rovorster
New Member
Hey all. I have a 2003 Mach 1 with about 130k miles on the clock, use it mostly for spirited weekend driving and commute about 2 or 3 times a week. Since ownership have changed the oil every ~6 months or so (probably around 5k miles) and have had no issues with the car. Recently it started to make a rattling noise and I can't quite place it, these are the symptoms:
- Sounds like a metal rattle, reminds me of the cold start lifter tick my Miata used to have.
- Most noticeable around 2.5k RPM, not there at lower RPM's but at higher RPM's it's still there
- It comes in once the engine starts to warm up (~2-3 mins into driving)
- It's there only under light load, if I'm off throttle or giving it just a bit more gas (like over a quarter throttle or so) it disappears completely. It'll consistently be there under e.g. light throttle on the highway when going slightly downhill. If I freely rev the engine you can hear it very shortly when the revs are on the way down.
Revving it under the hood, it sounds like it's coming from the back of the passenger head underneath the hood, but it's pretty hard to pin down. I tried firmly holding the shaker and that didn't seem to make a difference. The car is definitely not down on power and feels healthy. Only problem I noticed recently was when I changed the spark plugs a while ago; one of them seemed to have a bit of oil on the plug wire, figured it was just one of the seals and not a major deal. From some initial research seems like it could be:
- A rod bearing (very worried about this one because I'm afraid I'll need a new crank)
- Some kind of valve lash/lifter issue. But then I'd really expect it to show up specifically when the car is cold, and it's the opposite of that.
- Timing chain tensioner? Again would really expect to hear this only when the car is cold.
- Clutch in/out makes no difference, definitely sounds like engine internal to me.
Anyone have any other ideas or heard a similar noise? I love this car and am willing to put in the money to keep it running. Plan is take the timing chain cover off over the weekend to look at the tensioner + take the passenger-side valve cover off and hopefully find something.
- Sounds like a metal rattle, reminds me of the cold start lifter tick my Miata used to have.
- Most noticeable around 2.5k RPM, not there at lower RPM's but at higher RPM's it's still there
- It comes in once the engine starts to warm up (~2-3 mins into driving)
- It's there only under light load, if I'm off throttle or giving it just a bit more gas (like over a quarter throttle or so) it disappears completely. It'll consistently be there under e.g. light throttle on the highway when going slightly downhill. If I freely rev the engine you can hear it very shortly when the revs are on the way down.
Revving it under the hood, it sounds like it's coming from the back of the passenger head underneath the hood, but it's pretty hard to pin down. I tried firmly holding the shaker and that didn't seem to make a difference. The car is definitely not down on power and feels healthy. Only problem I noticed recently was when I changed the spark plugs a while ago; one of them seemed to have a bit of oil on the plug wire, figured it was just one of the seals and not a major deal. From some initial research seems like it could be:
- A rod bearing (very worried about this one because I'm afraid I'll need a new crank)
- Some kind of valve lash/lifter issue. But then I'd really expect it to show up specifically when the car is cold, and it's the opposite of that.
- Timing chain tensioner? Again would really expect to hear this only when the car is cold.
- Clutch in/out makes no difference, definitely sounds like engine internal to me.
Anyone have any other ideas or heard a similar noise? I love this car and am willing to put in the money to keep it running. Plan is take the timing chain cover off over the weekend to look at the tensioner + take the passenger-side valve cover off and hopefully find something.