Possible engine problems?

[COBALT]

While driving home the other night I heard a sound I haven't heard in a while. The last time I heard something like this my rear-end differential was about to crater. This time it sounded like it was right in front of the firewall, or under my feet. A scraping/chirping sound. Metal on metal. A slight dragging like a tiny loss in power.

I swapped the transmissions recently (two months ago) for a new TH400 I had rebuilt by a shop. It's been shifting like a dream with no leaks so far. I'd hate to think it was the transmission, but I'm also worried it might be the motor.

There's some noise with the truck in park when I give it some gas, so it's not the driveline or the rear-end. It might be the torque converter, but it's a new one. MAYBE an accessory like the water pump or power steering??? I'm super worried. This 350 has a lot of miles on it, and I'm wondering if I spun a rod bearing or something. It started happening after I gave it some gas to pass someone, and was later driving away from a stoplight.

I'm going to start checking the truck out as soon as I get some time (and it stops gushing rain on me). I need to check all the fluids, and see if I get any clues from a cold start. Any ideas from you guys on ways I could diagnose this would be helpful.

[70c10]

Maybe it's a cable bouncing around or something minor. Take your time and check all linkage, etc. Good luck with it.

[jhow66]

Check your TQ convertor bolts.

[VetteVet]

These noises are tough to find sometimes. I've heard the sound you describe and it has usually been a worn out bearing I.E. water pump, alternator front bearing, wheel bearing, or worn out clutch not in your case. Try loosening the fan belts and see if it goes away. I know you will find it but it could be time consuming. Good luck VV

[Wrenchbender Ret]

How about the carrier brg. in the drive shaft.

[crazy longhorn]

I agree with all posted......also, you might look for a broken flex plate( i have heard that 1 called a "rodnock" many times. best of luck, L

[COBALT]

Originally Posted by VetteVet

These noises are tough to find sometimes. I've heard the sound you describe and it has usually been a worn out bearing I.E. water pump, alternator front bearing, wheel bearing, or worn out clutch not in your case. Try loosening the fan belts and see if it goes away. I know you will find it but it could be time consuming. Good luck VV

It's not a wheel bearing. last time I had a fan belt make a squealing it didn't sound like that. Lets put it this way...the sound made me let off the gas and get concerned...

[COBALT]

Originally Posted by Wrenchbender Ret

How about the carrier brg. in the drive shaft.

It's not that. It's happening when the truck is sitting still in park.

[COBALT]

Originally Posted by crazy longhorn

I agree with all posted......also, you might look for a broken flex plate( i have heard that 1 called a "rodnock" many times. best of luck, L

I thought about that. When I did the transmission swap the flexplate looked good. I lubed up the hub on the torque converter so things like this wouldn't happen, but who knows. Torque converter bolts are a good idea, only this came and went. I assume it would get nothing but worse if either of these were the case.

As far as rod knock...it didn't sound like a knocked in time with the ignition.

[COBALT]

Update:

After an extremely busy two weeks at work I finally got the chance (in between rain storms) to get out to the truck (that's been parked on a side-street since I live in the city) and try to figure out what's going on.

Here's what I found:

1. Engine oil was low, but looks normal. No water in it. The usual clear dark brown. No debris.
2. Coolant was WAY low. I haven't checked it in a while (since the end of summer). I had to dump almost a 1/2 gallon of 50/50 mix in. I haven't had any problems with temperature, and it likes to dump out the overflow if I keep it full, so I intentionally don't keep it full all the time.
3. Transmission fluid looks clean (although I haven't let the truck warm up, and cycle through the gears enough to find out if the level is right yet).
4. Transmission still looks clean as a whistle. No breaks in the pan gasket. No overflow from the dipstick. I see a tiny bit of leak out of the rear seal, but I've never been able to keep that from happening with my crusty slip-yoke. It likes to eat seals, so I think that's ok.

When I fired up the truck the sqealing began almost immediately, and it suddenly comes and goes. Sounds like an over-tightened belt when I'm standing in front of the truck. Sounds like it's comming from the front of the engine.

I'm guessing either:

1. Alternator, but I'm getting good amps
2. Water pump (most likely because of the coolant level, and it's an old pump)
3. Power steering

I loosened up both the alternator and power steering belts - no change in the sound.

I know I have a leaky oil pan gasket, but I haven't been loosing that much oil so I'm waiting until I pull the motor for some other stuff before I fix it.

I need to get this truck warmed up and take it for a spin before I know more, then check the transmission and oil again. I was hearing a different sound when I was driving, so I have to see if it's still happening...

More later.

