Loud knocking in 2001 mustang GT 4.6

gt
damage
mustang

#1

I Need Help! I was stuck and had to drive through about 2 feet of water a couple weeks ago in the floods and my car hasnt been the same since. It died in the water and when I got it started to get it out of the water a loud knocking stared that increases with the RPM’s I changed the plugs and air filter that was full of water…the sound is still there. The tensioner on the timing chain was broken so I repaired but didnt replace that but the noise is still there. I’m thinking maybe the a lifter or a rocker arm. The sound isnt loud enough to be a rod I don’t think and my car has dual overhead cams so I don’t know for sure…but I don’t think it could be rod problem. Can anyone Help with this? Thanks so much in advance.


#2

It sounds to me like you hydrolocked the engine when it sucked in some of the water that you drove through. The breakage of the tensioner on the timing chain is a pretty good indication that you bent some valves, IMHO. If I were you, I would have the car towed to a competent mechanic, as further operation of the engine could lead to even more damage than you already have.


#3

When the timing chain tensioner broke, some valves may have gotten bent. Use the Chilton’s, or Hayes Mustang manual guide to do a vacuum test on the engine. It’s gotten difficult to do compression checks on all cylinders on v- engines, anymore; though it’s still possible. You could, also, pull the valve covers and check for excessive clearance in the valve train. A defect should show as a LARGE clearance between valves and rocker arm tips. Cylinder head(s) valve job may be needed.


#4

Water will not compress in the cylinders of your engine. Once it gets in there, one cylinder coming up toward top dead center is all it takes to bend a rod and destroy the engine. From the symptoms you described, that’s exactly what you have done. IF you hydrolocked the engine, your incident should be covered by your comprehensive insurance. The insurance company will probably total your car as it will cost them more to fix that it’s worth minus its salvage value. If you don’t have comp coverage, you really goofed driving into high water. See www.car-part.com for a selection of used engines in your area.

Don’t feel too stupid. One, obviously rich, guy in this area lost both his yellow Viper and his yellow Prowler to high water. His mistake was just trying to START them after they had been under water in his own garage. Someone forgot to tell him about the incompressability of water. All he’d have had to do was PULL THE SPARK PLUGS before cranking their engines.


#5

well the car is at a repair shop now and he’s saying that he really doesn’t think its a bent rod because the knocking isn’t loud enough and in fact its gotten quieter since its been there. Other then the noise it runs fine…doesn’t die when its running, rpm’s stay in range, etc…
If I had a choice about it, clearly I wouldn’t have been in water at all, and I wouldn’t have tried to start it except my car was completely blocking traffic on a 2 lane road.
The car was never totally submerged, it was fast moving water over the road from the river that runs by it at the start of the flood and at its peak was probably about 2 feet. My mechanic is still working on it but he’s getting stumped. Any more ideas?


#6

well the car is at a repair shop now and he’s saying that he really doesn’t think its a bent rod because the knocking isn’t loud enough and in fact its gotten quieter since its been there. Other then the noise it runs fine…doesn’t die when its running, rpm’s stay in range, etc…
If I had a choice about it, clearly I wouldn’t have been in water at all, and I wouldn’t have tried to start it except my car was completely blocking traffic on a 2 lane road.
The car was never totally submerged, it was fast moving water over the road from the river that runs by it at the start of the flood and at its peak was probably about 2 feet. My mechanic is still working on it but he’s getting stumped. Any more ideas?


#7

Hello,

Just wondering what you finally found out about your car and what was the solution ? The exact problem happened to me yesterday. The car is now in the shop waiting to be checked. The car starts and run normally except that the knocking is still there. Thanks.


#8

I think the knocking was due to water in the oil, An oil change might be in order here. Water makes a lousy lubricant and things will knock.