7.3 loud thumping at start up.

[texcl]

If I leave the 93 na f-250 sit overnight in the cold, and I go to start it, it has a horrible thumping noise for about a second or two then the truck sounds normal for the rest of the day. It will only do this if it has been sitting over night or longer. It was so loud today I my son jumped away from the truck because he though the engine was going to blow. I can't pin point it since it only lasts a second or two and don't trust my kids to start it while i'm under the hood. have any of yall encountered this? I'm starting to think an engine mount is broken or there is valve to piston contact at start up, but it runs like a champ under all other conditions. Could one cylinder have a bad glow plug and not fire causing a temporary dead cylinder till it gets going fast enough to fire it on compression alone? would it cause a thud like that?

 

[sjwelds]

http://www.oilburners.net/forums/showthread.php?71713-Strange-noise-on-cold-start-up&highlight=

 

[texcl]

Geeze, if it's the lifters I'm just going to deadline the truck. Really don't want to have to tear the whole engine apart. guess for now it should be ok to drive since it doesn't make the sound when it's warmer. It was in the 20's this morning and it didn't do it at all. is it common for a 7.3 to get bad lifters around 250k miles? It has always had good maintenance from what I can tell and it gets it's oil changed with less than 3000 miles, shoot even use synthetic in it (minus the last season).

 

[sjwelds]

Yeah mine has 250k ish too. It hasn't made the noise for quite awhile now so I'm not worrying about it.

 

[texcl]

I guess the lifter is just worn and has to pump up after sitting, it's not collapsed so shouldn't be a big deal for a while in theory. So why does it not do this if plugged in? Wouldn't it leak down quicker if warm? Synthetic 5w-40 isn't that thick at 20-30 degrees so wouldn't think it would take that much longer to pump up. Thins truck need the front u-joints rebuilt and a new clutch, I'm thinking it's about time to just cut my losses and drive it till something blows.

 

[79jasper]

Another perspective:
Think of trying to suck cold gear oil through a swizzle stick vs warm synthetic.

Not exact apples to apples, but you get the idea.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[texcl]

So, found some nos ford lifters for $24 per 4. The valley pan is $50. How difficult is it to do the whole job.

 

[texcl]

Seems it was just varnish, switched back to synthetic and put 2 cans of JB engine tune in it to clean the lifters and the noise is gone.