996 C4S Engine noise

Sell the M3 and fix it, they are worth it and the M3 will be surplus!

This is why people need to have a bore scope on a 3.6 before buying, and even then be aware that it will probably happen at some point, and seemingly can happen overnight.

Interesting the noise just started like that rather than coming on gradually, as far as I know the cylinders get hot due to poor cooling, the piston coating flakes off - gets trapped in the rings and scores the bores. So once a bit flakes off it must pretty quickly trash the bores.

I have had other cars with worn bores and piston slap, but that has gradually come on and got worse slowly - presumably because that wear was a more natural wear not chunks of piston coating being dragged down the bores.

GMG said:

...a sobering story for anyone thinking of buying one of these cars and reinforces my oft stated view that to mitigate risk one should buy a rebuilt one or accept that you need £10k plus available should,as in this case, the worst happen...

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+1

g911omr said:

I'm sorry to hear the bad news. What makes it worse is that the previous owner new very well that the car had an issue. I would absolutely make contact and give him the opportunity to comment on the situation. Bad form and actually rather stupid depending on the type of person who ends up getting turned over.

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TOTALLY agree with you.......previous owner knew 100% :gunfire:

How *%@$s like that can sleep at night is beyond me. Let's hope there is some Karma around the corner for him :judge:

OP......I have been there.

On the plus side, I can highly recommend Hartech. Grant and Tobias are great lads :thumb:

Also you will be getting a spot on engine after it is done. The rebuild I had done was 6 years ago.
I sold the car a year after the rebuild and was in contact with the guy I sold it to and he said it has run absolutely fine for the last 5 years.

By the way...just because it is tapping (yours is a little bit noisier than mine was) and probably using a bit of oil doesn't mean it's about to explode....I ran mine for nearly a year until the water pump gave up before I had the rebuild done.

I had a warranty, so I only forked out about 40% of the cost....it only covered a large percentage of the cost of the new parts and none of the "Betterment".

Interesting one on the previous owner... I have two Porsche-owning friends (with a 997C2S and a 996 C4S respectively) and I can guarantee neither have any idea whatsoever about bore-score, IMSB etc. They just are not those sort of people. Chances are they could sell those cars utterly unwittingly with a major fault that had not manifested in a serious noise or clouds of smoke which might prompt a visit to a specialist. Certainly a sooty exhaust or higher oil consumption would not worry them.

There is no guarantee that the previous owner of this car knew as there were clearly no symptoms that revealed themselves to the buyer in his own pre-purchase checks.

Robertb said:

Interesting one on the previous owner... I have two Porsche-owning friends (with a 997C2S and a 996 C4S respectively) and I can guarantee neither have any idea whatsoever about bore-score, IMSB etc. They just are not those sort of people. Chances are they could sell those cars utterly unwittingly with a major fault that had not manifested in a serious noise or clouds of smoke which might prompt a visit to a specialist. Certainly a sooty exhaust or higher oil consumption would not worry them.

There is no guarantee that the previous owner of this car knew as there were clearly no symptoms that revealed themselves to the buyer in his own pre-purchase checks.

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..yes but the OP had said that the owner had just put the car in the garage and that they had given it a clean bill of health.

Just listen to the tapping in the video and I would suggest that no Porsche specialist would miss that and together with the sooty tailpipe.......even I would be able to diagnose that :thumb:

Rhodris-dad said:

Robertb said:

Interesting one on the previous owner... I have two Porsche-owning friends (with a 997C2S and a 996 C4S respectively) and I can guarantee neither have any idea whatsoever about bore-score, IMSB etc. They just are not those sort of people. Chances are they could sell those cars utterly unwittingly with a major fault that had not manifested in a serious noise or clouds of smoke which might prompt a visit to a specialist. Certainly a sooty exhaust or higher oil consumption would not worry them.

There is no guarantee that the previous owner of this car knew as there were clearly no symptoms that revealed themselves to the buyer in his own pre-purchase checks.

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..yes but the OP had said that the owner had just put the car in the garage and that they had given it a clean bill of health.

Just listen to the tapping in the video and I would suggest that no Porsche specialist would miss that and together with the sooty tailpipe.......even I would be able to diagnose that :thumb:

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Umm, the car started tapping only after the new owner got it out of the garage after 6 weeks and 500 miles driving. He'd not noticed any sooting or tapping prior to purchase, else presumably he'd have queried it as he says he'd done his homework.

