Hissing, no leaking

daTeacha · Feb 1, 2007

On my DX29 hst, a short while after start-up, say 10 to 15 seconds, there is a pronounced hissing noise that seems to be coming from the vicinity of the hydro pump in the right front. Everything works, nothing leaks, and the noise goes away after a few minutes. This is not a new thing, but has been going on for a couple of months. It doesn't seem to be a problem of any kind, but seems louder in cold temperatures. Anyone know what it is? TRactor has 115 hours on it.

RickB · Feb 1, 2007

Minor cavitation caused by the pump trying to drag cold, thick oil through the main hydraulic(suction) filter.

daTeacha · Feb 1, 2007

Thanks. Is there any potential for damage to the pump? Any way to prevent it except changing out the oil?

DieselPower · Feb 1, 2007

Are you letting the tractor warm up a little on cold day's before using it?

If it's really cold where you are you might consider using a winter UTF, it's a little thiner.

RickB · Feb 1, 2007

If you let it warm up at or near low idle to minimize oil flow during warmup the damage potential is low. A heated building or low viscosity oil will make the symptoms go away for the most part. Pretty much a normal deal for any tractor with a fixed displacement pump and a suction filter; whether anyone actually hears it or not. That covers about 90% of tractors built in the last 50 years. It is not something that keeps me awake at night.

daTeacha · Feb 1, 2007

Yeah, it runs a bit before I even lift the bucket and/or counter weight. It hasn't been seriously cold -- lowest has been about 6 or 7 F. It's been around 15 or 20 when I start the tractor.

DieselPower · Feb 1, 2007

6-7 degrees F. is starting to get rather cold. You may need to let it warm up a little longer or as I suggested go with a winter UTF fluid. Winter UTF fluids are fine for use in the summer as well. Most regular UTF fluids are about 10W/20 viscosity while winter UTF's are the low side of 5W/20 and also have a better viscosity index.

jbrumberg · Feb 1, 2007

DieselPower said:
6-7 degrees F. is starting to get rather cold. You may need to let it warm up a little longer or as I suggested go with a winter UTF fluid. Winter UTF fluids are fine for use in the summer as well. Most regular UTF fluids are about 10W/20 viscosity while winter UTF's are the low side of 5W/20 and also have a better viscosity index.

DieselPower:

You seem to know your "stuff". I checked your profile and now I know that you know your "stuff"

! Thank you for the information

! Jay

daTeacha · Feb 2, 2007

Okay, time for the dumb question -- If the 5W/20 fluid works well in summer, why would CNH even bother with the 10W/20? It would seem they would do their reputation a better service if the tractors were shipped ready for whatever climatic conditions they might encounter within a given region.