I have a B7100HST that lets out a very loud pressure release sound every now and then. It sounds like someone taking an air hose off an air compressor. What could this be? I have been looking and looking and cannot figure out what causes it. It will even do it sometimes about 10 or 20 seconds after I shut the tractor off. It almost has to be something in the hydro's that is making this noise. Is there a release valve somewhere or something? The fluid level looks good, so I don't know.
B7100HST Loud Pressure Release Sound
- Thread starter evan4434
- Start date
I'd look to the cooling system. The hydraulic pressure relief has a distinctive screech to it, not much like an air hose. Steam blowing out though, much like an air hose. At least try a radiator flush and refill with distilled water/antifreeze at 50/50 mix.
I checked the antifreeze and it was about 1/3 gallon low, so I filled it up to the top while cold. I ran it for about 15 min and the overflow was dripping pretty good on my garage floor when I got back. What is the proper way to make sure the right level is in? It would be nice is this thing had a temp gauge. It definitely is cooling related because it did not make and loud pressure release sound this time.
Thank you
Thank you
These are a thermo-siphon type cooling system. They are a little fussier than a normal system. These do not have water pumps so if water isn't high enough it does not complete the flow path and they boil sometimes.
So, as a start; use a jar of acid flush for cooling systems, rinse thoroughly, drain and refill with 50/50 mix of distilled water and antifreeze.
Maintain about halfway between the top of the tubes in the radiator core and the bottom of the filler neck. That allows room for expansion without coolant loss, top off only with distilled water. Distilled water prevents mineral build up in the radiator core, which cost $$$ to have boiled and rodded out.
Also there is a "seed-screen" (or should be) in front of the radiator. This needs checked, cleaned before starting every time. An occasional blast with cold water through the radiator on a COLD engine, from the bad side is good practice.
If after this is still hisses the radiator may yet need boiled/rodded out.
(yeah, it looks like a water-pump, that's your dynamo)
So, as a start; use a jar of acid flush for cooling systems, rinse thoroughly, drain and refill with 50/50 mix of distilled water and antifreeze.
Maintain about halfway between the top of the tubes in the radiator core and the bottom of the filler neck. That allows room for expansion without coolant loss, top off only with distilled water. Distilled water prevents mineral build up in the radiator core, which cost $$$ to have boiled and rodded out.
Also there is a "seed-screen" (or should be) in front of the radiator. This needs checked, cleaned before starting every time. An occasional blast with cold water through the radiator on a COLD engine, from the bad side is good practice.
If after this is still hisses the radiator may yet need boiled/rodded out.
(yeah, it looks like a water-pump, that's your dynamo)
wow thank you so much. I did not now there was no pump. The antifreeze I put in was a premixed bottle that was already mixed 50/50. The inside of the of the radiator looked really clean, but I will check on a flush product and get that done before winter. I do clean that screen out often.
One additional note:
When your system is low, top it off only with a mix of 50-50 ANTIFREEZE and DISTILLED water.
If you add only distilled water you will over time find yourself with a system that is not freeze-protected.
You'd be surprised how fast you can on these small-volume thermosiphon cooling systems dilute the mix too much.
Keep a labeled jug of premixed onhand for just this purpose and you can gauge over time how much you're adding due to boil-off.
When your system is low, top it off only with a mix of 50-50 ANTIFREEZE and DISTILLED water.
If you add only distilled water you will over time find yourself with a system that is not freeze-protected.
You'd be surprised how fast you can on these small-volume thermosiphon cooling systems dilute the mix too much.
Keep a labeled jug of premixed onhand for just this purpose and you can gauge over time how much you're adding due to boil-off.
I toped it off the other night with the premixed 50-50, and no more noise still runs like a champ.