Major mayonnaise - help!

Am looking to buy a 2002 996 C4S at the moment. Car has a replacement engine 40k miles ago, rebuilt by Hartech. Has since had lots of lots spent on it and is a very well cared for car. It's at auction so I can't speak to the vendor. All looks great, but upon looking in the oil filler cap - check this out. I know some milky residue is common here - but how would you feel about this much? On the plus side, it's winter and the car is London based so potentially doing lots of short trips and never actually burning off the condensation in the engine. Coolant is fine, as is the oil on the dipstick. Thoughts? Is it within the spectrum of normal, or walk away?

Sounds like it needs a good clean out and a proper road trip to me..it will likely me as you said lots of short journeys. If unsure get it inspected but there are plenty of them to look at to buy one with a potential issue ? Or some fresh asparagus and a poached egg Could be the light or the picture….but I’d be more concerned about the paint mismatch on the front wing to door to rear quarter ? From experience it’s a nightmare getting silver to match without painting the whole side of the car.

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Thanks for your thoughts - I’m erring towards thinking it just needs a proper long blast. Re the paintwork - it’s had a full respray at a cost of £9k and in the flesh looks pretty good.

It looks very well I must say. Always worth double checking that passenger side again though. I’ve got paint OCD so tend to spot these things

Sorry to be the bearer of doom and gloom but that doesn’t look at all normal to me. My 996 did plenty of short London trips, and the underside of the oil cap never looked like that. I would at the very least be getting a professional inspection carried out. Having seen the auction listing I note that the total cost of the rebuild is quoted at c. £9k, which makes me think it probably didn’t have the full works from Hartech.

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Thanks! Here's the list of the work done to the engine - wouldn't be expecting this to blow a head gasket or anything. If you were being picky you could wonder if cylinders 1, 2 and 3 could have been re-lined but that's unlikely to contribute to any oil filler mayo?

If thats normal, I would hate to see failed one

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That's only 3 Nikasil liners, so not a "Full" rebuild. Been repaired on a budget IMHO

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Mine's been worse than that for the 8 years & 60k miles that I've owned it and it's not blown up yet. Serviced every year by Northway and they've not raised any concerns. I'd say it's pretty normal.

Just give Hartech a call - they will put you straight.

With any other car I would walk away, but apparently this build-up can be common in the 996 due to the length of the oil filler tube; especially as you say if the car has a usage pattern of standing around interspersed with short trips. My C4S (also with Hartech rebuild) had a similar amount of gunk when I bought it and I have cleaned it all out, changed the oil as a precaution, and it's been fine since. So it wouldn't necessarily put me off. I know it's an auction, but does the car come with a warranty so that if the gunk continues to appear you can claim something back?

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No warranty - sold as seen. I think it might make sense at a bargain price, but once you get into the middle of the estimate (plus fees), not so much.

Without knowing when the pipe and cap were last cleaned it's not possible to know how bad it is. Personally that wouldn't scare me, what would though is if I'd owned the car for a couple of weeks and it looked like that after it'd been thoroughly cleaned. Although it doesn't give you much confidence about the mental ability of the seller. Who in their right mind would be trying to sell a car without cleaning that out........it's like trying to sell a pair of soiled underpants on ebay and having them listed as 'New'.

If you take the dipstick out and that looks the same too, then do a runner.

Three new liners a decade ago... Six would have been nice but as long as 1-3 are still not significantly scored, all is well enough here. You can't ask for a scope check due to the auction though so listen to it running whilst warm and ideally get somebody who knows how scoring sounds to listen. As for the mayo, it is indeed true that the super long oil filler pipe doesn't always get hot enough to turn the mayo back into it's component oil and water, and thus evaporate the water. An auction is always going to be a gamble but nothing about this car screams dealbraker or walk away - it could be all right. It's down to price and your attitude to risk!