1st September, the Daily Telegraph published a buyer's guide for the 996 - oil gunk

See below email from an anxious member requesting advice What experience of this emulsion do you have? From: Steve McHale Sent: 19 September 2005 13:14 To: Nic Doczi Subject: RE: 996 C4s, Emulsion under oil filler cap [FONT=comic sans ms"] Nic [blockquote] T[FONT=comic sans ms"]his sound like a car that does a lot of short journeys 12,500 in two years! In engines like this the oil never reaches full operating temperature ( above 100 deg C ) for long enough to totally [FONT=comic sans ms"]evaporate the water vapour which is produced every time the engine is started from cold, this vapour will condense at the highest points as the engine cools down[FONT=comic sans ms"] causing a build up of emulsion in the filer neck Tell him to take it on a track day that should sort the problem. [FONT=comic sans ms"] [FONT=comic sans ms"] As usual with the press there is a little bit of truth in there somewhere. 3.4 engines crack cylinder heads this usually results in the cooling system filling up with engine oil but in some cases we have seen the core plugs in the heads fall out its very easy to spot either one fills the header tank full of engine oil the other dumps more than two gallon of coolant into the sump [FONT=comic sans ms"] [FONT=comic sans ms"] Steve Sent: 17 September 2005 18:30 Subject: 996 C4s, Emulsion under oil filler cap On Saturday 21st September, the Daily Telegraph published a buyer's guide for the 996 range including my car, a 996 C4s. The article said that if one was a used car buyer and thetre was an emulsion under the oil filler cap one should not buy the car as it probably needed a new engine! My car is just under two years old and still under warranty it has done 12,500 miles and has had the oil filler neck and cap cleaned out by the main dealer twice and once by me as this emulsion was present. The gunk has returned again and it seems that this is to be a permanent feature of the engine. The main dealer, Dick Lovett in Cardiff, says that there is no problem, that they all do that and that the engine is fine. I have written to Porsche GB Ltd and had a brush off. I have suggested to Porsche that they demand a retraction from the paper and they have declined to do that so far. Who does one believe? Does my car need a new engine? Is this a standard feature of this engine? How can the Daily Telegraph print this sort of information unchallenged? I have always understood that the oil and water should be separate - this seems to be a "no-brainer" They are mixing in my car and I am naturally very concerned. Have you any advice to help resolve my dilemma? [/blockquote]

If I used my old 944 for journeys to work (short runs) then I used to get a film of "mayonnaise" under the filler cap - scared the willies out of me until I was reassured the short journeys and the long filler neck combined to cause the moisture to emulsify in the filler neck in this way. A longer journey will get rid of the emulsion as stated.

Whilst looking for my current 996, I found one which I had checked by Peter Morgan, he commented on heavy water suds (mayonaisse) in the oil filler neck. He said that it wasn't conclusive evidence of a problem but suggested extreme caution. It could signify little use or that there is the mixing of oil and water. It was suggested by the dealer that the suds were there because it had been used for repeated small journeys and had been regularly left standing for periods of time due to the owners job. I ended up buying a different car from a respected specialist!

The problem is that it is a warning sign, so potential purchasers will go elsewhere. The owner may well know why it is there, but the purchaser can't really be expected to verify it. A track day sounds an ideal idea. (Can I volunteer to drive it hard for him? [ ])

The milky (white/yellow) substance around the oil filler cap is a characteristic on 996 engine range (both 3.4/3.6 engines), it alone is NOT a problem area whatsoever to cause concern, most cases are low infrequent mileage useage. However once our 996 Technical Support member returns from annual leave I will post the official reply from the Register, with a better full Porsche explanantion to the question. Regards Johnny McGirl 996 RS -Panamera a bit down the line....

The mayonaise like substance is a characteristic of ALL INTERNAL COMBUSTION ENGINES not just the 996 and not just water cooled engines!!! It is in almost all cases caused by condensation mixing with the oil, usually on the first bit to cool down, ie. the 'rocker cover' area and with the Porsche design of the 996 type this area is the the oil filler cap and pipe. It can be exacerbated by the temperature and humidity when and where you park etc and short journeys tend to be a prime example of the worst sort of conditions. The problem lies in it also is a symptom of coolant mixing with oil and that is a different scale of problem. Worst offenders are cars on dealers forecourts that are driven from storage about 15 feet then parked all day then driven 15 feet back again. When I was a poor student I can remember checking old £100 rust buckets and if suspicious, whipping off the rocker cover to see if there was more signs of water on the valvetrain. When engines had thin steel rocker covers the phenomena was very common.

To a greater or lesser extent, it is true that "mayo" can be found in certain areas of many car engines ( it is even to be found in the filler cap area of my Mother-in-Law's 1940 Lagonda Rapide, and that V12 cyl. cast iron block is virtually indestructible ), but I do know that even the slightest amounts of it appearing in one of Alfa Romeo's V6 engines of about 20 years ago was the cause of Alfa accepting almost crippling warranty claims for porous engine blocks, for which they eventually produced a modification kit as a prophylactic. SGLB