Anybody getting a faint knocking sound from engine when cold?
#1
Cobra R Member
Thread Starter
Join Date: November 10, 2004
Posts: 1,601
Likes: 0
Received 0 Likes
on
0 Posts
Anybody getting a faint knocking sound from engine when cold?
I just noticed it this morning, but then it went away when the engine was warmed up. I revved on it a few times after it was fully warmed up, and nothing at all. This all happened when I took the GF to work early this morning, and she said that she could hear it faintly too. It's not the first time I've ever heard it, so I was wondering if this is normal..........if not, then I'm still under warranty for another year yet.
#4
Just a W-A-guess, but this reminds me of something I had when I installed my CAI. There was a leak in the breather tube to the passenger's side cam cover. What this did was to interfere with the variable cam timing. It needs vacuum to function. At idle it was knocking. Underway, no problem. Fixed the leak and no problems since.
You might want to check for vacuum leaks.
You might want to check for vacuum leaks.
#6
I just noticed it this morning, but then it went away when the engine was warmed up. I revved on it a few times after it was fully warmed up, and nothing at all. This all happened when I took the GF to work early this morning, and she said that she could hear it faintly too. It's not the first time I've ever heard it, so I was wondering if this is normal..........if not, then I'm still under warranty for another year yet.
#7
Legacy TMS Member
Do you guys have the manual transmission or an automatic?
If it is the manual transmission, I can hear a rattling noise when the clutch is out (engaged with flywheel). The engine itself sounds very smooth and quiet.
If it is the automatic, then I dunno...
If it is the manual transmission, I can hear a rattling noise when the clutch is out (engaged with flywheel). The engine itself sounds very smooth and quiet.
If it is the automatic, then I dunno...
#10
Mine does it. Sounds like its coming from the pulleys or belt. I just put my stock pulleys back on to see if that makes a difference. It is strange because it goes away completely when the engine warms up.
#11
I have noticed this faint 'knocking' sound as well. Honestly though, I'm really not that worried about it. I don't want to take it to the dealer because chances are they'll create more problems just looking for the noise. I don't think it's an issue
#12
Legacy TMS Member
After the engine was fully warmed up, I heard the ticking sound as well. My 4.6 2V V8 does it when fully warmed up, but the 5.4L 2V V8 in the van doesn't make this sound.
As soon as you open the throttle, the sound disappears.
As soon as you open the throttle, the sound disappears.
#13
Mach 1 Member
I have stopped listening to mine. Misty ticks, whines, and clicks all the time. I noticed when I installed my CAI, but I never listened that closely before the CAI so when I got worried I returned it to stock and it was the same. This is by far the noisiest car I have ever owned, and that’s part of the charm I suppose. So long as I do not hear anything different or sudden, I’m not going to sweat it!
Tim
#15
It could be loose clearances in the engine that tighten up when the engine is warm. GM LT1's and LS1's have had a problem with piston slap that usually disappears when the car is warm. Since the engine block and heads are aluminum with over head cams, you'll likely hear more noise than you would on a comparable iron block engine with over head valves. As long as the noises disappear when the car warms up, it is probably normal, unless you have a chain tensioner issue that has been mentioned in the TSB.
#16
i just noticed it this morning in mine. Its a clicking sound and not at all a metallic sound like the transmission inspection plate that many of us can remember. This will need some further inspection.
#17
Legacy TMS Member
I hear the ticking sound only when the engine is fully warmed up. It sounds just like my Romeo 4.6 2V V8. The Windsor 5.4 2V V8 in the E-250 is silent/smooth.
#18
I put my stock pulleys back on and the noise is gone. I will put the Steeda pulleys back on in a few weeks and see if it comes back. The noise I had was really loud and may not be the same one that others were hearing.
#19
Legacy TMS Member
If the Steeda dampener is smaller than the stock diameter dampener (not the ribs where the belt rides), it can allow some vibrations to be undampened, leading to oil pump gear failure (at least on the 2V engines) at high RPMs. Make sure you torque the crank pulley bolt properly (If it is a TTY bolt, follow the procedure). It's easier to torque properly with a manual transmission than with an automatic.
#20
Join Date: January 30, 2004
Location: DMV
Posts: 2,980
Likes: 0
Received 0 Likes
on
0 Posts
Knocking noise might well be just a bit of minor piston slap when the motor's cold. As mentioned, the aluminum GM LS motors had similar issues. AL, IIRC, has a bit more thermal expansion than FE, thus, the tolerances are thus a bit looser when cold to accomodate this. Add to this that AL tends to transmit noises a bit more than FE and the generally looser, friction-reducing tolerances on today's motors and voila, a bit of knock on those chilly mornings. Take it a bit easy on the poor gal till she warms up and, presuming the sound fades away on warmup, no real issue.
Ticking noises could either be a slightly sticky HLA (hydraulic valve lifter) or even just the fuel injector actuation noise sneaking past. If a very light sounds, probably no issue. If a bit louder, and suspecting a sticky or clogged lifter, you might try an engine oil flush to clean out any offending grunge. The HLAs can have some pretty tight clearances and internal passages, so it doesn't take too much to gunk them up a bit.
Ticking noises could either be a slightly sticky HLA (hydraulic valve lifter) or even just the fuel injector actuation noise sneaking past. If a very light sounds, probably no issue. If a bit louder, and suspecting a sticky or clogged lifter, you might try an engine oil flush to clean out any offending grunge. The HLAs can have some pretty tight clearances and internal passages, so it doesn't take too much to gunk them up a bit.