as often. Oil collects contaminants, and by changing it you dispose of those contaminants. I don't want them in my engine longer than strictly necessary.


Oli.

 

[Jonny B]

Im off out to buy oil and filter now and changing today, its been a yr and nearly 4k on the clock since it was last done, last yr i spent £75 on oil for 9 or 10ltrs i think, used the rest to top up over the year. well the excess lasted about, 8 months, seemed quite a lot, does that sound normal to you guys?
Im hoping to find silkolene somewhere but dont know where my local stockist is, im in preston.
JB

 

[Guest]

So going from what some people have said I could even use a full synthetic oil or is that for more demanding turbo engines ? Looks like a good compromise for money/performance is a part synthetic oil like castrol coupled with regular changes as previously advised.

 

[zcacogp]

ORIGINAL: chrisjt74
So going from what some people have said I could even use a full synthetic oil or is that for more demanding turbo engines ? Looks like a good compromise for money/performance is a part synthetic oil like castrol coupled with regular changes as previously advised.

It's all a matter of what you want to spend, as far as I can tell. Thinner oils tend tobe fully synth, and fully synth oils are no doubt better than semi-synth, or mineral. BUT, do you need that degree of technology in your oil for what is a fairly primative engine? Sure, if you have a modern high-revving motorbike engine being revved to bu99ery on a racetrack, which is running everything to pretty high tolerances, you may do well spending lots of cash on a very high-spec fully-synth oil. If, on the other hand, you have a 20-year-old engine which is producing low bhp/cc, and not being thrashed constantly, do you need to pay for the best oil out there?

In my book, a good semi-synth changed often works fine. As with everything, the prive/performance curve gets much steeper towards the right hand end and I don't need to pay that much more for slightly more performance.

I believe that the 944 was designed to run on plain mineral oil when it was first designed, but could be wrong. On that basis, anything semi-synth is a BIG step up. (Oh, and also bear in mind that oil distributors are not disinterested parties in this discussion.)


Oli.

 

[Guest]

This is where the various bits if advice start to conflict, I originally posted becuase I wasn't sure if I could substitute the recommended mineral oil for a more modern semi-synthetic.

As you said I wonder if it should just be run on a mineral oil as nature intended ?

 

[zcacogp]

ORIGINAL: chrisjt74

This is where the various bits if advice start to conflict, I originally posted becuase I wasn't sure if I could substitute the recommended mineral oil for a more modern semi-synthetic.

As you said I wonder if it should just be run on a mineral oil as nature intended ?

Good questions all ... I suspect that you will get two forms of answer - opinion (as my answer is), and sales spiels.


Oli.

 

[944Turbo]

Difficult to get impartial advice on oil - oil vendors want to sell it to you, garages (some anyway) want to do work on your engine.
I do know that after 80k miles of abuse by me on mobil 1 and silkolene my bores were virtually unmarked - I also know that despite high mileage 180,000+ and regular bouncing off the limiter my car is still one of the most powerful 2.5s in the uk at 18psi.
I dont know what oil the previous owners put in or how they treated the car.

I also know when I swapped my 1380 mini to mobil 1 on the advice of a local mini racer it lasted over 4 times as long as when running the best castrol or duckhams oils of the time.

I get my silkolene from turbo dynamics in christchurch - good price but I can collect, not sure how much to mail order it.

Tony

 

[sawood12]

I would say that all engines N/A or turbo charged should run on fully synthetic. Forget so called Semi Synthetics - they are a marketting exercise and technically they should be considered to be, to all intents and purposes, mineral oils. Also I think it is a bit of a myth about engines being designed for mineral oils. I'm not sure how you would design an engine differently for mineral oils than for fully synthetic oil. You design the engine based on a number of tecnical and economic criteria and select the oil to suit. Designing an engine to suit an oil is a bit like the tail wagging the dog. Also IMHO the age of your engine is irrelevant. If you had a Model T Ford then a fully synthetic will still be a far superior oil to use than a mineral oil. Mineral oils have no advantage whatsoever over a modern fully synthetic. Also a 40 grade fully synthetic oil is exactly the same viscosity as a 40 grade mineral oil, semi-synth oil or even a 40 grade low fat spread for your toast in the morning.

As far as the 944 handbook is concerned when it comes to oil throw it away. The relentless march of technical improvement means that modern oils especially fully synthetics, have come a long way over the last 20 - 25 yrs. I'm sure if Mobil 1 or Silkolene Pro S existed in 1987 then Porsche would have approved it for use in the 944 Lux as well as the 944 turbo just as they do for the 997C2 and the 997GT3 (which revs to 8k rpm) and the 997 turbo.

In terms of cost - you can get 4ltrs of Mobil 1 from Costco (0w40 only unfortunately) for £20 so you can't say that is poor value for money. I use Silkolene Pro S as it is an Ester oil (Mobil 1 isn't) and that is £40 for 5ltrs from Opie oils which is expensive but a full tank of petrol is £60 and I get through at least one a week so relatively speaking it still isn't that expensive. I've not yet found another cheaper supplier than Opie, Silkolene seems to be pretty dificult to find.

 

[smitty893]

If you are struggling to find Silkolene oil try a Kawasaki motorcycle dealer - they tend to recommend it []