M96 intermitent thicking noise

Hi everyone, Im a bit worried about my m96 engine. Once in a while (heard it two times in 3 months) I can hear a thicking noise on cold start-up after the car sit for a couple days without being driven. Not too sure if its sound like a scored cylinded (Im actually in the deny phase), valve guide, injector problem, water pump issue or something else but it goes away when the engine gets in operating temp. and didnt came back for a couple months! It only happen when the car have sit for a couple days and went away after some spirited driving. No unsual smoke other than the 30 sec white puff on start-up with the SAI pump on which happen here and there during summer. AOS is new + lines, new IMS bearing, doesnt seems to burn oil as the level stay in the middle but I remember last oil change from an Indy, they topped-off at the highest mark and the engine burnt some oil on the return highway run after that it stays at the middle mark for the whole season. I didnt have time to do a bore scope or even take off the driving belt to isolate the noise but Im just wondering if by ear/experience you guys could atleast tell me its not a scored cylinder! Here's the link to the 2 videos taken 3 months appart: You Tube You Tube Thanks for your help Hugo

Chances are you got a sticky valve after sitting. Bore scoring ticking doesn't go away for months.

Those two clips sound different. Almost like the ticking in the 2nd clip is twice as fast as in the first clip. Neither sounds like knocking to me. How long till it goes away after startup? Maybe just the oil taking a few seconds to completely circulate throughout the engine.

The second clip sounds like a cold start. I agree the ticking sounds more like ticking then knocking. My bets are on lifters for this one.

I would also recommend getting the cylinders evaluated with a borescope. Not trying to be domes days scarring here, but Raby states that the ticking associated with bore scoring is commonly misdiagnosed as lifter noise. Search "Porsche 996 Bore Scoring" in YouTube. Good luck!

Mine does that sometimes as well when not driven for a while. Less so since I switched to Motul Xcess oil. What oil are you running?

Thanks for posting. I have the same issue. It goes away after about 15 seconds. I am having it fully checked in a few weeks. I am thinking lifters but somehow it always comes back to bore scoring and bearing failure. it reminds me of back when I was in HS and on the debate team. One of my schools teams, no matter the argument the team always ended up concluding it would lead to NUCLEAR WAR. It was kind of funny how a policy debate on asbestos would lead to NUCLEAR WAR...lol. i feel like that on these threads...all issues lead to a blown engine.

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Like how every single symptom query in webmd is possibly cancer.

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Perfect thanks guys I will defenately have the cylinder wall checked from the crank case. Im also thinking about doing it myself...I will evaluate the cost and think about it. I have to buy a bore scope..... Rockhouse66 I also use Motul Xcess 5w40, oil pressure is around 4.5bar during cold start and drop at 1.5 bar on idle when the engine is at operating temperature if my old oil pressure sending unit is right.... Ahsai is there something I can do to prevent this or that can help? For example the car is in storage for winter and Im affraid of the first start-up next spring. Should I add oil additive or something similar to help the start-up? Im basicly sure lifters problems cant really hurt the engine but I want to fix it. Should I try a different oil vicosity, blend? So here my plan please correct me if Im wrong: -Drop the oil pan, inspect/clean oil pick-up tube and do a bore scope. -Maybe try to change the oil for something else? Using Motul Excess 5w40 for now (Will have to learn more about it) I read you need to do an oil flush is switching from Motul oil to something else? -If the ticking continue I will take off the serpentine belt. So basicly if it make the noise, I shut off the engine without getting it warn, remove the belt restart and see what happen. -change the oil pump just in case -Change the lifters and lifters carriers You guys are right: one video is a "real" cold-start with SAI pump on cold engine idle-up , the second one, with SAI pump off , idle down I dont really know when the noise dissapear as I cant hear it from inside the car. But I guess it stops when the engine reach operating temp. Thanks again for your help, inputs and suggestions.

