a strange noise coming from an NHC250 water pump

[steelcaptain]

with coolant level low there was no noise coming from the water pump but after filling cooling system all the way, the water pump is making a noise something between a squeal and a grind. noise seems to be at all rpms but as the engine rpm drops, the noise momentarily goes away then returns when rpm stabilizes. coolant appears to be circulating in the system fine. it is not the belts

any thoughts if this is a bad water pump or something else in the front gear drivetrain?

 

[glcaines]

Sometimes you can have an air pocket in the water pump. The impeller isn't pumping the coolant properly and it makes noise.

 

[steelcaptain]

Sometimes you can have an air pocket in the water pump. The impeller isn't pumping the coolant properly and it makes noise.

that did occur to me as a possibility but thought after being run long enough the air would get pushed out of the pump and make its way to the overflow tank? this went on for 10minutes until I shut the engine down and decided to ask on here for advice

 

[simp5782]

Or a plastic impeller that has broke apart and its hitting itself

 

[frank8003]

work on it

 

[Crf450x]

I would at least pull it out and look at it. Mine locked up going down the road and it didn’t even make noise. If you take it off you will likely need a new seal even if you don’t replace the pump.

 

[steelcaptain]

Or a plastic impeller that has broke apart and its hitting itself

please tell me these engines don't have plastic impellers...

 

[simp5782]

please tell me these engines don't have plastic impellers...

Some do. Some don't. Just depends on what they used

 

[steelcaptain]

Some do. Some don't. Just depends on what they used

well to me the sound seemed much more like metal on metal

 

[Floridianson]

Ever put some grease in the grease fitting?

 

[steelcaptain]

I see no grease fitting and the lubrication order for the M809 trucks doesn't mention there being one

 

[juanprado]

The shaft seal could be suspect allowing the shaft and impeller to be scrapping the block.

Pulling the pump might be in order. I have only seen metal impeller. The design is just plain stupid and lots of work.
I have the Copper crush seal and the plate gasket if you need.

Change belt anyway if you take it down
No sense in reusing it.

There is no grease fitting.

 

[Floridianson]

The shaft seal could be suspect allowing the shaft and impeller to be scrapping the block.

Pulling the pump might be in order. I have only seen metal impeller. The design is just plain stupid and lots of work.
I have the Copper crush seal and the plate gasket if you need.

Change belt anyway if you take it down
No sense in reusing it.

There is no grease fitting.

Would you like to put some money on that?

Water pump question

I have a M923 with a NHC-250. The water pump has a grease fitting on it. I had a moment of stupid hit me while I was greasing the truck and greased it without first checking what grease to put in it. A few days later found the antifreese was milky . Could the grease have gotten into the into the...

www.steelsoldiers.com

 

[simp5782]

Some have fittings. Some don't. Depends on who made the pump

 

[Floridianson]

Could believe that but every 5 ton 250 I had had the grease fitting.

 

[Crf450x]

Could believe that but every 5 ton 250 I had had the grease fitting.

Mine doesn’t...

 

[EO2NMCB]

please tell me these engines don't have plastic impellers...

My 927 did, busted in half.

 

[Floridianson]

Wonder if they switched when the 939 series came out. All mine were 809 series mid 70's.

 

[Ajax MD]

I see no grease fitting and the lubrication order for the M809 trucks doesn't mention there being one

There absolutely is a grease fitting on my water pump.