If the indy was not asked to do a borescope check then I can't see how they'd know what state the bores were in to give it a clean bill of health, other than superficially.

So unless the previous owner put some secret sauce in the engine to shut it up I'd be inclined to put it down to bad luck (or good luck on the part of the seller!)

Robertb said:

Rhodris-dad said:

Robertb said:

Interesting one on the previous owner... I have two Porsche-owning friends (with a 997C2S and a 996 C4S respectively) and I can guarantee neither have any idea whatsoever about bore-score, IMSB etc. They just are not those sort of people. Chances are they could sell those cars utterly unwittingly with a major fault that had not manifested in a serious noise or clouds of smoke which might prompt a visit to a specialist. Certainly a sooty exhaust or higher oil consumption would not worry them.

There is no guarantee that the previous owner of this car knew as there were clearly no symptoms that revealed themselves to the buyer in his own pre-purchase checks.

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..yes but the OP had said that the owner had just put the car in the garage and that they had given it a clean bill of health.

Just listen to the tapping in the video and I would suggest that no Porsche specialist would miss that and together with the sooty tailpipe.......even I would be able to diagnose that :thumb:

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Umm, the car started tapping only after the new owner got it out of the garage after 6 weeks and 500 miles driving. He'd not noticed any sooting or tapping prior to purchase, else presumably he'd have queried it as he says he'd done his homework.

If the indy was not asked to do a borescope check then I can't see how they'd know what state the bores were in to give it a clean bill of health, other than superficially.

So unless the previous owner put some secret sauce in the engine to shut it up I'd be inclined to put it down to bad luck (or good luck on the part of the seller!)

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Just like your friends........I did not notice sooty tailpipe or a tapping before I took my car to Hartech for a service. (circa 2010 scoring had not been well publicised)

996, 997.2 and the 991.1 I have now are not the quietest engines at tick over and unless you have heard the ticking of piston slap before, I suggest you would not know. Compared to a Jag V12 or a Roller, they sound deisel like :floor:
In my case, Hartech knew before the scoping that it was scored.....they just did it to confirm and provide me with photographic evidence.

The OP has made the video to ask what the tapping noise is...so he certainly would not have recognised it in the first instant.

I also suggest that listening to the video that the tapping is quite loud and to get to that state, would have been ongoing for quite some time.

From my own experience, I drove 7.5K in the first year of ownership and the tapping had not drastically worsened.

It is really unfortunate for the OP as, through no fault of his own, he has not got enough experience to have been able to diagnose the issue on inspection...the way in which I was caught out too! How many have in the early days?

Your suggestion that the previous owner and specialist were not aware of this issue is possible but to me is very unlikely. Specialists by name know these cars and would be checking for signs as a matter of course. One thing they won't tell the owner is that he was not allowed to "sell it on".

When I took out the warranty, it was inspected by an engineer and he mentioned the tapping but said he didn't think it was anything to worry about and passed it. I admit I was very fortunate (not fortunate to get the scoring :floor: ) and it did save me some money.

But that goes to show what an innocuous sound it can be to the untrained ear and that engineer was clearly unaware of the issues these cars suffered.
(I am sure they are now).

Mine was diagnosed at around 80k miles too and I think the consensus is that once the cars have passed that mark the occurrence of scoring diminishes.

As lots of owners have pointed out, it is only a relatively small percentage that have the issue.

But that doesn't help the unfortunate OP....but at least he has a sort after model that in the future will only increase in value.......and with a Hartech rebuild will be very desirable :thumb:

I've rambled on a bit...apologies

Makes sense... I envy new owners the joy of using their cars without the paranoia of "wazzat noise??" that seasoned M96/7ers have!

I got the impression though from the OP's first post that the noise literally suddenly started one morning, to the point he video'd it to ask the question. Which is surprising for bore-score, I always imagined that unless there was some reason (e.g over-revving when cold, overheating, low oil etc) it would get gradually more symptomatic until it sounded like a cement mixer.

Bad luck OP :nooo:

Fantastic attitude though dude :thumb:

Lots of conjecture on here about the PO who nobody but the OP knows anything about. In my experience the vast majority of owners of 911's have no idea about their failings or any mechanical nouse at all. You'll never know if they knew about it but its a fair bet they didn't.

As others have said, there's no rush in getting it fixed - you can run them for ages before its necessary. By the tone of your post I suspect Hartech have given you all the info you need about running it.

