Ticking, rough idle (not an exhaust leak)
 

hi guys...I have a 2000 GT, has gears, a little exhaust work, some intake work, and a tune. Have had a ticking sound for awhile now that's gotten progressively louder, but still not just super loud - just annoying. Thought it was exhaust - had it checked out and he said its not leaking anywhere. It's just started to idle pretty rough too. Otherwise, the engine pulls very strong without hesitation. No CEL. The tick is consistent with engine speed. What are the other options? I don't think it's a fuel injector or the engine would hesitate on acceleration right? Does this sound like something sticking in the valvetrain? He used a stethoscope and seemed to think it was somewhere in the head or maybe injector, but it was just a lube/exhaust shop so he offered no fix. Any thoughts?

tough one... maybe to thin of oil?
what kind are you running?
had this problem with my beamer, and i blame switching from RoyalP to another brand of full Syn.

Exhaust leak would be my first choice--they can mimic all sorts of mechanical noises, have someone else check it out.

It could also be a sticking/collapsed HLA, or a sticking valve, have someone who knows their shít do a vacuum test, that will show up any sort of valve train issue. The other thing to do is a dry compression test, if any cylinder comes up short do a wet test and see if that jug improves--that would indicate a sticking/burnt valve...

So is the engine shaking and by how much? Is the noise coming specifically from the front by the engine or more from underneath the car?

I think if it is an exhaust leak, it's where the manifold meets the motor, but the guy said he couldn't find it leaking anywhere. The ticking is definitely more noticeable when you are underneath the car. I wouldn't say the idle is super rough, but you can see the engine kind of shake every few seconds when it's idling and you can hear the exhaust kind of burble when it does that. The ticking is very consistent with engine speed. At a certain rpm I can no longer hear the tick, but that might be my exhaust drowning it out. It's not like the car dies at stoplights or anything. The tach needle might jump a little bit, but it's not on the verge of dying at idle. And, as I said, the motor pulls very strong still..no missing at all.

I'm having this thought of it possibly being the flywheel. Part of me kind of thought the ticking was coming from that area. Plus I have had some chatter and slight vibrations from that area lately. it shifts fine and there's no slippage, but probably a tad bit of vibration through the clutch pedal. And - I've had 2 or 3 starts in the last few weeks where the motor would not turn over - crank - crank - crank - fail- then - THUD. A very noticeable bang, in a way, at the end of the failed start. ??

The symptoms are pretty much showing exhaust leak to me, because most of what you've been describing was exactly what I experienced on my old 2000 and it was a crack by the exhaust manifold in a "well". The shop that found it for me did a $30 weld job and it ran perfect again. But they also did a smoke test for me too which was still even tricky to find.

But now that you've mentioned starting failure and a "bang" noise then it seems to be something more serious.

Well...I guess I'm not 100% convinced it's not an exhaust leak. I wouldn't say his inspection of the car was all that detailed. He didn't do a smoke test or anything like that. So who knows. I don't know about the start thing. The car starts fine 99% of the time. Just a couple of times I got lazy and didn't let it crank over all the way, let off the key too soon and the flywheel made a noise. I don't know.

What kind of oil do you have in your car?

5.5 quarts of 5W-30. Usually Pennzoil

I am not a very mechanically inclined person, but I had similar symptoms to yours.

It started out as a small "Ticking" noise. Nothing horribly obnoxious, just a constant tick. Almost like sticking a card in a spinning bicycle tire. The tick would be present at idle, and disappear through some RPM ranges, and be more present in others. The ticking got progressively worse, but would change the RPM ranges it presented itself in. It was now not present at idle, and only present around 3500-5000 RPM. It was progressively getting worse. It got to the point where it became very loud and obnoxious, a loud knocking noise. Upon starting the car, it sounded wretched. Like something was directly hitting the engine wall. Finally, I was driving to school one day, and the car was making atrocious noises and constantly shutting off. I had the car towed. The engine is now out of the car, waiting for a new engine. The cause, a thrown rod.

When I first heard the noise, I took it took one mechanic. He told me to try to put thicker oil in. This certainly made the tick quieter, but did not fix the problem.

I took the car to another mechanic, a very high end mechanic. He took his engine scope out and poked around the hole engine. He told me it could of been one of three things. 1)The dreaded rod knock. 2) A broken piston skirt. 3) A stuck lifter or an oil clog. Thinking it was most likely option three, I was instructed to run the vehicle extremely rough. After returning back to him after a few days of extremely rough driving, he took another look at it. The noise was much more present, and he could declare it was coming from the bottom end, and most likely a rod knock.

When the engine is running it is difficult to pinpoint the exact location of a malfunctioning sound, as the other engine parts pick up the reverb. Even though my car was throwing a rod, a malfunctioning sound was coming from the driver side top end.

Like I said, I am not a very mechanically inclined person, and I am sure there are a million other things that could be causing your problem.


I did learn some things that can cause A car to throw a rod:

Running the car on low oil for a long period of time.
Overheated engine