Up please! I would like to read your suggestions about using a different oil! Thanks

If it comes when cold and goes away I would bet on valve lifters for sure

These engines do NOT have lifter issues. Lifter issues that they do have are not “lash” issues, if anything the lifters fail the opposite way, which keep the valves from closing, leading to misfires. It takes lash to make a “lifter noise”. See this page on our site all about this failure.. Watch the video as well. All of these things are conclusiove, and we see this more than 50 times per year. This year alone our failure log has seen 115 cases of “lifter noise” that ended up being cylinder failures. Each year we see more of these reports than the year before, and most reports are made diuring seasonal, or fuel blend changes. Spring and fall are when the vast majority are reported. http://flat6innovations.com/cylinder-bore-scoring/

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Thanks for your comment Okay so now what should I do... I just bought the car in July 18'. Had a PPI done (Unfortunately I wasnt there while they were doing it and receive only the report) and everything was perfect. Drove about 1000kms until storage while respecting the engine (Proper warm-up, shift around 5500-6000rpms) Do you think there is a possibility I can take legal action again the garage who did PPI or previous owner if I discover a scored cylinder? I defenately would take a 3.8lts engine rebuilt by Flat6 but its something I can't afford at the moment....

No

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I don't think anyone can offer legal advice, but it's certainly a good idea to look into. Lemon laws vary by state if you're in the usa and the nature of the purchase agreement and/or warranty. I am in the same boat. I bought my car with scoring not knowing it had this issue AS-IS and I also do not have the funds to rebuild the engine atm. My options are: 1) Sell the car for a loss of ~6-7k. 2) rebuild the engine for ~8-10k. (Don't have the funds) 3) drive it until it dies, save, then rebuild the engine. Since I love the car and want to keep it for many years to come, I decided to drive it with the knock. Save as fast as I can then rebuild in another year. If I sold it and took a hit, I would at some point save to buy another one and potentially have this issue come up again. From what I understand an engine rebuild from F6 is better than a new engine, plus added power with the 3.8. Once everything is done, I think I'll look back and be happy I worked through it. All in I will have spent ~25k for a vehicle that costs over 100k new! Not a bad deal, just takes time and perseverance.

Here�s what i would do: Don't do anything other than checking for bore scoring by going into the spark plug hole and from the bottom by dropping the pan. It�s not your oil, or a myriad of stuff folks often go and replace, such as lifters, chains, IMSB, tensioners, etc. Don�t change the lifter or oil pump... It could be an exhaust leak or spark plug leak (your bore test will fish out the spark plug possibility), it could be an injector, it could be tensioners making noise (because they are last to get oil), oil pump or filter bypass could cause this too, even a coolant pipe knocking against something. When I start my car, for 5-15 seconds, no noise. Then I get a knock if I leave the engine idling. It stays for 1-3 mins and then goes away. However, if I drive off immediately, it goes away after 10-15 seconds. My bet is that it�s either bore scoring or the exhaust or something loose that�s not getting oil when cold, that expands due to heat or revs that allow for oil flow. The oil jets that lubricate the piston bottoms and lower cylinder on this car don�t work when cold and slow. Oil may not be present enough in the bore due to temperature and/or oil pressure/flow. Idling is not helpful, neither is flogging when cold. The oil weight you have in there is perfect. Please Let us know if the noise goes away if your drive off immediately and how for how long it takes. Please report what temp you see when/if the noise goes away.

When you asked for your PPI, did you ask that the sump be dropped and the engine scoped? If no, it is on you, totally. If you did, how would you even go about proving that they didn't do it...or did do it and found damage...or even heard the sound (after all, you've heard it 2x in a few months and it was likely started a couple times in process of getting to the PPI garage even if it went there on a flatbed). Talking about taking legal action on this with the PPI garage is silly. You knew you were taking a risk buying a 16yr old vehicle that is plagued by a number of inherent issues. Buying one of these after a good PPI is still somewhat of a crapshoot, albeit an educated one.

[QUOTE=MadIrish;15483516 Buying one of these after a good PPI is still somewhat of a crapshoot, albeit an educated one.[/QUOTE] Agreed. I am seeing less shops offering, or wanting to to these PPI's. I don't blame them.

