Possible Rod Knock

[1952Chevy]

As in my introduction https://www.gmt400.com/threads/hellloooo.53119/ post I have a 99 K2500 454 with a possible rod knock.

I drained the oil, it had about 12qts instead of 7. A few flakes, but nothing that would point out obvious bearing problems. No discoloration of the oil, it was just dirty.

Today, using a stethoscope, a friend and I tried to locate the sound. The closer you get to the transmission the louder it gets. I am thinking possibly a cracked flex-plate/ loose torque convertor bolt.

I attempted to remove the inspection cover from the torque convertor area, but cannot fully remove it without removing the exhaust. Of course that's giving me problems.

Any other recommendations until I am able to remove the exhaust and check the flex-plate/torque converter?

 

[Schurkey]

Cut open the oil filter.

Most likely:
Metal dust or pieces = crank problems
No metal dust or pieces = Flexplate

WHY was the oil overfilled? Coolant contamination? Fuel contamination? Just plain too damn much oil?

 

[1952Chevy]

It didn't seem like coolant contamination, possibly fuel? I put new oil in and monitoring the level closely while I do troubleshooting.

I also noticed the oil press gauge reads about 70psi at Idle. I don't believe it is actually that high. Thinking about replacing the oil pressure sensor and seeing what that says, or getting a manual gauge hooked up.

 

[Supercharged111]

It didn't seem like coolant contamination, possibly fuel? I put new oil in and monitoring the level closely while I do troubleshooting.

I also noticed the oil press gauge reads about 70psi at Idle. I don't believe it is actually that high. Thinking about replacing the oil pressure sensor and seeing what that says, or getting a manual gauge hooked up.

Mine will read about there when cold. Warm it's closer to 40 at idle and 55 cruising.

 

[1952Chevy]

That's good to know. I have a hard time believing it would be a bearing with oil pressure like that though.

Tempted to just take a sawzall to my exhuast to get that inspection cover off. Eventually I plan to go true dual exhaust anyway, but in the meantime I wouldn't have a chunk of my exhaust.

 

[someotherguy]

If it was that much over-full and ends up being due to fuel, that's a serious amount of dilution and likely the bearings are toast. :/

Used oil from a gas engine always has a fuel smell (to my nose, anyway) but I'd expect quarts worth of fuel in the oil to be extremely obvious to the nose...?

Richard

 

[letitsnow]

If you cut the exhaust fairly cleanly, you could buy 2 band clamps to reinstall.

 

[Pinger]

Used oil from a gas engine always has a fuel smell (to my nose, anyway) but I'd expect quarts worth of fuel in the oil to be extremely obvious to the nose...?

Richard

Yep, to the point you'd be checking which end of the truck you'd drained from.

 

[1952Chevy]

If it was that much over-full and ends up being due to fuel, that's a serious amount of dilution and likely the bearings are toast. :/

Used oil from a gas engine always has a fuel smell (to my nose, anyway) but I'd expect quarts worth of fuel in the oil to be extremely obvious to the nose...?

Richard

Yep, to the point you'd be checking which end of the truck you'd drained from.

The fuel smell wasn't that strong. It was faint or just my nose playing tricks. I'm wondering if the PO just added oil when he heard the knock.

If you cut the exhaust fairly cleanly, you could buy 2 band clamps to reinstall.

That's kind of where I'm at thinking that might be my best bet.

 

[TIM GAINOUS]

X 2 on oil filter inspection.

 

[1952Chevy]

So I did cut the exhaust section out cleanly to be able to weld/clamp back in place. Flexplate and torque converter/bolts all look fine, nothing loose. Of course with the exhaust removed it's not louder and harder to hear the knock.

Still can't pinpoint the sound, but it's in the block somewhere. I attempted to pull plug wires one at a time, on the drivers side cylinders, no change. Haven't done the passenger side yet. Next step is passenger side, and cutting open the oil filter.

After that I'll drop the oil pan and inspect the rods/bearings.