Well, the Forester is back at the dealer overnight, so they can start it cold and hear the piston slap or whatever the noise is. Naturally after 2 months of daily noise, it didn't do it this morning, but maybe the dealer will be lucky. I had quite a go-round with Subaru about authorizing a loaner car for me. To make sure they hear the noise, I videotaped a cold start and provided them with the tape. Funny thing is the Service manager's conversations with Subaru resulted in a regional Subaru rep. requesting permission to hear the car start as well. So, we will see!! chas
WELL GANG! THEY HEARD IT!!! I spoke to the service writer and he told me the Subaru regional rep actually heard the car make a cold start racket, and they are putting in a new timing belt tensioner tomorrow. Lets see if it works. Chas
I've been reading a lot of stuff off the Subaru technical website and came across the following, out of the Subaru Service / Technical Support Line Newsletter TechTIPS JAN/FEB 2003
-- begin quote :
SUBJECT: ENGINE NOISE WHEN COLD
(Note: This is a re-release of past articles.)
We wanted to review some of the past information on engine noise.
The 2000MY and current models, with the 2.2 and 2.5 engines were made more fuel efficient, more powerful, and had a flatter, more usable torque curve than in previous years. To achieve these objectives, it was necessary to make improvements and modifications to the Subaru engine lineup. The following are some of those improvements:
Short skirt, Molybdenum coated pistons (reduces friction)
Increased compression ratio (improved power output)
Improved cylinder head design (improved cooling)
Improved induction system (improved breathing)
As a result of these enhancements, some engines may exhibit some engine noise during the warm-up period after a cold start-up. This noise is a consequence of the engine improvements and is not, in any way, an indication of any engine problem.
A light engine knock, after cold start, that gradually dissipates as the engine warms up and is virtually undetectable (from inside the vehicle) once the engine has reached operating temperature, is a normal characteristic of these engines. Repair attempts to reduce this type noise are generally unsuccessful.
If you have a vehicle in which an engine noise is other than that as described above, be sure to take the time to check all possible causes prior to condemning the internal components of the engine.
Before replacing parts in an attempt to eliminate engine noise, the engine should be inspected externally and internally for another source of noise. A look at the engine oil is a good place to start. New engines will have a small amount of metal particles in them, but after that should be relatively free of metal.
Another area to look at would be the timing belt tensioner and the belt and sprockets. There have been cases where noises coming from under the belt covers and from external components sound like a deep internal knock.
If a customer complains of a cold engine knock, and the cause is from the improvements listed above, please reassure him/her that no permanent engine damage will occur. If the noise persists and is still clearly audible when the engine is warm, please consult your DSOM.
I went through a similar episode with my '02 Outback Wagon. Round and round with the dealer. We ended up leaving the car there overnight so they could hear the noise.
They kept the car for two weeks. The final diagnosis was :
bad timing chain tensioner. Turns out the tensioner is hydraulic. The original had air in it. When the engine was cold the timing chain slapped making a ridiculously loud noise. Sounded to me like dreaded piston slap.
Well, when the engine would warm up the air in the timing chain tensioner would expand, the timing chain would get tighter, then the slapping sound would go away.
After they returned the car to us (18k miles ago) I haven't heard the noise once.
Maybe you should ask them to investigate that possibility.
Paul, thanks so much for pointing this out. It reassures me that my dealer isn't making crap up. I hear this slight knock on startup too...and am hereby assured it's normal.
Makes me think that they may have replaced 2 timing belt tensioners on this car unnecessarily though.
-- Todd H.
2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Well Roy, seems like they heard it, cause it's sitting at the dealer waiting for the new tensioner. My noise was not a 'light knock' as described in the factory info. I hope I have similar results. Chas
Wow! I thinks that's called "spin". In engineering design, when you put too much emphasis on improving one parameter and in so doing have compromised another parameter to the point that it becomes a problem (and in the automotive business, a perceived problem is a problem no matter how hard marketing tries to convince the public it is not a problem), it's time to back off on the parameter that has been over-emphasised and bring the overall design back in balance. The proof will come when future designs will not be plagued by the problems that they've created in the existing design.
Hasn't someone posted in the past that Subaru has fixed piston slap by replacing the pistons with ones of an alternate design (i.e., longer skirts maybe)?
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
Wow lucky you . Ihave been fighting with my dealer for the past 2 years about my cold engine noise . Mine was diagnosis with piston slap . Subaru gave me a TSB from them saying that some engine noise is normal and as long as the noise goes away when the engine is warm,and they will do nothing about it . I also have the time belt noise but the last 2 times I left my car overnight it didn't make the noise . I did a lot of complaning about the piston slap noise . So the DSR from Subaru said he could probable get Subaru to autherize a short block but it may not help .Which I didn't have done . While he was there we went out and started 5 different subaru's and 3 of them had the knockning noise, and one of them was the H6 engine . He offered me a 100k 7year Subaru gold warranty plan free . So I have atleast some peice of mind for now . I am going to do a oil analysis at my next o/f change to see if there is any metal in the oil . I do have to say that the car burns no oil between changes . I have a 02 outback base wagon 4eat with 31k miles on it . My only problem with the car is the piston slap noise .
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