Cammer
Well-Known Member
- Joined
- Aug 16, 2016
- Threads
- 1
- Messages
- 53
- Reaction score
- 63
- Location
- Portland, OR
- Vehicle(s)
- 2016 Shelby GT350, 2001 F-150 Lightning
- Thread starter
- #1
Late last week my car developed a really loud metallic rattle at 1800 RPMs. Above or below that and the rattle went away.
I had the hood open and had an assistant rev the motor to that RPM and it sounded like it was coming from the head or block (driver's side) which of course had me worried. It didn't add up to an imminent engine failure since I had good oil pressure and the rattle was so RPM-specific.
In any case, I finally got the car up on the QuickJack and set to work locating the source providing it wasn't an internal engine problem.
Long story short, the driver's side exhaust damper (the big orange rubber one) was completely loose as its nut had backed off a good 1/2" (the stud the nut threads onto is about 1" long). Apparently 1800 RPMs creates a resonance that causes maximum vibration in that part of the exhaust.
It seems to me that this is inevitable since the damper is secured by that nut and blue loctite - no lock washer or jam nut. I checked the passenger's side and it wasn't loose, but was way too easy to turn with a ratchet. I applied fresh blue loctite (don't know how effective this will be since it's going to get hot there) and tightened both nuts pretty hard. I'm going to get some jam nuts so that the next time I'm under there, I install them as I can see this happening again and again.
Anyway, just a heads up for you guys. If you're under your car, you should check your dampers!
Brian
I had the hood open and had an assistant rev the motor to that RPM and it sounded like it was coming from the head or block (driver's side) which of course had me worried. It didn't add up to an imminent engine failure since I had good oil pressure and the rattle was so RPM-specific.
In any case, I finally got the car up on the QuickJack and set to work locating the source providing it wasn't an internal engine problem.
Long story short, the driver's side exhaust damper (the big orange rubber one) was completely loose as its nut had backed off a good 1/2" (the stud the nut threads onto is about 1" long). Apparently 1800 RPMs creates a resonance that causes maximum vibration in that part of the exhaust.
It seems to me that this is inevitable since the damper is secured by that nut and blue loctite - no lock washer or jam nut. I checked the passenger's side and it wasn't loose, but was way too easy to turn with a ratchet. I applied fresh blue loctite (don't know how effective this will be since it's going to get hot there) and tightened both nuts pretty hard. I'm going to get some jam nuts so that the next time I'm under there, I install them as I can see this happening again and again.
Anyway, just a heads up for you guys. If you're under your car, you should check your dampers!
Brian
Sponsored
