Hi,

I noticed lately that upon cold start my engine sounds almost like a Diesel engine. Doesn't sound like it used to. I changed the gas to fresh gas and it is still the same. Anyone experience this?
Any ideas what it might be? Seems to go away after time.

Thanks,
Jon

 

That's not a lot of info to go on, but first guess: Look up stuck lifter or collapsed lifter. It can happen infrequently but not be every time you start your car.

Edit, when was your last oil change?

 

Last oil change was 7k miles. Will be scheduling an oil change very soon.

 

7k miles... Where is it now? 14k 30k 50k, not enough info on that answer buddy.

 

48k miles now

 

Changed 7k miles ago,...or changed when the car had 7k miles?

 

Changed 7k miles ago. Car has 48k mikes now so changed at 41k.

 

2011 4S,...DFI engine...in for an oil change at an Indy Porsche shop,...owner said when he heard it start up he thought something was wrong...loud... Another mechanic said that's how the new DFI engines sound....first one he had heard.

 

Mine is an 07 4S

 

I do know how diesels sound, but is your car sputtering? Is it grinding? Hesitating? Sounding as if running on 5 or 4 cylinders.

All I could tell is that your issue occcurs in the morning. Long dark shot recommendation: put some Techron (twice if possible) and start from there.

 

Depending on your driving habits 7k is getting towards the longer end of oil changes. If you do lots of short drives, the engine does not heat up fully and you can get moisture from combustion diluting the oil. Also if you do lots of hard driving or track days you'll want to change it sooner.

It's difficult to diagnose a car from the internet with such a vague description. Did you check the threads on collapsed lifters? Did any of those threads describe your issue? Also, do you let your car sit for long times between drives?

Barring any genius internet arm chair mechanic help, I'd take the car to a competent indy for the oil change and hopefully you can also leave the car there overnight show them the noise on cold start.

Edit, one other thing... could be something in the exhaust that is loose and when it heats up expands and stops rattling.

Here's a thread from the other forum: http://forums.rennlist.com/rennforum...-thus-far.html

and another one with video: http://forums.rennlist.com/rennforum...his-sound.html

 

It's not really a rattling or ticking noise. The best I can describe it is it sounds like a typical Diesel engine which has a very distinctive sound.

 

So your hearing a knocking noise?Does the knock speed up with engine rpms?Is it only when cold or after it heats up also?Elaborate?

 

No not a knocking sound either. It's like a deep grinding noise like a Diesel engine or maybe a truck sounding engine. It's more the tone of the engine rather than a knocking, ticking or rattling sounds. It speeds up with rpm and actually doesn't go away when it heats up. It sounds like I have a Diesel engine now, not gasoline.

 

I would call AAA and have them take my ride to my local Porsche shop,...if you have AAA. Have a pro look at it.