Engine/Transmission (1994 - 1998) engine knocking, please help

[RJPotts]

Alright,

I'm going with a friend of mine to look at a 1995 3500 12 valver with 189,000 mi.

I haven't seen the truck and have no info on it other than its knocking.

Dunno if its knocking bad or just a little or what the "knock" sounds like.

I would just like some ammunition to take with me when we go to look at it.

What are some reasons a 12 valve would knock (more than normal)?

And how can I know for sure or at least have a good idea as to why it would be doing this?

Thanks in advance and the more help I can get before 4:00 p. m. eastern time on 6/30 the better.

-R. J.

 

[GAmes]

I've heard that when the lift pump starts going bad it makes noise (it's mechanical you know). I've also heard they are good for about 200k, that's why I've been carrying a spare for over 100k.

 

[BigPapa]

Check this out:



https://www.turbodieselregister.com/forums/showthread.php?t=129994



Scott

 

[RJPotts]

I just got some more info on this "knock".

From what I understand it is BAD, or at least sounds really bad to someone that has no clue about diesels. The owner says that we can't crank it and leave it at idle because he thinks it will come apart, this leads me to believe that it is shaking the whole truck pretty violently.

Any ideas on what could cause this???



The only thing I can think is a cylinder or two (maybe companion cylinders) just not getting fuel at all for some reason.



Any other options. Please, anyone and everyone throw your two cents in, I have to leave to go lok at this truck in 2 hours. (4:00 pm eastern time)

-R. J.

 

[Vaughn MacKenzie]

There is an off chance the truck had a Fram filter on it and one of the cooling nozzles is plugged and a cylinder is screwed up. That always makes 'em knock loud. Would not buy without checking it out in person and doing a compression check (or seeing how much vapor comes out the blowby).



Vaughn

 

[RJPotts]

He changed his mind. We went and looked at an 01' 2500 5-spd.

I didn't think about that. I used a Fram ONCE before I found out that they were bad news (changed my oil at 2000 miles that time) I guess I got lucky.

Thanks for the help anyways,

-R. J.

 

[bmoeller]

A spun rod/main bearing can knock pretty bad, too.