rattling and overheating

[RZinKY]

My 99 3500 box van has a bad rattle and wants to run hot under a load or heavy throttle. The truck has 220,000 miles and prev owner said GM replaced the motor under warranty at 100,000.

I was going to have the waterpump replaced but after reading post about the harmonic balancer, belt tensioner, and pulleys was thinking of replacing it all.

Is there anything else I should consider changing while in there. I plan on owning this Boxvan for along time and it is very tight working in there.

Thanks Jeff

[Robyn]

Are you seeing any coolant loss?
Is this Rattle a mechanical sounding rattle or more in the line of a harsh Diesel combustion rattle?

If it mechanical sounding try removing the belt/belts and running it a for a short to see if the sound goes away or changes.
A bad water pump will make terrible noises when idleing or just above.

Let us know more

Robyn

[RZinKY]

It has lost very little water. The rattle comes and goes. Seem like every time I take it to a shop it is not rattling. With these vans you cannot see the engine and its hard to tell where the rattle is comming from.