What Oil for a 2000 Boxster?

[raceboy]

2000 2.7 117k Mile Boxster.....
Whats the liguid gold of choice for it?
I imagine the OPC will fill it with a bucket full of Mobil 1 at a highly inflated price, if they have no objections to using my own supplied oil what is the 'experts' choice for the leggy Boxster.
As it appears to take quite a bit of the amber necter I'm guessing a good saving can be had, and every penny counts for us hard up Pork owners.

[browno]

If you've got a costco nearby get down there (or find a friendly card holder) and stock up on Mobil 1 0w/40 for £30 for 5L (versus £50ish everywhere else)... You'll need around 7 Litres for a change.

[raceboy]

Any idea if OPC's are cool with you rocking up with your own oil? ;-)

[Martian O]

raceboy said:

Any idea if OPC's are cool with you rocking up with your own oil? ;-)

Never done it, but many do this without a problem.

[raceboy]

I thought it was about 8.5l so 2 5l cans should be enough.
I've never been a massive fan of super thin oils, but if the Porsche world is anything like the TVR world you ask 5 people you get 5 different answers.
Did have a look on OpieOils and they pointed towards a 10w40...

[raceboy]

I think 5w40 could well be the future......every other car in the fleet runs on that, and it seems to work for them, and I buy that by the 25l drum.

[Martian O]

anonymous said:

[redacted]

But Opie Oils do give out wrong info as well! Make sure you get a second/third opinion before relying on Opie's advice.

[Martian O]

anonymous said:

[redacted]

Yes, a good site to get ideas from, just don't expect a correct answer from the 'experts' when you ask a question. Opie told me that a certain oil was ester based and I bought a shed-load of it because it was a good price. It turned out the experts information was incorrect and no email contact received from Opie once I pointed this out!

[raceboy]

Was talking with my TVR man today as I picked that up from it's annual service and he recommended something a bit thicker than 0W40 but to keep it within Porsche guidelines, he did have a Boxster service manual but I can't remember the specifics....
Basically any 5w40 or 10w40 that comply with ACEA A3....

http://www.opieoils.co.uk/c-915-acea-a3b4.aspx

[nickfrog]

5W40, as 0w40 is a bit thin. Mobil Super 3000 X1 is a good idea.

[tr7v8]

I've just bought a 2000 Boxster S & after a lot of reading decided it will have a heavier oil than 0W/40 & won't be Mobil 1. I've started using Smith & Allen for bulk oil & will probably use their synth which is to Porsche specs.
I'd suggest a read here: http://www.lnengineering.com/ims.html & here:- http://www.lnengineering.com/oil.html & here:- http://www.lnengineering.com/2000_Motoroelfreigabe... (which is in German but the the tables are understandable).

[TonyB66]

Mobile Super the 10W40 stuff - IIRC its the 2000

[Ian_UK1]

nickfrog said:

5W40, as 0w40 is a bit thin. Mobil Super 3000 X1 is a good idea.

There's some utter rubbish talked about oils, there really is. 0W-40 and 5W-40 are the SAME - I'll say it again, the SAME - thickness at running temperature.

Simple fact - all oils get thinner the hotter they get, so any motor oil is a hell of a lot thinner, when at running temperature in your engine, than it is cold in the can. The 'big number' part of the oil's grading is the viscosity at running temp (or thereabouts). The higher it is, the thicker the oil is at running temperature. The 'small number' tells you how much the oil thickens-up as it gets cold. So 0W-40 and 5W-40 will have the same, very-thin consistency at running temperature (as required by your engine) but as the 0W-40 doesn't thicken-up as much as it gets colder, it will appear slightly thinner in the can. More importantly, it will retain this ability to pour (and flow) easily to a lower temperature than the 5W-40. So the 0W-40 is better for your engine as it will get round all the oilways faster when cold (when most engine wear occurs) but to be fair the difference between a 0W and 5W oil is minimal in the UK climate. A 20W-40 oil would be like treacle at cold temps (and very harmful) but again, no different at normal running temp to 0W-40 or 5W-40

If you want an oil that runs thicker when hot (why you would, I've no idea, as I'll explain in a moment) you need to go for a 0W-50 or 5W-50. a 5W-50 will be the same thickness in the can as a 5W-40 but will thin-out a little less as it heats up to running temperature.

So why are thicker oils (at running temperature) generally a bad idea? Your oil system can be likened to a tube with a positive displacement pump pumping oil in at one end and a small(ish) hole at the other for the oil to escape through. The hole is the equivalent of the bearings and other oil apertures in your engine. In the middle of the tube is a spring-operated valve (the oil pressure relief valve in your engine). As the pump speed increases with engine rpm, the pressure in the tube increases as the pump starts to move more oil than can escape through the hole at the other end. The relief valve then opens to keep the pressure from going over a preset value. If you now thicken the oil, the amount that can flow through the hole for a given pressure DECREASES but the relief valve still opens at the same pressure. So you will get your max oil PRESSURE coming-in at slightly lower rpm, but at the cost of oil FLOW (together with the cooling and lubrication it provides) around your engine. So not the best idea in the world.

Hope the info is of some use.