[COBALT]

Oh, and I have a fuel leak. The fuel line between the pump and the filter is cracked, and leaking fuel. Gotta fix that first before I move the truck...

[COBALT]

I don't think anyone is reading this, so I'll just keep going.

I yanked the alternator, and it sounds like it has gravel in it when I spin it, so I'm replacing that now. Fuel leak is fixed. Once I get it all back together I'm going to see if the noise goes away. Next on the list of replacements is the water pump if it's still making noise.

[71-longbed]

Sounds like your making good progress despite the rain .... i dont have a garage either so i know how you feel ... 9 months out of the year ...

Try removing the power steering belt and making a short trip around the block ....

good luck and keep us posted

[dwaite72lnghrn]

That alternator was most likely the problem. a bearing going south will cause the rubbing noise and if it seizes quick it will feel like you hit a head wind all of a sudden then go away.

[shortbed70]

If you take the bolts out of the convertor and the belts off and it still does it pull the pan and check the rods. I just rebuilt a 6.2 and it had a squeal and it turned out to be a rod bearing spun but had no knock. Good luck.

[68haywagon]

Originally Posted by dwaite72lnghrn

That alternator was most likely the problem. a bearing going south will cause the rubbing noise and if it seizes quick it will feel like you hit a head wind all of a sudden then go away.

Or it stops the motor when it seizes. Been there, done that!!

Mike

[COBALT]

Replaced the alternator. No more noise.

NAPA had remanufactured ones for '69, but the first one was clocked 180 degrees out so I had to spin the housing to get it right. Then of course it turned out to be a bad alternator for some reason. Back to NAPA to get another one...

Damn it! They were closed! I had to wait until this morning to go back. I bring in the bad alternator and they don't believe me that it's bad. So the guy behind the counter decides to proove me wrong by going in the back and testing it...um...where was that test when I bought the damn thing?

He comes back, and says "Uh...it is bad. Wow." Yeah. Wow.

I didn't leave the store until they had tested the second one AFTER I had reclocked it to the right setup. It worked great, so I took it home, wired it up, bolted it in, and no more noise.

I don't think it'll be that easy though. I'm waiting for the other shoe to drop.

[71-longbed]

cobalt the pessimist... good luck

[VetteVet]

Originally Posted by COBALT

Update:

After an extremely busy two weeks at work I finally got the chance (in between rain storms) to get out to the truck (that's been parked on a side-street since I live in the city) and try to figure out what's going on.

Here's what I found:

1. Engine oil was low, but looks normal. No water in it. The usual clear dark brown. No debris.
2. Coolant was WAY low. I haven't checked it in a while (since the end of summer). I had to dump almost a 1/2 gallon of 50/50 mix in. I haven't had any problems with temperature, and it likes to dump out the overflow if I keep it full, so I intentionally don't keep it full all the time.
3. Transmission fluid looks clean (although I haven't let the truck warm up, and cycle through the gears enough to find out if the level is right yet).
4. Transmission still looks clean as a whistle. No breaks in the pan gasket. No overflow from the dipstick. I see a tiny bit of leak out of the rear seal, but I've never been able to keep that from happening with my crusty slip-yoke. It likes to eat seals, so I think that's ok.

When I fired up the truck the sqealing began almost immediately, and it suddenly comes and goes. Sounds like an over-tightened belt when I'm standing in front of the truck. Sounds like it's comming from the front of the engine.

I'm guessing either:

1. Alternator, but I'm getting good amps
2. Water pump (most likely because of the coolant level, and it's an old pump)
3. Power steering

I loosened up both the alternator and power steering belts - no change in the sound.
I know I have a leaky oil pan gasket, but I haven't been loosing that much oil so I'm waiting until I pull the motor for some other stuff before I fix it.

I need to get this truck warmed up and take it for a spin before I know more, then check the transmission and oil again. I was hearing a different sound when I was driving, so I have to see if it's still happening...

More later.

I'm puzzled , if you loosened the belts and the alternator quit turning ,why did the sound not stop? Anyways glad you got it fixed. V V

[GMan69]

Glad you were able to fix it. I was going to suggest checking your harmonic damper. Happened to me with a '84 Pontiac. (305 sbc)

[COBALT]

Originally Posted by VetteVet

I'm puzzled , if you loosened the belts and the alternator quit turning ,why did the sound not stop? Anyways glad you got it fixed. V V

You gotta remember - this was the ORIGINAL alternator. It's 37 years old. The bearing was completely shot. At that point it wouldn't have mattered whether the belt was loose or not. It was definitely worse with the belt tightened up.

Cobalt the pessimist? LOL

I've become a pragatist since working on this truck. I fix one thing, and it uncovers two other problems...I just got tired of celebrating.