I think I have a knock in my motor, its an 89 Non Intercooled motor. Now iv been told that they just sound like that but to me it sounds like a Knock in the lower end. So my Q is how can you tell the diff between a Knock and a Diesel? let me know what yall think..

 

A rod knock you will hear when you rev it up and let off, it will make noise when it's unloaded. You won't hear it while you are increasing the RPM, only when the RPM is falling off.

A lower end knock on an automatic is often a cracked flexplate.

 

Where is my Flexplate?
And I here it when I hit the gas hard and when its falling off but not when im holding the RPMs high and stedy

 

The flexplate is what connects the engine to the torque converter. It also has the teeth for the starter. It is a common failure point on older dodges. Both my ramcharger and my gas pickup finally cracked the flexplate...and neither truck made anywhere near the power of the cummins I highly doubt you have an engine knock, but have the oil pressure checked with a known good gauge and check the oil for coolant contamination, just to be safe. Unfortunately, flexplates can be very tricky, and the sound on a cracked one can be difficult, if not impossible to diagnose. Even when out of the vehicle, a crack can be very hard to spot. I don't know much about the diesel autos, but I hear there's an updated flexplate...might be woth checking out. Hope this helps.

greg

 

Greg im not sure ether but if I wanted to check my oil presser how can I go about doing that. Not to sound dumb I just dont know how? Is this something a shop can do and can it be any shop or does it need to be a diesel shop?

 

fist u got a plug on top of you oil filter ether hook up a temporary mecanical gage there or a permanent mechanical gage

 

Can I buy a permanent mechanical gage at an auto part store and how do you install one just screw it in?

 

Any 'parts store' mechanical oil psi gauge will work...there's a spare place to tap in on the top of the oil filter housing, or you can unscrew the factory gauge sender under the injection pump on the left side of the block and plug in there temporarily. Though good oil pressure does not rule out a knock, it can be reassuring to see the gauge go up even though the factory gauge seems to barely move Any reputable shop should be able to check that for you if you'd rather not tackle it yourself. As for the correct number, I can't remember but 20 psi hot in drive would be acceptable in my mind.

FWIW, I put 15k on my ramcharger with a flexplate rattling so loud it sounded like a wrist pin was about to come through the block! Some of that was towing a 5k trailer. Coulda swore the engine was toast, but it was just that stupid plate

g

 

The parts store gauge will have a compression fitting...should have instructions....the fitting should be tight enough, but not too tight

g

 

Im sorry for all the Qs im just new to Diesels and im very worryed about my truck
Ill check in to a gauge tomarrow, Is that tap ontop of the oil filter is that a good place to mout a permanent oil pressure gauge? Or should I use the same hole the stock sending unit went?

Also how much will a good aftermarket gauge run me and how long to install oh and is it somthing I can do my self?

 

I wonder.....have you tried to localize the noise..I mean, are you able to find or narrow down the area that is producing the noise????? It would really help if you could.
You can use a piece of wooden dowel or a piece of garden hose.............oh ya....here's a warning for you.....be VERY careful were you stick that piece of garden hose....I nearly smacked myself silly one day.....Ooooooo...that baby left marks dude..

pb....

 

.....be VERY careful were you stick that piece of garden hose....I nearly smacked myself silly one day.....Ooooooo...that baby left marks dude..

pb.... [/B][/QUOTE]

 

Two seperate issues here that you have confused. A flexplate will knock pretty much all the time.

A rod knock (bad connecting rod bearing) will only knock when the engine is unloaded, as in when you let off the accelerator.

 

I bet it is a rod knock can that be fixed or is that a rebuild?

 

If the crank isn't tore up too bad you can do it with the motor (mostly) in the truck.

Before you panic, get an oil analysis done. If there's a bad bearing, the analysis people will tell you. A bad bearing puts a lot of lead, tin, and silver in the oil.