[eagle1]

It is a bit more complex than that - I would read some of the stuff on the Hartech site which explain why a slightly thicker grade oil is recommended for these engines. The one thing I would be sure to do is to make sure that you change the oil every 5000 miles max as the newer Mobil 1 oils don't have the same amount of ZDDP anti-wear components in them, and cause premature wear (which may contribute to the infamous IMS problem) although help not to cause probs with the cat.

[sundayjumper]

The couple of times I've used 0W-something oils they've turned minor leaks into bigger leaks, I assume because they're thinner when cold and gets past seals a bit more easily. I'm not a fan of that and stick to 5W40 where possible.

[Ian_UK1]

sundayjumper said:

The couple of times I've used 0W-something oils they've turned minor leaks into bigger leaks, I assume because they're thinner when cold and gets past seals a bit more easily. I'm not a fan of that and stick to 5W40 where possible.

But either is a million times (well not quite) thicker when cold than hot. If the oils don't get past the seals when they're hot and very thin, why would either get past them when they're cold and both/either are a LOT thicker than when hot?

[Ian_UK1]

eagle1 said:

It is a bit more complex than that - I would read some of the stuff on the Hartech site which explain why a slightly thicker grade oil is recommended for these engines. The one thing I would be sure to do is to make sure that you change the oil every 5000 miles max as the newer Mobil 1 oils don't have the same amount of ZDDP anti-wear components in them, and cause premature wear (which may contribute to the infamous IMS problem) although help not to cause probs with the cat.

The time when thicker-when-hot oils can potentially help is (to use my earlier analogy) when the hole in the open end of the pipe gets bigger - i.e. worn bearings in a high-mileage engine. In this case the thicker-when-hot oil will flow out the larger hole at the same rate as the thinner oil does out of a smaller hole for the same given pressure. This can go some way to restoring the operating parameters of the engine's oiling system.

In truth, oil quality is probably more important than (hot) viscosity in protecting an engine (assuming the hot viscosity isn't too high to maintain the required oil flow at the design pressure). Cold viscosity is very important in protecting the engine - the thinner the better, so it gets to where it's needed the quickest.

[tr7v8]

Ian, a lot of the very thin oils (when cold &/or hot) are spec'd to get the absolute best fuel consumption figures. Fine when cars are brand new, complying with legislation & most importantly when someone else (company or lease) picks up the tab when it goes bang. Also whilst they still have their very fine clearances which enable thinner oils.
The links I referred to above & others state that IMS bearing failure is exacerbated by A. short runs B. Gentle driving & C. oils that are too thin.
The reason that a lot of people experience increased oil leakage when using the very modern low viscosity (when cold or hot) is that oil pressure is MUCH higher when cold than when hot. Thus seals that are not in their first prime will leak when subject to high pressures of a thinner oil. Another issue on the M96 engines is bore scoring which generally points to oil break down at high temps.
Other issues are the drop in the latest SAE & API specs of Zinc & other high pressure additives which are causing issues with cams etc.
So based on this knowledge & research mine will be running heavier weight oil than it originally left the factory with & that whoever services would typically use in servicing. In other words I'll provide it!

[eagle1]

Ian_UK1 said:

In truth, oil quality is probably more important than (hot) viscosity in protecting an engine (assuming the hot viscosity isn't too high to maintain the required oil flow at the design pressure).

I agree and as Baz Hartech has explained many times quote - The idea that oil thickens up when it gets hot is in my experience wrong. I think the claim is that it works as well as higher grade oil when hot but this doesn't take into account that when bearings wear the lateral clearance is greater so the oil has less resistance to squeezing out the side of shells etc and therefore does not support the bearings as well. Similarly if the oil is a thicker grade it usually is thicker when hot and I have had my amateur ideas discussed with technical oil racing experts from Mobil and Castrol and both agree with my general view – end quote.

[Ian_UK1]

tr7v8 said:

The reason that a lot of people experience increased oil leakage when using the very modern low viscosity (when cold or hot) is that oil pressure is MUCH higher when cold than when hot.

So the oil pressure relief valve does what then....? Cold oil just gives you the same effect (but much more of it) as using an oil that is thicker at running temp. The oil pressure is higher at low flow as the oil can't excape throught the 'outlets' so easily. But the ultimate pressure is governed by the relief valve. If the relief valve opens at 75psi hot, it opens at 75psi cold too. Whne the engine oil is cold, the flow to the bearings at 75psi is much lower than the flow of hot (or thinner-when-hot) oils at that same 75psi.

Think of it this way. Why are we all advised not to give an engine the beans until the oil's hot? By your statement, oil pressure is BETTER when cold so surely that's a good time to rag the motor? But it isn't - we all know that - and the reason is that the oil FLOW is insufficient when the oil's thick (due to temperature or grade or both). It's oil FLOW that continuously replaces the oil molecules in the film and is responsible for cooling of bearing surfaces etc. Given a sufficiently large pump, flow is determined by pressure, viscosity and the size of the aperture out through which the oil flows.

Edit: Finally, your statement above makes no sense as oil seals aren't under pump pressure - so aren't affected directly by oil pressure. Even a major seal such as the RMS is effectively just a 'splash' seal. As oil flow is much lower when the engine oil is cold, it will have less oil splashing against it to be retained, not more. Also bear in mind the crankcase is under partial vacuum during normal running - something that would tend to help keep oil in the engine, not the other way around.

Edited by Ian_UK1 on Monday 14th May 09:32