Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Knock Knock
#1

Maybe I should rephrase my previous post...

At cold start up my engine is perfectly quiet. After 2 to 3 minutes of warm up at idle a knock begins at the top of the engine in the variocam/center two cylinder vicinity. Sounds kind of like a valve ping under load and is irratic. I tried 96 octane with no improvement. It's hard to tell if the knocking is there as the engine is accelerated.

If it were the variocam gears/chain going bad I would think the noise would be worse at cold start up and would improve with oil flow? Maybe not? Maybe it's just a 98K engine showing its age? I do have an error code 1235 variocam present but do not know when this registered. Any ideas are appreciated. Thanks.
Partial Post: Please Login or Register to read the full post.
Reply
#2

Put a skrewdriver to your ear a listen around the cam cover.
This may help to pin point the area the noise is coming from.

I would order a new cam cover gasket set then pull your cover and inspect the cam gears.
Also check the j-tube for cracks.


Torque spec for the bolts is 7 ft./lbs.
Do not over tighten them, the snap easy and are like $12 bucks each.
Partial Post: Please Login or Register to read the full post.
Reply
#3

Is it a light knock? Perhaps it's a lazy lifter that has bled down[?]. I have a lifter or 2 that make noise once in awhile, but after I drive a bit they quiet down.
What viscosity oil do you use?
Partial Post: Please Login or Register to read the full post.
Reply
#4

I'd suggest pulling the cam cover off and inspecting the variocam unit, the tensioner pads(the top one is easily viewed, the lower one is a tad more difficult) and also pay close attention to the chain and sprockets on the camshafts...

If these appear Ok, then try a thicker oil, such as a semi synthetic 10W - 40 or 15W -50. If this retards or stops the noise then it could well be the lifters.

Using modern 'thin' synthetics on these engines can cause premature wear as they drain away quickly.....in particular from the lifters and head.....
Partial Post: Please Login or Register to read the full post.
Reply
#5

<!--quoteo(post=75207:date=Jul 9 2009, 05:51 AM:name=wasserkuhl)-->QUOTE (wasserkuhl @ Jul 9 2009, 05:51 AM) <{POST_SNAPBACK}><!--quotec-->I'd suggest pulling the cam cover off and inspecting the variocam unit, the tensioner pads(the top one is easily viewed, the lower one is a tad more difficult) and also pay close attention to the chain and sprockets on the camshafts...

If these appear Ok, then try a thicker oil, such as a semi synthetic 10W - 40 or 15W -50. If this retards or stops the noise then it could well be the lifters.

Using modern 'thin' synthetics on these engines can cause premature wear as they drain away quickly.....in particular from the lifters and head.....<!--QuoteEnd--><!--QuoteEEnd-->

Thanks for the advice everyone. Listening closer does suggest its not the variocam and just some noisy valves. I do run 15-50 semi synthetic. Might try a quart or two of Lucas engine treatment and see it that quiets things -- it did on my very noisy ' 86 audi 5000 engine.

I tried all the advice on clearing the error code with no success -- disconnect battery, 11 seconds on throttle -- is there anything else or do I need the Bosch tool?
Partial Post: Please Login or Register to read the full post.
Reply
#6

A Bosch tool is not necessary, however it makes things alot easier!

This noise could also be injectors, they can get very noisy as well. A decent porsche specialist will be able to remove these and get them ultrasonically cleaned for very little money(should!). Fuel treatments will do not much at all.

This lucas stuff, whats in it? I'd be weary of putting it in the engine.
Partial Post: Please Login or Register to read the full post.
Reply
#7

I wouldn't settle on the idea that it's simply valve chatter especially since you threw a variocam error. With your mileage, others have had similar noises to find out they were missing teeth on their cams. It's time for an inspection, not lucas additives.
Partial Post: Please Login or Register to read the full post.
Reply
#8

sounds like a loose cam chain hitting something.....
Partial Post: Please Login or Register to read the full post.
Reply
#9

<!--quoteo-->QUOTE <!--quotec-->especially since you threw a variocam error<!--QuoteEnd--><!--QuoteEEnd-->
As mentioned in the first post, there's no indication of when the trouble code was set, which is why he's trying to clear the code and see if it resets.
All the possibilities listed above sound a bit different, so perhaps a trained ear is needed...
Partial Post: Please Login or Register to read the full post.
Reply
#10

I'm having a similar noise problem in the same area. Mine is unpredictable...sometimes it's there when I start her up...like a lifter noise, and a bit of a squeak. Loud clattering when I stop at a light sometimes. Sometimes it goes away. It's very erratic. I have plenty of oil pressure, otherwise I would suspect lifters. Does it sound like a vario cam problem?

I don't mean to steal this thread, it seems like the same problem with both cars maybe. Mine has only 60,000 miles.
Partial Post: Please Login or Register to read the full post.
Reply
#11

I had a ticking noise just after I had the head gasket replaced. I was told it was a "lazy" lifter, to take it easy for about 10-15 minutes and it would stop. It did. I use Mobil 0W-40.

The Porsche DME Diagnostics/Troubleshooting manual, upon which the "blink"codes are based, says that disconnecting the battery or the DME control unit plug will clear the codes (page 5). Worked on mine.
Partial Post: Please Login or Register to read the full post.
Reply


Possibly Related Threads…
Thread / Author Replies Views Last Post
Last Post by flash
12-08-2008, 12:28 PM

Forum Jump:


Users browsing this thread: 1 Guest(s)