[ZachsV6]

Hopefully, someone can help me figure this out.

My engine vibrates, it always has for the last 120k miles. I've had the car since 30k. It is only engine vibration. I have triple checked everything else and it happens whether i rev the engine, drive...no matter. The vibration is coupled to the engine speed.

My car was built on June 7, 2000. It has a BA in the suffix of the engine code meaning that the engine has a 2001 shortblock. (According to Ford)

Questions:

1) Are 2001+ 3.8's internally or externally balanced? Tom Morana says that all 3.8's are externally balanced but i've heard conflicting stories that 2000 engines are ext balanced and 2001 are int balanced.

2) Anyone else have this problem on a 2000 mustang?

3) Anyone heard stories of the wrong flexplate and harmonic balancer being installed from the factory. e.g.; if my engine is internally balanced after all, would/could ford have put on the wrong balancer and flexplate and should I switch them to 2001 parts.

4) ANY other clues toward a solution to this vibration.

Thanks in advance.

-Zach

[Safi]

Could be worn out motor mounts

[El_Cangri]

+1 on the motor mounts

[ZachsV6]

Already checked the motor mounts and tranny mount. They were fine, both in good shape, but I replaced them anyway about 15k miles ago. The vibration didn't change at all.

I've also done a compression test and all cyl's are within a few percent of each other. A tad lower than spec but that's to be expected on a motor with 150k on it.

-Zach

[Matt.]

mine vibrate a little more then ushally at 65-75 mph but not anything bad, but not that big of a problum. From 10-70ish and 80-120 Its perfect. Also noticed the same for my brother's S4. Could also be your brakes if it shakes alot when you aply them at higher speeds.

[ZachsV6]

I've checked. The brakes are new. I checked the runout on the hub and rotors to cancel out tolerance stacking just for that reason.

The car has IRS. The pinion angles have been set. The runout on the pinion flange and pinion yoke were checked and the driveshaft was balanced and indexed. The wheels were balanced and all suspension rubber in the front is new. Aside from the IRS subframe bushings, there is no rubber left in the rear, only aluminum and Delrin. Every source of vibration that could arise from the drivetrain was checked and checked again, documented and then fixed. The only vibration left in the car is the engine.

I'm almost to the point where I am going to drop the pan and see if the crank is fully bobweighted. If it is, then my shortblock is internally balanced and has the wrong HB and flexplate. I'm probably going to do that regardless unless someone knows for certain that there are some mismatched engines out there in the 2000 mustangs.

I only have to make the motor last for about 6 more months and then it's replacement will be ready. But until then I have to drive it every day. Given that I have tracked down every other vibration in the car, it just makes the engine vibe that much more annoying.

-Zach

[99 BLUE V6]

Originally Posted by ZachsV6 Hopefully, someone can help me figure this out. My engine vibrates, it always has for the last 120k miles. I've had the car since 30k. It is only engine vibration. I have triple checked everything else and it happens whether i rev the engine, drive...no matter. The vibration is coupled to the engine speed. My car was built on June 7, 2000. It has a BA in the suffix of the engine code meaning that the engine has a 2001 shortblock. (According to Ford) Questions: 1) Are 2001+ 3.8's internally or externally balanced? Tom Morana says that all 3.8's are externally balanced but i've heard conflicting stories that 2000 engines are ext balanced and 2001 are int balanced. 2) Anyone else have this problem on a 2000 mustang? 3) Anyone heard stories of the wrong flexplate and harmonic balancer being installed from the factory. e.g.; if my engine is internally balanced after all, would/could ford have put on the wrong balancer and flexplate and should I switch them to 2001 parts. 4) ANY other clues toward a solution to this vibration. Thanks in advance. -Zach

Could be your balancer is coming apart. Or is lose on rubber.Or it could be a tuning problem.Have you ever put plug wires on it.Has it been this way since you bought it .My 99 is external.

