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YOUR RESEARCHNew purchase bore scoring and bad clutch
Leading reported evidence
Run 1/3 coolant
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Leading evidence: 'Run 1/3 coolant' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check with a parts store' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Anyway when I drove it home from Wisconsin 1300 miles I ran two Techron treatments and I took it past 150.
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My advice is to not listen/get anymore opinions on it until you have tested/done the two things I have mentioned. Then either get more opinions or talk A LOT about how it fixed your problem.
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Check with a parts store
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Suggestion
Here is your sign.....That clean area that has the shinny spots is there because there is not enough clearance to the head.
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What is the mileage ? I have 140k on mine and it acts the same way with a tick from the passenger side, sometimes its there fairly pronounced, other times it's quiet as a mouse.
I took it to my Porsche Indy who was in the middle of replacing a block for bore scoring. He said it did not sound like bore scoring, citing the car he was working on as a comparison for the noise and not to worry about it.
So I haven't.
YMMV.
You Tube
Here's a cold start of mine from a few years ago
The 99 3.4 is not as bad about bore scoring as the newer models. It has iron coated pistons ( Ferrostan) ..
Go to the local auto parts and buy a $20 Mechanics Stethoscope and listen to the catalytic converters while the sound is evident, compare bank 1 to bank 2...
Also get a can of Sea-Foam or CDI combustion chamber cleaner and follow the directions. It only takes about 1mm of carbon build-up on the piston crown to cause a very very similar knocking sound.
We just had a Rennlist member a few months ago with the same sound on a 99 3.4 that everyone's opinion on it was bore-scoring. It was not bore-scoring was just carbon build-up..
My advice is to not listen/get anymore opinions on it until you have tested/done the two things I have mentioned. Then either get more opinions or talk A LOT about how it fixed your problem.
The only advice I took was from my Indy :shrug: which was not to worry about it. I'll be trying your carbon build up reduction methods and seeing what happens to my high mileage 3.4
......and listen to your catalytic converters. The "cat guts" are made of precious metals and ceramic and can make a sound like a little German guy with a small hammer taping on your engine.
It can even take on a cadence and tempo of the engine RPM and a single cylinder.
I have the 99 that Porsche Tech is taking about. Buy the CRC GDI, disconnect the hose from air box going to throttle. Spray the whole content while someone tries to keep rpms at 2,000. The instructions say to let it sit for an hour to soak. I did 1.5 hours. After that drive it away it will smoke white, once everything gets to
operating temp drive it at highway speed for at least 10 minutes. Welcome to the club. I bought mine with 91,000 miles in January is already past 97,000. Listen to Porsche Tech 3, the man is an encyclopedia on our cars. What�s the production date on yours?? Luis in Texas.
I used this instead of sea foam because when I was working all the CRC products that we tested were great, also the straw nozzle is a lot heavier, the one on sea foam is too flimsy. Also run fuel system cleaner in your gas tank.
My car was only driven 3,000 miles in the 5 years prior to me buying it. The oil cap had yellow condensation on it. Anyway when I drove it home from Wisconsin 1300 miles I ran two Techron treatments and I took it past 150. Anyway it seemed that the more I drove it the stronger it got. I believe we did the CRC treatment at 3,000 miles of ownership. If the shop told you not to worry I would try driving it, running good fuel, etc. If you do a bunch of research most cars that have problems have not been driven much.
400?
Find an excuse to go somewhere. Get that baby out on the road and let it stretch a little. Road Trip!
If it's something that is possible to "clear up", it needs a legitimate opportunity to.
Whatever it is, it's likely not a grenade with the pin pulled.
If the noise disappears when you apply throttle, I don�t think it�s bore scoring. Maybe a stuck lifter?
Regarding noises, I like the post by Hartech on this page (basically saying not to worry about them):
https://www.pistonheads.com/gassing/...t=1285949&i=20
Blue is my favorite color. I had to settle for Silver but this was the best car with the best maintenance and a bunch of mods. Also probably at the time the best bang for my money.
