cold engine knock, diagnosis, lifespan and further damage prevention.

I get a knock noise on the gen1 2.7L Cayman when engine is cold and its idling. Noise is barely audible if you put your ear next to the driver's side wheel. Knocks with a cold engine, fades away into not audible as the engine fully warms up. Louder on drivers side but can be heard from passenger side if you listen carefully next to the wheel. I think I can hear it knock/slap when I rev it slightly but I'm not sure since there is much noise from the engine and exhaust. Suspecting a piston slap. Will check the oil and filter for metal...but the question is: if its a piston slap..and it probably is...what is the lifespan of these engines with such a problem? And is there anything that can be done to stop the further deterioration of the cylinder/piston ? Suggestions, opinions?

You might want to check the coolant pump. Sent from my XT1650 using Tapatalk

hm, you say the bearing play can knock like a rod or piston? I'll get my stethoscope Coolant temp climbs normally and stays at 80deg C no matter what, so pump is still functional.

The most common ticking is from tappet/hydrualic lifters in startup until oil pressure is high enough to get them fully pumped up. Second is from the timing chains after that other issues coming from wear related parts. The bottom end of these motors is very robust if maintance has been carried out in a timely manor, not 10,000k oil changes. I change mine every 4000 miles in my garage. Get my hands dirty, but look at all the suspension pieces, oil pan, examine my oil filter by cutting it apart. If you want to get ride of the ticking noise on startup, then use a more expensive motor oil to help coat the surface of the metal parts and change it often. "Engineering motor oil RAT/540" blog will give you some ideas how to solve your ticking noises. Who knows what has happened to your motor in the past? Maybe overheat from a failed water pump, maybe oil change at 15,000 miles, or sitting in a garage for a couple of years, then ran hard causing a small amount of bore scoring. Hows the exhaust on startup, white smoke, blue smoke? How much oil does it use? Read the blog, think about the application to your situation then ask more pointed questions.

This car is a demo/ launch car and it was a dealer showroom car used by the dealer(Munchen Germany) for its first 100k miles. After that, it was bought for a young girl who probably did not drive it hard, and she only covered around 15k kilometers. Should have been serviced properly and not driven in anger a lot...but like you said...you never know. I will do the oil change soon and i'll use what I used for my 924s, Motul 300V. I'm coming from the 924 ownership and I'm a bit surprised how sensitive these new engines are...but I do love them as well EDIT: what about running 5W40 oil? is that a good idea to use a bit thicker oil or not?

You probably hear the lifters until oil pressure builds up. Good quality oil should alleviate the issue. Pretty normal. Since I switched to Motul X-cess 8100 the initial knock all but disappeared.

If you do not live in a cold damp area, I certainly would run a little thicker oil, like 5w-40 or even 5w-50. Castrol 5w-50 was my oil and took away my chain noise completely until about 4000k miles then would wear out and chain noise would start again. I changed to Driven/Joe Gibbs DT-40 due to a LN package with deep sump/windage tray to prevent oil starvation on high G corners. Castrol 5w-50 has a small amount of ZDDP, which RAT/540 says is useless, but in my case the Castrol formula certainly seemed to work to silence my noisy cam chains. Driven DT-40 also has ZDDP, so in the future, I may have to replace my Cats. If you did a PPI before purchase, that would have detected bore scoring as there really is no cure after damage is done short of a complete lower end rebuild. Does your car smoke on startup? 2.7's are less prone to bore scoring than 3.4 motors due to more cylinder wall material, keeping the liners completely round during high temp issues (water pump, coolant leak, track work) or startup and not warming up the engine before heavy throttle.

I think I'm going for Motul x-cess 8100 5w-40. Its fairly warm around here and I drive a 4x4 suv in the winter and as a daily. I bought the car sort of blind, I just listened to the engine for bad noises which it does not have, especially when warm. Thanks for the replies guys. Trying to post some videos, let me know if you can see them or not. Here is the startup just now. The engine is kept higher revving and noisier for the first 25 seconds, then the idle RPM drops and you can clearly hear the knock. Sometimes its just a single regular knock but sometimes I can hear two knocks very close one after the other so I guess its the tappets either not filling up or being a bit stuck. https://www.youtube.com/watch?v=L4h-L6F59d8 It does not smoke at all at the initial start up, but after 30 seconds or so there is some smoke, it does not smell like burnt oil, its more like white smoke and I have read its fuel thats being burned to clean the cat? Ambient temp is 21deg Celsius. https://www.youtube.com/watch?v=5LqxxnTYh7U

That white smoke is water evaporation as the car warms up. It condenses on the inside of the exhaust when the car cools down after use, then, steams off as the car starts up the next day to disperse. Thats normal stuff will all engines. you surely kow that. The engine knock sounds like the clutch thrust bearing, normal stuff. I presume your manual transmission? Does it go quiet when you press the clutch? People over complicate issues. If your worried about the IMS don't on an 07 car. Change your oil regularly and forget it. Get in and drive the beast.

Its a 2007 tiptronic. I understand that I should not be so worried I took it to a Porsche service, they said that the cold engine noise can be the cam chains, perhaps the tensioners not raising all the way...worn oil...to thin oil. They found a misfire on two coils, they also said that those misfire can cause additional smoke and even engine knocking noises...so I will replace the coils and change from 0W to 5W engine oil. Will use my favorite oil, Motul..maybe i'll go for the 300V as I always did with my 924 turbos.

Driving the car more often has reduced the noise and the smoke output. I guess it needs to be driven. I will change to 5W40 oil soon so that should further improve the situation.

I have experienced the same type of noise on my '07 as well. After doing a 1,300 mile road trip in the car the noise went away. Guess it needed a good, long run to get everything cleaned out. Was never really worried about it given it went away with a little bit of throttle. The lifters in my 944 make the same kind of noise every now and then.