[Peanutman_87]

If you find out PLEASE let me know my 99 does the same thing around 1000 to 1500 rpms and it drives me nuts i cant figure it out

[g96|38|T5|220K]

Originally Posted by ZachsV6 I've checked. The brakes are new. I checked the runout on the hub and rotors to cancel out tolerance stacking just for that reason. The car has IRS. The pinion angles have been set. The runout on the pinion flange and pinion yoke were checked and the driveshaft was balanced and indexed. The wheels were balanced and all suspension rubber in the front is new. Aside from the IRS subframe bushings, there is no rubber left in the rear, only aluminum and Delrin. Every source of vibration that could arise from the drivetrain was checked and checked again, documented and then fixed. The only vibration left in the car is the engine. I'm almost to the point where I am going to drop the pan and see if the crank is fully bobweighted. If it is, then my shortblock is internally balanced and has the wrong HB and flexplate. I'm probably going to do that regardless unless someone knows for certain that there are some mismatched engines out there in the 2000 mustangs. I only have to make the motor last for about 6 more months and then it's replacement will be ready. But until then I have to drive it every day. Given that I have tracked down every other vibration in the car, it just makes the engine vibe that much more annoying. -Zach

my 96 3.8 has 233K miles and massive vibration at times and certain rpms. it started to around 180K and its getting worse. feels decent under WOT at temp. i think it started with a massive rear wheel hop on a 2nd gear WOT pull at 50mph. seems like the rain or high moisture lowers the vibration. when i pull the accessory belt the damn thing feels like brand new engine. wish i could drive it without that belt... it is externally balanced and this has to be the harmonic balancer causing this, even if it appears to be fine. ford dealer had no idea, said the harmonic balancer is fine and told me to use higher rpms. possibly the autozone power steering pump? try pulling the belt and starting it briefly. any more than a minute without the water pump might be trouble.
i found a forum with a guy that had this same issues replacing everything but the HB and that turned out to be his issue. even if it has not turned or moved or changed in anyway it can be too far gone?
what you guys think?

[Green_6er]

My car vibrates all of the time. but then again my exhaust is welded to the chassis with no rubber in between anyway, i would check the balancer and if you have a manual get the flywheel resurfaced.

[g96|38|T5|220K]

Originally Posted by g96|38|T5|220K my 96 3.8 has 233K miles and massive vibration at times and certain rpms. it started to around 180K and its getting worse. feels decent under WOT at temp. i think it started with a massive rear wheel hop on a 2nd gear WOT pull at 50mph. seems like the rain or high moisture lowers the vibration. when i pull the accessory belt the damn thing feels like brand new engine. wish i could drive it without that belt... it is externally balanced and this has to be the harmonic balancer causing this, even if it appears to be fine. ford dealer had no idea, said the harmonic balancer is fine and told me to use higher rpms. possibly the autozone power steering pump? try pulling the belt and starting it briefly. any more than a minute without the water pump might be trouble. i found a forum with a guy that had this same issues replacing everything but the HB and that turned out to be his issue. even if it has not turned or moved or changed in anyway it can be too far gone? what you guys think?

Figured it out. I was finally able to compare the Harmonic Balancer with a different one and it looked like the weight was right where it should be so i put a old cracked up serpantine belt on and its fixed. NO vibration through all gears 1200 - 5000 rpm, no shaking at idle. I guess my newer replacement belt had gone bad about 180K miles [shortly after i put it on] and it was vibrating the accessories like crazy with different engine speeds. 238000 mile 3.8ltr runs like it just rolled out of the factory again! I waited a while to get my 35mpg back! I think there is like 30 different forums with people chasing this same problem with this engine and none ever find it.
I was starting to doubt the beast 3.8 but now all i can do is hope that i find a new motorcraft belt. Now i have no doubt this mustang will see 300K or more miles on this original motor.

[Skargon]

35Mpg? What do you do, 10MPH everywhere? ._.;

[01Lightning]

I have the same issue, I wouldn't call it a problem.
I have an 01 V6 with 113,000 miles.

Under 60mph, no shaking.
Accelerating from 60 to 70, shaking
Driving at 70, no shaking
Accelerating from 70 to 80, not sure...
Driving at 80, no shaking
Accelerating from 80 to 90, no shaking
Driving at 90, no shaking.

That's my experience, may not be exact, it's been a while since I went on the highway in my Mustang. It's not a big deal to me. I thought it was something in the AC that was loose or shaking, because it sounded like it was coming from really, really close to me, like closer than the engine is.