DKDougherty

Good Morning All,

Newbie Porsche Boxster owner here. I am looking for engine oil usage for this car. I see several different grades in my owners manual. I live in Phoenix where it is about 100 + most of the time. This is an occasionally driven car.

As per the owners manual, I am running synthetic 5W-40 Mobil one. When I got the car, it had 10w30 synthetic Mobil1.

About two weeks after I bought it, I noticed that after sitting over a couple of hours and cooling, there was a top end rattle on start up for about 30 seconds. Following that, there is a cam follower tick when warm.

These noises got more noticeable after the switch to 5w-40 Mobil 1. Based on the symptoms here, I am thinking that I have some followers bleeding down and that I should use a thicker oil.

That said, I have had great luck over the years and in various different machines and cars with Castrol 20W 50 Non Synthetic oils. My gut tells me to switch to that and replace all of the Cam followers.


I would like to get the opinions of the noise and oil usage and engine noise before I make a decision, because I am new to this manufacturer and might not know some of the finer things about these cars ????


Thanks,


DKDougherty

Macster

Unfortunately the oil info in the owners manual is woefully out of date.

Porsche issues a technical service bulletin -- or something -- every few years that lists all approved oils for every region.

No 10w-XX, 15w-XX or 20w-XX oil is approved. Of course at least one 0w-40 oil is approved along with a number of 5w-40 oils. Even one 5w-50 oil is approved.

For an approved oil look for "A40" on the label in the section that lists what cars the oil is for.

I hope the use of 10w-30 oil didn't harm the engine. 10w-30 is too thin an oil.

The bit of rattle upon cold start after the engine has been off a while is normal. 30 seconds though is not normal. But are you sure you are just not mistaking the normal cold start harshness of the engine as valve train rattle?

The ticking noise is not normal. There is no cam follower. The cam lobes press directly down on the valve bucket. If there is a ticking noise from one of these it can be a flat lobe on the cam (rare), a "collapsed" lifter (less rare), a broken valve spring (rare).

The noise may not be from the valve hardware. An exhaust leak can mimic a noisy lifter, as can a loose spark plug. With the car new to you, and thus an unknown, a loose plug, an exhaust leak, could be the source of the noise.

That the engine had 10w-30 oil in it strongy suggests proper maintenance/servcing was probably not done and anything done has to be suspect. So this is just another way of emphasizing the noise may be from a looose plug, exhaust leak.

With the engine idling and making the noise the source of the noise should be apparent -- though maybe not readily apparent -- by careful listening using a mechanic's stethoscope at various locations. Unless you are comfortable being under a hot engine, with very hot exhaust, this is best left to a professional.

Once the location of the noise has been pinpointed then this helps you to know what's likely wrong.

It may be from a collapsed lifter but you want to know before you remove the exhaust system and the camshaft cover and the cams and replace all the lifters of cylinder bank.

For oil for your area provided you never take the car anywhere the ambient temperature can drop to -25C (-13F IIRC) consider running 5w-50. (Not a typo for 15w-50!).

Here in my area of CA winter temps are mild, hardly ever dropping below 32F for any length of time, and summer temps can climb into the 100's, which is forecast for the early/middle part of next week, so a few years ago I switched from 0w-40 to 5w-50. I have to point out though that both cars -- my 2002 Boxster and my 2003 Turbo -- used 0w-40 for a number of years/miles (the Boxster currently has over 301K miles and the Turbo over 145K miles) -- an in extreme heat with no problems. (One summer in the Boxster I ended in sourthern AZ and the ambient temperature was 116F. The engine was fine though I nearly died as it was so hot the A/C didn't work. At other times, in the Turbo west of Kingman AZ betwen there and Needles the ambient temperature was 118F to 119F. The Turbo was just fine and so was I. The A/C continued to work just fine and the cabin temp stayed at 72F with signs the A/C was working hard at all.)

You should not have to run a thicker oil to quiet the engine. If the engine is noisy with the proper multi-viscosity grade of oil in it then there is a mechanical problem that will have to be addressed.

A complication with running the wrong oil is it can result in inadequate lubrication to the engine at varioous times. For instance with 10w-30 the oil may not flow properly at cold start and at elevated engine operating tempreature may break down. The same cold start oiling concerns would arise using any 10w, 15w, or 20w-XX oil.

And there is such a thing as to thick an oil. The oil has to flow well enough that not only can it flow into the very tight gaps in the main/rod bearings, it is not so thick as the oil gets too hot from the molecular friction and break down. Also, even if the thicker oil doesn't get too hot it must also flow out of the bearing area taking heat with it and making way for cooler oil.

Additionally the cam lobes do not have oil holes to supply oil at the cam lobe/lifter bucket interface. These are lubed by oil that leaks out from around the lifter bucket at low speeds and at higher speeds assisted by splash. A too thin or too thick an oil can result in inadequate oil flow rates from around the lifter buckets and inadequate oil splash behavior at higher engine speeds and the very critical cam lobe/lifter bucket interfaces receive inadequate lubrication.

Oh, I'm not a fan of oil additives, but the Porsche techs at my local dealer advise using Swepco 502 Oil Improver for infrequently used Porsches. It helps reduce the engine rattle at cold start.

Here's a link:

http://www.swepcolube.com/products/s...e-oil-improver

I tried a bottle in each car's engine but noticed no change in start up clatter. I use my cars frequently so a car seldom sits more than a day or two unused. But if your Boxster goes days and days between uses this Swepco stuff might be just the ticket.