Stumped Ford Ranger 3.0 noise

Helping a friend repair another friend's 94 Ranger with 3.0 V6. Truck was overheated and barely ran when it showed up at my house, that's about all the history I have on it.

Tore it down, found cracked head and the radiator was crap. So we got some reman heads and a new radiator and put it all back together.

Now its running, sounded good at first but after a few seconds we started getting a random knock noise from the motor, sounds almost hollow and is fairly loud. It is not entirely RPM dependent, meaning it does not occur in time with the rotation of the motor but it does seem to increase somewhat (although not proportionally) with the speed of the engine.

We are also still burning some coolant but I think that's an unrelated issue at the moment.

The only thing that comes to mind for a random but semi related to rotation would be a broken rod. Please have some other ideas before we tear this puppy back down again.

How I got suckered into this I dont know....

In reply to JThw8:

Water pump. This popped up on my Escort and I nearly went crazy trying to track it down.

I hope it is this simple for you, but it is where I would check given the facts related.

Bruce

egnorant wrote: In reply to JThw8: Water pump. This popped up on my Escort and I nearly went crazy trying to track it down. I hope it is this simple for you, but it is where I would check given the facts related. Bruce

Well we do have a spare so it's worth a look but I put a mechanic's stethoscope on it and didn't hear it from the water pump. But the stethoscope didnt pinpoint any other location either.

The thing that is driving me nuts is its not in "time" with the motor. Considering something caused it to overheat to crack the heads in the first place and the radiator was bad but not terrible that could well be it.

I always have more luck with a long screwdriver than a stethoscope, idk that it actually makes sense for that to work better though lol

Loose flywheel ? Cracked flex plate ? Try isolating each cylinder in order, eliminates or locates bad rod.

corytate wrote: I always have more luck with a long screwdriver than a stethoscope, idk that it actually makes sense for that to work better though lol

Well, it was a screwdriver ;)

iceracer wrote: Loose flywheel ? Cracked flex plate ? Try isolating each cylinder in order, eliminates or locates bad rod.

We didnt do anything to touch the flywheel so it's unlikely but not impossible, like I said I dont know what the condition was prior to it's arrival at my place.

My 1st thought was water pump.

Spark plug?

Had one blow out on me in Lincoln at nationals. The sound before it blew out was like a lifter tick, but with the timing/rhythm of a rod knock. Drove me and my codriver nuts trying to figure out what it was.. and then it let go entirely.

Edit: Not sure if that's the same sound you're hearing since your description is a little vague(understandably so though)

I'll take Water Pump for $300 Alex.....

Definitely going to take a shot with the water pump next time we can work on it. One had already been purchased since initially I was told it was a 2.3 4 cylinder so I figured if the head was coming off we should do the timing belt, water pump etc while we were in there.

When it arrived at my house and I found the V6 under the hood I told my buddy who was taking care of parts ordering to get the stuff for the 3.0 but neglected to tell him we didnt need the water pump anymore, so we have it.

It is a really odd sound, I should have recorded it but we started tearing it back down so I can't fire it up right now to get a recording.

Well, buddy came over today and swapped the water pump. No Joy. But at least I was around when he fired it up to record the noise. It doesn't sound pretty.

http://www.youtube.com/watch?v=7osvKuTyTRQ&feature=youtu.be

You may have an exhaust rocker off, or a lobe gone. Pull the valve covers and roll the engine over.

Electric fan?

Streetwiseguy wrote: You may have an exhaust rocker off, or a lobe gone. Pull the valve covers and roll the engine over.

I'm starting to lean this way. Nothing against my friend but I first caught him putting the rockers on backwards at first and the noise sounds like it was coming from the side he assembled. I'm guessing a pushrod may not have made it into its lifter bore correctly. I should have checked everyone's work but I was splitting my time between 2 people's cars at the same time and assuming everyone had done this before. I'll be pulling the valve covers next free day I get.

Well I finally got a chance to get under the hood of this tonight so I thought I'd give everyone some closure.

My last guess was correct, a pushrod that didnt hit its mark on getting to the lifter and was wedged down in the hole. Ugh.

So it runs quietly now, slightly rough but we just eyeballed timing so I wont sweat that just yet. Also a little smoke out the exhaust...not sweating until the timing is set, may just be burning off crud...honestly I stopped caring long ago, I just want this out of my driveway.

Of course I run it up to temperature and then go for a spin around the block and.... Ugh..I know why it overheated and blew the headgaskets, the heater core is whizzing all over the interior, how the owner did not know this is beyond me, but the condition of the truck pretty much says "owner doesnt care" which is why I've stopped worrying about making this thing perfect. Going to bypass the heater core and tell him to come get his truck, it runs now, probably better than it did before.