Very nice blue 996! Mine is blue too (Zenith).
I noticed this thread as I am experiencing exactly the same behaviour on my 3.4 (1998 C2 manual).
Sometimes there is a ticking noise and sometimes not. Car has no black or smokey exhaust tip(s) en uses no oil.
When I switch on the aircon or push the throttle the sound is gone immediately.
So that doesn't sound like bore scoring to me.
Car drives fantastic and I use if a lot.
@MitchellArthur
: So the knocking/ticking is way less frequent now you used the CRC Intake valve cleaner?
Harry my ticking is gone. Due it. A clean engine is an efficient engine. I love the blue but when I was looking for my car couldn�t find one at the right price. Anyway the more I drive mine the more I love it.
Good eye. Could it be that the CRC treatment did its job and now the engine is running smoother, so the tapping is less frequent?
I hope it is something as simple as this!
Take the bumper out pull the condensers from the radiators then clean. After all of that use a chemical foam to clean the radiators condensers, you�ll definitely see lower temps.
Take the bumper out pull the condensers from the radiators then clean. After all of that use a chemical foam to clean the radiators condensers, you�ll definitely see lower temps.
Regarding oil pressure, it�s probably just increasing temps that appear to make your pressure drop lower and lower. My hot idle oil pressure ranges from 1.5 to 2.5, depending on how hot the oil gets.
If you are really bothered, put an oil pressure gauge on the engine to make sure your dash gauge is accurate or not. And then switch to 5w-50 oil for the summer, which will bring up your oil pressure by at least 0.25, which is more than enough at hot idle, and enough to keep the oil light from coming on.
The dash gauge on my car sometimes sits below zero, at zero, or above zero on my car on any random given day when the engine is off. The swing (delta) is off by almost 1/3rd bar and corresponds to my readings as such.
My oil pressure at idle is usually about 2 bar. But the other day I was driving in 90 degree weather and extremely slow traffic for 30-40 minutes. My temp was halfway between 180 and the next tick, which is before the 250 mark. But more alarming, was my idle oil pressure was just over 1 bar. I was pretty worried, but once I got out of stop and go traffic, the car cooled down to just above 180 and my idle oil pressure was back to about 2 bar.
Btw, the oil pressure light never came on.
i got my mechanic to pull the front bumper and we cleaned real good between the radiators and condensers, I also sprayed with chemical foam cleaner, plus we put a New resistor in one of the fans. Anyway now in 99 degree weather high humidity on stop and go traffic my water temp never goes past the 0, my car would get past the zero before and I was concerned about it.
since I honestly don�t worry about freezing 🥶 over here. I run 1/3 coolant
to 2/3 water, that helps dissipate a lot more heat. Also and I don�t know if that it�s available today redline makes a product call water wetter, if I find that product I�m dumping it in my coolant tank too.
Right. Clean radiators only help with efficiency when the fans or running, or when air is moving through the radiators. Stop and go traffic doesn�t produce much airflow.
All these 911s have temps that increase in stop and go traffic. Been happening since the 1980s, continues to happen today. Fans or airflow at speed are the only ways to control the temps.
Here is your sign.....That clean area that has the shinny spots is there because there is not enough clearance to the head. Either the head has a very hard build-up on it that the piston is tapping on, or the piston skirt has too much clearance ( from being scored) and is rocking enough that the piston rocks enough to contact the head and make the tapping sound...
Scope from the bottom to confirm.......
Here is your sign...
Makes complete sense. I will be over seas for a month so it�ll be a while before I can scope the bottom, I tried a month or so ago but it�s so tricky to get up in there. I have a new thinner scope so hopefully that helps.
Does the engine only make contact with the head at and tap at idle with the ac off because it would have enough time for the clearance or friction to tilt the piston during its stroke? Versus not making contact when it�s moving faster from the ac being switched on or with revs?
