Rod Knock? what do you think

[StryctNy9e]

Recently I got my truck stuck in a deep mudhole/puddle. I have a 1993 XLT 140,000 miles and it runs strong. When I hit the hole the truck died, the water was not as high as the intake and when I restarted the ex it had a knock. I have not noticed any difference in preformance. I changed the oil and there was no metal or water and it looked like the normal 3000 mile oil. I tried the screwdriver to the ear trick , but my ear is not tuned and I cant tell where it is coming from. All I can tell is it sounds like it is coming from the driverside heads or block somewhere. Any suggestions. I couldnt figure out how to post the video so heres the link to you tube. Tell me what you think.

http://www.youtube.com/watch?v=YdkA_ZdtaYk

 

[StryctNy9e]

also I forgot to mention that the idler/tensioner pully is squeeking and I am going to replace asap. I also plan on taking off the belt to narrow down the possibilities of the knock.

 

[unclemeat]

Have you checked the air filter? That will tell you if water entered through the intake.

 

[jd4242]

Eww that dont sound good.sounds like you got some water in there and bent something or wore out a bearing from over reving.put a real oil gauge on and see what the psi is

 

[joecrna]

Check that air filter. Sounds like classic water lock = bent valve, rod or damaged piston.

 

[StryctNy9e]

put in a new air filter and it was really dirty but no major water in the box a couple drops or so. Looks like I need to save some money.

 

[BWTGUY]

My vote is for the exhaust leak. Check the header bolts and look for a cracked/broken manifold "ear" that the header bolt goes through. If you cannot see any damage, run the engine and listen for a sssssklog noise. Either way, it is a nasty fix. Just cheaper if a header is cracked/broken rather than a pretzle shaped connecting rod...

 

[StryctNy9e]

If I check th compession on the motor will it show indications of rod/bearing failure. I am making a list of to dos and things to check for tommarrow Any suggestions will be appreciated. Also I notice no lack of preformance would bad rods cause a lack of performance or would it run normal. I did check the exhaust manifold and didnt notice any cracks but I will double check it tomarrow. I will also remove spark plug boots 1 by 1 to try to narrow results and take off belt and run for a miniute to see if there is any improvements.

 

[unclemeat]

I listened to your youtube post, and it sounds like something very bad, like a bent connection rod. That mean a new motor.

 

[jd4242]

Check the oil pressure!!

 

[StryctNy9e]

oil pressure is 60 psi at 2000 RPM. Also no change in noise when I remove belt. Also remover spark plug boots individually and no change in noise. Ran out of time and I will check the compression soon. Any more suggestions?

 

[jd4242]

60 sounds high to me..how did you test it?

 

[StryctNy9e]

took out the oil pressure sensor directly from the block and bought a oil pressure gauge. Hooked it up and had my girl rev while I watched the gauge. Haynes manual says 40-60 psi @ 2000 RPM.

 

[StryctNy9e]

does anyone know what the compression should be? Or if it would be affected?

 

[Roadrunner777]

That sound is mechanical. You say someone may have over-reved the engine? (Does the computer limit revs?) It sounds like valvetrain to me, I'm going with a bent rod. I would take off the valve covers and look things over. I might do this sooner than later, if it is an exh valve, you could be burning it up by running the engine.

 

[StryctNy9e]

I will pull the valve covers soon to check it out. This car is my daily driver and I am saving for a new engine already, Just in case it is a worst case senario, rod knock. It will probably be a week or so before I can do it. But I will drive her gently, and will be on vacation for 3 days.

 

[Facimeor]

a bent rod might show a change in compression, but I doubt it. Generally by removing spark you take the pressure off a bad rod bearing, but with a bent rod that trick wont work, further supporting that theory.

Someone else mentioned the screwdriver stethescope trick but I personally like a wooden broom handle for that method of finding a noise. I have an old broom handle I cut into two different lengths then sharpened one end a little pinpoint where Im testing. Then wrap your hand around the end of the handle with you pointer finger just beyond the end of the handle. This makes a little sound chamber, to then put your ear up to.

Be careful around moving belts and fan blades but use that method and put the pointy end against different parts of the block including from underneath against the front and back of the oil pan and bottom of the timing cover area, and against the intake manifold and valve covers. Try to narrow down where the noise is loudest. My guess is you will hear it loudest from the oil pan.

That method is also good for checking timing chains, and front rotating masses like alternators, power steering pumps and water pumps to narrow down bearing noise.

p.s. If it is rod knock and if you intend to try to rebuild that motor I would HIGHLY recommend parking it immediately until you can tear it down. Even driving it easy you run the risk of tossing off the rod and ending up with a boat anchor. If your plan is to swap a used motor, then you can limp it for a short time, but dont expect it to last long.

 

[StryctNy9e]

Facimeor thanks for the advice. I did the screwdriver trick and it does seem loudest at the oil pan. Im pretty much tired of wasting time and money trying to figure it out. I found a used motor with 126000 miles on it for $600. Im gonna check it out after I get back from vacation next week. Im just gonna tell myself the eingine is pretty much toast and swap it out. I am gonna damn sure take the oil pan off once its out and take a look and find out what has caused me all this headache. I appreciate everyones advise and if anyone else has advise feel free to keep on posting suggestions. Thanks

P.S. I would like to buy a already rebuilt block , but not in my budget right now. Also I would like to do my own rebuild since I do have the time just dont have the space.

 

[unclemeat]

$600 is a lot for a used motor. I would not pay over $400.

 

[StryctNy9e]

Really? Everbody around here wants $600-800 with average milage around 125000-185000. I will try to talk them down and do more searching in my area for another motor. Thanks