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Calm down everyone. Talks of taking legal action against a shop because you have a slight tick for a few seconds after startup? RL is a great resource but we can sometimes over react and panic unnecessarily. On a cold start, the oil is going to be in the sump and will take several seconds to circulate through your engine. Ticking for a few seconds then going away would not cause me to be concerned especially in the colder winter months. Just drive off right from startup, not letting it sit and idle, then keep it under 4K rpms until the oil is up to temp. Just be sensible like you would with any other car.

Mine does that too first cold start , I'm convinced it's lifters but everyone says not but why would it just do it once on first cold start then never again all day until following next first cold start?? Is running ok for now so will check it out over winter , if it's got scoring going to strip it down (again ) and have Hartech put the 3.7 liners in with new pistons , that will sort it!

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you don't let it idle down to 850rpms? I let all my cars idle down before putting in gear and driving off.

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Thats what I meant. Fire it up and it settles after a second or two, then drive. I was referring to not letting the car sit for an extended period warning up before driving off.

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Do this. My ticking on cold start, driver side, went away. Never any noise when warmed up. I am replacing water pump, (feel a very little play) and possibly tensioner and iddler bearings. 5w40. 56k miles. X51. I burn about 1gt per 5k miles. I use all my rpms.😎

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If your engine doesn�t tick, that�s fine. If it does, I wouldn�t let it idle. Anytime something ticks, it could be from metal to metal contact, so if driving off reduces a tick, I would just drive off. Other benefits include lower emissions (cleaner air), less possibility for oil contamination (due to fuel getting past the rings), and less time the engine is running sub-optimally.

Hi thanks for your comments. I was talking about legal actions just because I dont understand how it happened after a complete PPI including bore scope. The oil pan was removed for the inspection as they charged time for redoing the scellant on the oil pan. I bought the car following their recommendations and that's why I was asking if there was some legal actions that can solve this kind of problem. After some research it seems that yes there is a last resort solution. In my provice the law state that a used car have to be trouble free for a reasonable amount of time and mileage after the purchase unless stated otherwise. I guess using the car for 1000kms and having engine bore scoring right after fall in this category especially after a complete inspection saying that everything was good. So in the end I will try to figure out what can cause this noise before starting this whole process and the first step will be bringing the car for a second bore scope inspection next spring. I also will take your advises on cold start-up. Since I got the car I always start-it, let the oil "work", wait until the SAI pump go off and the rpms go down before taking off. I let the temperature go up and steady for a couple minutes before going over 4000rpms. But if I hear the engine ticking noise I will just drive off without waiting for the rpms to come down. Also I would like to know if there's something I can do to minimise problems when starting the car for the first time after few months of storage? I already added gas stabilizer but nothing else was done to the engine. I will let you know if I found something interresting. Thanks

Yes, that "thicking" sound is alarming... I much prefer the "thinning" sound myself... carry on!

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Just said that to my wife... I dont understand why she dont want to see me anymore... Should have check the spelling before writing the title.. sorry about that

The spelling police will get you every time!

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Spelling errors are forgivable. But those that can't figure out when to use "then" and "than" I just wanna slap!

Then I spilled my guts...but better than losing my mind.

Just a quick follow-up on this old thread. I went for a spark plug change today and a borescope. Good news, no signs of scoring. The old plugs are all looking good and the pistons tops look good aswell! So I guess the cause lies somewhere else but the noise hasnt returned since the last video.

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Was the bore scope only done through the spark plug holes? If so, you only saw 1/2 of the picture, and not the most important part. If I don�t see Anything from this point of view, I go in through the sump to see the bottoms of the cylinders.

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It was done by the sump and by the spark plugs holes so the proper way! Decided to do it at the same time as the plugs and do both sides. I was there during the inspection just for peace of mind and pictures were taken. Should get them by tommorrow. The only thing we seen is a very small part on the top of piston #3 that is a bit more dirty than the other or the rest of his surface but I guess its not an issue. If I add to this equation the UOA done a few weeks ago with no fuel dissolution I can say Im safe one the bore scoring side for the moment I will cobtinue to apply your advise about driving and maintaining the car. Thanks!