oil

on topping up my oil level (after 2000m) i noticed a creamy emulsion at the top of the oil filler tube (where the dipstick goes in). is this normal? Should I be speaking to the dealer? Any advice appreciated. vimal nov 2002 C4S

Hi Vimal I have got this too, with similar mileage - I suspect it is something to do with an additive in the oil (I seem to remember reading somewhere that there is something that acts like a detergent (?!)). However, I have this in the filler tube, not where the dipstick goes in. I am not worried about it unless there is a serious build up which would suggest water in the oil... Any problems with your radio yet? Regards Ian (C4S - September 2002!)

Hi Ian It' s actually at the top of the filler tube not the dipstick bit (its been a week since I looked at it!) I have arranged to take it into the OPC for them to have a look - they say it shouldn' t be a problem but its worth checking just in case. My radio went a week after I got the car - I had to wait almost 3 weeks for a new amplifier - apparently this was a prob with all the C4s cars built around the same time. Since then its been fine although I find it very tinny compared to my previous 996 (2001 MY). I have the standard sound package on the C4S (i.e. not bose and had the same sound system on the old car). How do you find the sound in yours? Regards Vimal

Having read your posts I thought I would check my car as well (Sept 2002 996 C2) and it has the same creamy substance around the oil filler tube as well. I guess unless all 996' s have leaky head gaskets it must be OK. I would be iterested to hear what your OPC says though

I have got the standard sound package and find the sound fine - not as good as the sport exhaust though[ ] The amp problem sounds interesting - on mine the whole thing fails to work intermittently but returns after locking/unlocking the car and seems to reset. It is in again tomorrow; I have been waiting three MONTHS for a fix! I will ask about the oil too... Apparently there is a manual on the various problems with this year' s sound package (some Boxsters have been affected too). Regards Ian C4S

Mayonnaise -usually suggests lots of short journeys...... Melv

My dealer reckons it is condensation - primarily due to short journeys. I need to get out more! The radio problem was diagnosed - to a faulty amp. Unfortunately the speakers are cutting out intermittently with the replacement... Regards Ian C4S

944' s also do this A LOT at this time of year because of their tall filler neck. I know our engines are totally different but the cure from the 944 Register is to very slightly loosen the filler cap. This allows a bit of ventilation and stops the condensation forming. I have no idea where the 996 filler is so please don' t follow my amateur advice if it means oil will slosh everywhere [ ]

Guys, Checked the oil filler of my C4S last night, no mayonnase, mines still being run in and has only done 1,000 miles and all journeys have been over 25miles. I' ve also managed to keep the average speed since collection over 40mph and I' ve done very little motorway driving. No problems with the radio but I find the sports exhaust much better entertainment. The fact it goes quiet between 30mph and 45mph is a great safety feature, it means you keep below 30mph in villages and built up areas and just enjoy the noise. For those of you who have not seen the mail I posted in the ' track day section' I' ll repeat the results of a noise test I had the marshalls at Goodwood do on Saturday, I popped in on spec and there was a track day going on so I just asked the marshalls to test my car. At 5,200 rpm it was 107db on sports setting and 102db with the quiet button in so clearly track day friendly except maybe Castle Combe, but I seem to recall they did the test at 4,500 rpm, I' m sure that will knock of 2db, I' ll find out on the 19th April when as my first track day in the C4S there and its a 100db day. Regards

Kevin, I am also booked into the Castle Combe day on 19th April (it' s my birthday [ ]) with my 944 Turbo. I would be very interested to see a demo of your adjustable noise sports exhaust (in the paddock of course). There are some American companies who manufacture a similar sounding device for my car, but it' s nowhere near as swish and modern as your ' touch of a button' one sounds. In fact it' s very heath-robinson, with a diverter pipe that just vents to atmosphere before the catalyst. I imagine it' s very loud [:' (]

If you are taking it to an OPC then they will only want to fill with a Porsche Approved oil. If you want a copy of the list, email me and I'll attach it to a reply. Approved Castrol Oils are: Castrol Formula RS Power and Protection 0 W-40 Castrol TXT Softec 5W-40 CastroI GTX 7 Dynatec 5W-40 Castrol Performance 5W-40 Castrol Syntec 5W-40 Castrol Formula RS Road and Track 5W-40

its going into jz machtech

Any Porsche Approved 5w-40 will be fine. You can also use 0w-40. Cheers Simon

You'll need 9 litres, which used to be awkward as it came in 4L containers, but I think they now have it 5L containers.

i went to costco today and bought 12 lires as i asked this question last week. u need 10 litres im told and they sell it in 4ltr containers. 8 litres in costco was £50 and im supplying my own for next service next week. Im guessing that ill get back a container with 2ltrs left in it. bit of a pain they dont do it in 5ltr tanks

The actual capacity is 10.25 litres, but the change quantity is stated as 8.25 litres. Shame the new 5L containers haven't filtered there way into Costco yet.

They will give you the 2ltrs back, but it will come in handy for top-ups.

none at all, very little difference between the two, the 0-40's slightly more fluid at 0deg. C, with a 50/50 mix you'd end up with say 3-40.

