2000 Sterling loud howling engine noise??

[b2bomber]

Hello all... First time owning such a truck and first time posting here. Got a 2000 Sterling with a CAT 3126B Diesel, Allision Auto, 200k on the odometer and 24ft bobtail. Seems to be a good running truck and the only complain I have so far is the loud howling engine noise as I press the accelerator and speeding up. The louder the noise the higher the RPM, idling noise seems normal. With the windows closed I can barely hear myself talk with RPM at around 2.5k (WOT) at 55mph. Is this a problem with the fan clutch or something? The truck does not overheat and stays around 195 degrees. My 2000 Ford E350 V10 gas engine does that once in a while during cold mornings (40 degrees in Los Angeles) but once it's warmed up, that howling noise goes away and the engine really quiets down nicely. This is the best comparison I can throw out as I have no idea why the CAT diesel makes such a loud noise which is unbearable.

Also, the engine tops out at 55mph and 2500rpm unless I'm going down hill and maybe 60mph if I'm lucky. Is there a way to bump up the top speed to 70~75mph with a ecu mod? I'm in the Chino/Inland Empire area, does anyone know where I can take the truck in for service? Thanks!!!

[379Longhood]

Originally Posted by b2bomber

Hello all... First time owning such a truck and first time posting here. Got a 2000 Sterling with a CAT 3126B Diesel, Allision Auto, 200k on the odometer and 24ft bobtail. Seems to be a good running truck and the only complain I have so far is the loud howling engine noise as I press the accelerator and speeding up. The louder the noise the higher the RPM, idling noise seems normal. With the windows closed I can barely hear myself talk with RPM at around 2.5k (WOT) at 55mph. Is this a problem with the fan clutch or something? The truck does not overheat and stays around 195 degrees. My 2000 Ford E350 V10 gas engine does that once in a while during cold mornings (40 degrees in Los Angeles) but once it's warmed up, that howling noise goes away and the engine really quiets down nicely. This is the best comparison I can throw out as I have no idea why the CAT diesel makes such a loud noise which is unbearable.

Also, the engine tops out at 55mph and 2500rpm unless I'm going down hill and maybe 60mph if I'm lucky. Is there a way to bump up the top speed to 70~75mph with a ecu mod? I'm in the Chino/Inland Empire area, does anyone know where I can take the truck in for service? Thanks!!!

does the noise change under load if so could be turbo related, you can check the fan clutch with the engine shut off when the engine is cold you should be able to turn the fan by hand if it is thermo viscious. it could also have a air clutch which could be either air on or air to turn off try to determine which you have. you might also try the heavy duty forum at *************** (you can't type web addresses here)

[LMJD]

Longhood, you can type them. There's only one you can't and for good reason.

[379Longhood]

Originally Posted by LMJD

Longhood, you can type them. There's only one you can't and for good reason.

So can somebody enlighten me