997.2 Engine Reliability
03-05-2015, 07:50 PM
#228
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Just as it can happen with the 997.2 DFI engine... except that with the 911, the left exhaust tail pipes mean cylinder bank #1 (and not bank 2 as in the Cayman) AND with the DFI (9A1) engine the problem is of a different nature as explained before
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03-06-2015, 07:18 PM
#229
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There's also the important feature of injecting more fuel to cool down the cylinder inner temperatures when the engine is operating in a high temperature environment (as opposed to low outside temperatures) which can equally lead to fuel intrusion on the cylinder walls. Again, cylinders from bank #1 will be the most affected. So, the addition of the third radiator we see on the MY11 997.2 PDK and GTS models onwards is of high value with the DFI system :
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03-08-2015, 10:02 AM
#230
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I had a very nice deal offer for an equally very nice MY09 997.2 PDK Carrera S but it seems that the early model years are precisely the ones to avoid! 
just had a look on the Porsche PET and there is a clear difference between replacement 2009 engines and 2010 engines (both 987.2 and 997.2)hence as I said once before are the random failures we have seen been early cars ie pre 2010 and was there somekind of upgrade 2010 model year onwards once Porsche became aware of a problem after a number of early 2.9 engines failed which seemed to affect 2009 model year cars
Gen2 997 - bore scoring
Gen2 997 - bore scoring
03-09-2015, 10:26 PM
#231
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03-09-2015, 11:49 PM
#232
Regardless, this argument against the 9A1 has been a bit like biting into a lemon and finding it is bitter and concluding that the tangerine must be the same.
I have not heard anyone with a 997.2 state that they have had reliability problems. There have been ample opportunities to do so.
It's tough to prove a negative, and it's tough to prove something without data. But in this case, the absence of feedback is speaking volumes to me. We are going on 6 years of this motor. If it has an Achilles Heel, it is hiding it well!!!
03-10-2015, 12:10 AM
#233
Rennlist Member
CaymanPower has been basing reliability on his/her 9A1 without DFI. I do not know of any 997.2 vehicles that are not DFI. Then again, I didn't realize that there were any 9A1 motors without DFI.
Regardless, this argument against the 9A1 has been a bit like biting into a lemon and finding it is bitter and concluding that the tangerine must be the same.
I have not heard anyone with a 997.2 state that they have had reliability problems. There have been ample opportunities to do so.
It's tough to prove a negative, and it's tough to prove something without data. But in this case, the absence of feedback is speaking volumes to me. We are going on 6 years of this motor. If it has an Achilles Heel, it is hiding it well!!!
Regardless, this argument against the 9A1 has been a bit like biting into a lemon and finding it is bitter and concluding that the tangerine must be the same.
I have not heard anyone with a 997.2 state that they have had reliability problems. There have been ample opportunities to do so.
It's tough to prove a negative, and it's tough to prove something without data. But in this case, the absence of feedback is speaking volumes to me. We are going on 6 years of this motor. If it has an Achilles Heel, it is hiding it well!!!
+1, amen! I think it's time to move on and let it go.........
03-11-2015, 11:31 AM
#234
I guess what I’m not getting is why there is so much talk about the problems with the DFI engine. From what I know Porsche used an intermediate shaft to slow down the camshaft for 40 years. When the intermediate shaft needed a self-lubricated bearing instead of an oil pressure fed bearing in the water cooled version (M96/97) there were problems. If there was going to be an issue in the DFI I figured it might have been from the new design having the camshaft now rotating at the same speed as the crankshaft, but with seven years in operation it appears not to be problematic. All engines have a weak link and will fail but I really don’t see anything unusually troublesome with the DFI’s that will result in them failing to deliver a normal expected service life. I don’t proclaim to be an expert in Porsche engines so I’d welcome any corrects.
03-11-2015, 02:01 PM
#235
There is actually very, very little talk of problems. This thread is kept alive by a vocal minority (and now I'm dragging it along further too) but the engine appears very strong.
03-15-2015, 11:20 PM
#237
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You see, since the PDK is cooled down via the engine coolant Porsche has realized then that maybe it would be better to add an extra cooling effect from a third centrally mounted radiator in order to make sure that when PDK gets hot enough the engine doesn't run out of the necessary cool coolant, namely the more powerful 3.8 S version with its enlarged and therefore much closer engine bores for the same overall engine dimensions - which equals to less heat dissipation!
Last edited by CaymanPower; 03-15-2015 at 11:52 PM.
03-16-2015, 02:09 AM
#238
Nordschleife Master
If they were the same then why only from MY11 onwards does the PDK Carrera S come standard with a third central radiator?!
You see, since the PDK is cooled down via the engine coolant Porsche has realized then that maybe it would be better to add an extra cooling effect from a third centrally mounted radiator in order to make sure that when PDK gets hot enough the engine doesn't run out of the necessary cool coolant, namely the more powerful 3.8 S version with its enlarged and therefore much closer engine bores for the same overall engine dimensions - which equals to less heat dissipation!
You see, since the PDK is cooled down via the engine coolant Porsche has realized then that maybe it would be better to add an extra cooling effect from a third centrally mounted radiator in order to make sure that when PDK gets hot enough the engine doesn't run out of the necessary cool coolant, namely the more powerful 3.8 S version with its enlarged and therefore much closer engine bores for the same overall engine dimensions - which equals to less heat dissipation!
03-16-2015, 08:13 AM
#239
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Before you make this kind of statements and become a source of misinformation (I wouldn't classify you as a troll though) you should first ask yourself the following... 'wait a minute, why does only the PDK S version gets a third centrally mounted radiator from MY11 onwards and the equivalent MANUAL S version does not'?!
There's a reason for this... there's always a reason as long as you are willing to use some sensible and HONEST reasoning!
And, the reason is simple... the PDK oil cooler radiator/ heat exchanger that you've mentioned does provide cooling for the far more temperature critical clutch fluid and hydraulic oil, rather than to the gear-wheel oil. It just happens that you've missed a very important little detail: albeit fitted on the outside of the transmission case the oil cooler is an OIL/WATER heat exchanger, which means that there's an engine coolant supply line and an engine coolant return line that runs to and from that oil cooler.
The air cooled era is over... you should have known by now!
Last edited by CaymanPower; 03-16-2015 at 11:02 AM.
03-16-2015, 09:11 PM
#240
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I think the third radiator was offered in 2011 and 12. After that, I think they went back to two radiators.