Engine Knock at startup

[Michaeljp86]

When I fire up my truck after about 5 seconds it slowly starts to knock and after about one min it goes away. It starts good and runs fine. Seems to be worse when its cold out. Any idea?

 

[Raleigh]

Sounds like a loose connecting rod to me, I had a 400 that did the same thing. Basically when the oil got to the bearing that was loose it quite down.

 

[Michaeljp86]

Sounds like a loose connecting rod to me, I had a 400 that did the same thing. Basically when the oil got to the bearing that was loose it quite down.

Thats what I was thinking, is that common on a 6.5L I dont drive it in the winter but I just put a water pump on it. I noticed it back in the summer but it was hardly noticable and slowly got worse. Before I put it on the road Ill pull the pan off and check it out.

 

[Crankme69]

Many things can cause a diesel to knock at cold start. I posted this same question about mine. Mine has been doing this cold (extreme cold it's worse) ever since I purchased it. I made it worse when I changed the IP timing TDCO to -1.85. You might want to consider sending in an oil sample for testing before you tear it apart...

HTH's

 

[Michaeljp86]

Many things can cause a diesel to knock at cold start. I posted this same question about mine. Mine has been doing this cold (extreme cold it's worse) ever since I purchased it. I made it worse when I changed the IP timing TDCO to -1.85. You might want to consider sending in an oil sample for testing before you tear it apart...

HTH's

sounds like mine, did you ever fix it?

I think the pan is easy to get off on a 2wd so I figured I would pull it off and see what I see.

 

[THEFERMANATOR]

Rod bearings knock on initail start-up until it builds up oil pressure(usually less than 5 seconds unless they are really bad). Lifters and val;vetrain tend to take a few seconds to begin to knock as they need to bleed down some. Without hearing teh knock it is hard to say as it could be an injector rattle, or a weak glow plug if it's cold enough out.

 

[Michaeljp86]

Rod bearings knock on initail start-up until it builds up oil pressure(usually less than 5 seconds unless they are really bad). Lifters and val;vetrain tend to take a few seconds to begin to knock as they need to bleed down some. Without hearing teh knock it is hard to say as it could be an injector rattle, or a weak glow plug if it's cold enough out.

I wouldnt think it would be a wore rob bearing because it came on to quick. Also it doesnt seem to be running on all 8 when you first fire it up in the cold. It used to fire right up and run smooth no matter the temperature. The colder it is the worse the knock.

 

[THEFERMANATOR]

I wouldnt think it would be a wore rob bearing because it came on to quick. Also it doesnt seem to be running on all 8 when you first fire it up in the cold. It used to fire right up and run smooth no matter the temperature. The colder it is the worse the knock.

If you have a bad glow plug, then the cylinder with the bad glow plug could knock pretty good for 20 or 30 seconds until it gets some heat into it and starts firing completely. Hard to say without hearing it as it could also be a bad injector allowing a line to bleed off and teh knocking sound is teh air clearing itself from the line on start-up.

 

[OrionThade]

Maybe post a video of the knock?

 

[Michaeljp86]

Maybe post a video of the knock?

Ive been planning one only problm is my camera doesnt have clear sound on the video. My moms camera is perfect but it quit working. If I can find the charger I have another camera that takes realy good video on a mini dvd.