9165pt0

Just picked up a fox recently. Prior owner said his wife drove onto a parking barrier, and possibly the radiator was raised up. I checked the radiator support and everything seems to be pretty straight. However, the fan does his the shroud slightly. The fan scrapes the bottom of the shroud. I adjusted the shroud, to where it doesnt hit however the fan just barely clears the bottom of the shroud. I believe the motor mounts to be good, the motor doesnt shake or jerk etc.

Idk if its related, but there is a vibration coming from somewhere. it happens while car is in park and I rev the motor between 1000-1200rpm. Anything higher or lower is fine. When the car is idling in drive, is feels rough with vibration as well, but in park and idle its fine. I cant make sense of this. I have heard it could be the harmonic balancer, I did have it off to do a timing chain and cover gasket last week. Could it be something went wrong on the install?

1991 Mustang GT

just a few questions
I'm assuming you just got it (relatively recently), since you brought up that the 'previous owner said...' and you are now asking questions - and that you haven't been driving it this way.
I would think you'd be able to know if they hit something so hard, that it would mess up the drivetrain (IE, does it get 'worse' when driving)... otherwise, its not in your drivetrain, or motor mounts. And instead it would be in your shrowd (spelling)

5-sp or AT?

Moving on to your 2nd paragraph, were the symptons any different before hand?

EDIT - my mind skipped right over your initial sentence of you purchasing it recently

9165pt0

thanks for quick reply. Yes i bought it 2 months ago, and just drove it home. Parked it and let it sit until i had time to fix a few leaks it had. I really dont recall the vibration being as bad before. I do remember idle was always not so smooth. It idles good, and hte needle is on point etc, its just the motor feels a lil rough like a slight movement every second or two.

9165pt0

Also no nothing gets worse when driving, and there is no damage underneath the vehicle etc. I believe the previous owner may have ran something over, and related the fan hitting the shroud because of that. I dont see an signs of damage, yet the fan barely clears the bottom. And there is def a vibration, yet the mounts seem fine and engine sits pretty still. Only at 1000-1200 rev in park, and normal idle is there that darn vibration and roughness. really wierd

mattdel

Check fan blade for cracks and any signs that it's just not right, then while the engine is off grab the fan clutch and pull it up/down/left/right, checking for play in it & the water pump shaft bearing.

Your vibration sounds like a misfire to me.

dawson1112

Like matt says check the fan out for any cracked or bent blades. When was the last tune up with new plugs wires cap and rotor done?
A bent blade will cause a vibration as well as a cracked one. Also does it still have the stock fan on it or is it one of those flex fans?
A for the HB as long as you used the correct tools to remove and install , it should be ok . Was the vibration there before you did the timing chain? You can look at the balancer while the car is idling and see it if it wobbling . It is a common problem on the 5.0 engines that the rubber in the balancer goes bad and it slips or causes a vibration.

9165pt0

heres more info, i believe the balancer is ok then. Ill check it today, when i reinstalled the balancer and tightened the nut down it spun a lil bit turning the motor. But the balancer doesnt wobble, however Ill get under it and double check.

As far as tune up, it has new plugs, cap, rotor and wires and fuel filter. Everything gapped at .54, autolite copper plugs. But on the ntumber 8 spark plug, some genius stripped the threads. On cast iron stock heads, a lil mind boggling. Only a few middle threads are stripped, and I was still able to get the new plug in pretty snug and tight. No hiss of air or miss coming from there. Yet if the vibration sounds like a miss to you guys, maybe it is the problem. Is there a way to check and eliminate which cylinder is misfiring?

Now to the fan, the bearing and shaft is nice and tight, also new water pump. But yes, the tips of the fan blades are worn down. No crack, but definatley a small portion of the tips has worn or broken away. At idle the fan seems to spin freely and doesnt look wobbly or off balance. Could it still be bad, if not visible?

9165pt0

btw it is the stock fan. and i dont remember the vibration at 1000-1200rpm when revving before. But the idle always seemed a lil rough. Doesnt sound like a vac leak rough, the needle stays still and the rpms are steady. Bet way i can describe it is, it just seems to shake every second or 2. like a duh-duh and then idles smooth then duh-duh.

9165pt0

Just checked out the car today. The balancer has a slight wobble, but the crank pulley has no wobble. AS for the mounts, the passenger side motor mount bushing part has cracks and seems to have come apart a lil bit. A neighbor had me hold the brake pedal down and apply some throttle to see if motor jumps or moves up, it does not. ???

dawson1112

The balancer wobbles like that because the rubber that is between the inner and outer sections is probly worn out . Some one on here last week had one that came completely apart.