The 996 4S is a fabulous car. Glad yours has such a good owner :thumb:

I know what you're saying Robert and Raggy, the noise came on afterwards etc and some owners are just not that clued up or interested, but one thing he would have noticed was the oil usage.
Unless he never checked it, let it run low, his Indy checked and said get rid, in which case he still knew.
I'd definitely be getting in touch and seeing what he has to say.

ragpicker said:

Fantastic attitude though dude :thumb:

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I can't say I agree, I think if I'd been stitched up by £10k+ by the previous owner (the chances he didn't know it was ****ed are pretty slim) I wouldn't just say 'hay ho', I'd be at least contacting the guy and looking for some compensation.

If I put the shoe on the other foot, and I sold my car to someone and it failed catastrophically within a few hundred miles then I would want to be helping out in some way, I wouldn't feel right just letting the new owner deal with such a nightmare situation.

Like I say, the chances that the previous owner had absolutely no idea that there was anything wrong with the car are pretty slim.

Marky911 said:

I'd definitely be getting in touch and seeing what he has to say.

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Probably "jog on mate" and "caveat emptor" and then block his number.

Theres a thousand threads on pistonheads inverse to this where people selling cars are guilt tripped by nasty buyers into part refunds.

Its all part of the risk of buying anything second hand privately.

Marky911 said:

I know what you're saying Robert and Raggy, the noise came on afterwards etc and some owners are just not that clued up or interested, but one thing he would have noticed was the oil usage.
Unless he never checked it, let it run low, his Indy checked and said get rid, in which case he still knew.
I'd definitely be getting in touch and seeing what he has to say.

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Knowingly selling on a car with problems would make the seller liable in court...dealer or private.

However, in the real world, proving a private seller has knowing sold the car with problems would be nigh on impossible.

At least the new owner hasn't taken the option to"sell on".......which shows there are still some honest, decent people left in this country. :judge:

I admit I am cynical....but we are all a product of our environment.

E.G last year I had some toerag send me a solicitor's letter saying I had reneged on a 2 year contract for 28 mobile phones....and I owed him £45.000 :floor:

Just an update, I've got my Porsche back from the mechanic, he's probably well know on these forums, based in vauxhall. S.London.

I had the minor service and brake fluid change, couple of other things. His opinion was they see quite a few 911's with this issue and they keep them running by carrying out oil changes every 6 month, (which I can do myself), and they have several still on the road after a few years.
He thought mine was not so bad in the schema of things.

I've done research on rebuilds, the consensus is and I've rang around a few places. this issue can be sorted for around £6-7k. Hartech's everything and the kitchen sink solution is £12k inc VAT.

The difference with Hartech is they do a cylinder lining unique to them because of the investment they have made in their own tooling, but there are another 50 Porsche specialists in the UK who are very competent at more competitive prices. It just depends how far you want to go with a rebuild and what actually needs doing as opposed to all the future proofing of components you may do when the engine is out. You could probably sort out this issue for a base price of £8k even with Hartech, its when you start adding the extras the bill goes up.

I'm going to keep mine running for the next 2 years (I'm probably going to clock up 3k miles in that time), if it has issues I'll tackle them and like I said in about 2 years time, I'll schedule an engine rebuild with a budget of £7k.

If you think about it an engine rebuild warranty will be 2 years. If I keep the car running and it doesn't blow up in the meantime, which from all the specialists I've spoke to is a highly unlikely outcome, then over the course of 4 years, I would have spent £7k on the car (outside of servicing), which is about £1,750 per year. A bit higher than I expected but I'll have a rebuilt engine and probably a car good for another 10 years and then that investment is spread over even a longer term.

With regards to the previous owner, he may or may not have known there was an issue, but he didn't seem the type and to be honest I'm not going to pursue him, I've enquired once and he said talk to his mechanic, his mechanic, who is a respected specialist told me the car was 100% when it left him in February 2019. Thats closed for me, its my car, I've taken it on, I'll deal with it.

I picked the car up yesterday and drove it through an absolute downpour virtual monsoon and I was surprised at how insulated from it all I was in the Porsche, there were police cars, sirens blaring, rush hour traffic, roads flooding and sitting in the 911 in queueing traffic with the radio on it was just so serene and peaceful, LOVE THIS CAR!

I did notice however, that the rear windscreen wiper wasn't working, any tips?

I think what you are saying is the perfect approach to this issue, just drive it and save as you go until you feel the need to rebuild and out the other side you should have the perfect 996.