I think the key thing is that they are both the same types of oil - ie fully synthetic or part synthetic. I believe the 2 may not mix well & then you may lose significant oil performance. By the way, the first part of the rating is the high temperature performance NOT the cold performance - ie 0-40 has very low viscosity when hot & 5-40 has slightly higher viscosity when hot. Both oils have the same "40" viscosity when the engine is cold. Very low viscosity is great for performance & getting the oil to all the critical bearings very quickly after start-up, but is potentially not good for bearing life or leaks. High viscosity gives lots of bearing protection when it finally get there, but creates "drag" which reduces performance & mpg. Paul 2004 996 C2 40 Anniversary

Sorry Paul, but i think you have got that the wrong way round. Both 0W-40 ant 5W-40 have nominally the same viscosity when hot. 5W is thicker than 0W when cold.

Many thanks guys, i always use fully synthetic and will therefore use up what i have first. Always used mobil 1 but for some reason the service used valvoline!!! I want to ensure i continue with mobil 1 so will use what i have, thanks for the technical info, David

Hi Richard, So, is the "5W" part of the rating measured on a different scale from the "40" part? - because obviously the oil must be less viscous at high temperature. This has always confused me about oil ratings. But like you I have always understood the "W" part to be the Winter viscosity. Or does "-40" means "minus 40"?! Mark

The first number is the viscosity at 40 degrees C, and the second is at 100 degrees C. The "0W", "5W" and "40" are in fact ranges. When comparing viscosities of oils, it is best to compare the kinematic viscosities in CentiStokes, which is a true value for the oil's thickness. Hopefully this chart will make it a bit clearer:

Here is a table I made some while ago from oil datasheets. You can see that because "0W" and "5W" are ranges that overlap, you can get a 5W oil that is actually thinner than a 0W at 40C.

Richard, You're right, I hadn't understood the oil ratings correctly. However, after your last post I think I understand ! Your last chart shows what I expected, that all of the oils have higher viscosity cold than hot - which I guess most people would intuitively think is right - hot oil is "runnier" (to use the technical term !). I'd therefore (incorrectly) assumed that the lower rating must indicate the hot viscosity. From what you've explained & shown in chart in your first post, the rating for hot & cold viscosity is totally different - even if the viscosity is still measured with the same Cst units. Its good to learn something new every day ! Paul 2004 996 C2 40th Anniversary

Very interesting. In that case you really can't compare between brands on viscosity - only within the Castrol brand (the only brand with more than 1 oil in the table) is there any relationship between the viscosity and the ratings. I'd be interested to see the viscosity figures for Mobil 1 5W-40 if anyone has them to compare with the 0W-40, but only out of "interest" - I'm not sure that I'll do anything different![8|]

I got the info in the table from datasheets on the Opie Oils site, and from manufacturers sites. You are right, it is very difficult to compare brands. Mobil 1 0W-40 is thicker than a Castrol 5W-40 in both hot and cold ranges.

omg, I didn't realize my post would get so technical. You guys certainly know your stuff. It will take a little longer to sink in with me but thanks all the same.

@ 6k I would be changing the oil not topping up?. 5w-40w I use Miller or Fuch from Opie.

If the cars got a few miles on i'd be contemplating a 10W-50, i use Millers full synthetic. Tim '02 C2 Cab 60k miles

Hi guys, thanks, are you saying you change oil every 6K, including filter? Thought service schedule was up to 12K? Had never heard of Miller but had a quick look and seems decent enough Bst Andy

Hi Andy, For what it costs yes, I change my oil every year or 6k. Mine actually only does 3k-4k before I change the oil. I would never leave it till 12k. I don't think its cost effective.

Hi Thirteeneast, thanks for the comments, how many miles has your 996 done? Mine has 118K on the clock. I do about 12K a year so I could change oil twice a year at 6K. When you say cost effective are you refering to engine blow up then?? Would have thought modern synthetic oil would still be doing a good job at 12K, some modern service intervals go up to 18K?? I guess if you are only doing 3K a year then oil would require changing due to lack of use, if you see what I mean. Bst Andy

I don't think fully synthetic oils do a good job for consumers at all, If they did cylinder scoring on cars under 100k would not be such a common fault. In fact my heads a mess with Fully synthetic oil I change my oil regular mainly because its the same cost as a tank of gas and could save me a bill of £££££. It doesn't take long and is the single most important part of your car I don't let any of my cars do more than 6k before an oil change. Not even the banger I use for work it just makes no sense. If theres anything wrong your going to pick up on it 6k earlier. Just my choice of course but a small price to pay in grand scheme of running a Porsche. (or any car) Mine has 54k on the clock and gets used every weekend problem is the millage/use is split across three cars so therefore is less on all.

Possible that synthetic oils dont go a good job, I guess if you only used mineral oil scoring might appear earlier, or possibly later? We run a fleet of old mercs and use semi synthetic..we have a 300D with 470K miles on it...agree small price to pay guess its a bit load dependent so 6K change makes sense...nice problem to have three cars! Bst Andy

I wouldn't worry about bore scoring on a 3.4. It is pretty much unheard of. I would say use an approved 5W-40 synthetic, and change it every 6000 miles, and you won't go far wrong.