wolfe10 wrote:
Not sure I understand why you would have two different filters on a hydraulic system. This is particularly true if you have the large canister with a stack of 2-3 filters. That is a LOT of filter media with very little restriction due to surface area.
Out of curiosity, check the micron rating on the large canister, stacked filters vs the spin on unit.
Now, if you actually have two separate system, one for PS and one for the fans, the two filters make perfect sense.
Yes, my coach has the stack of filters in the canister reservoir. Will check micron ratings and call Monaco Tech Support to see if they can confirm I'm using the right filters.
randallb wrote:
Only one thing blows up filters and that is excessive pressure. Not having enough information to find the schematic for your system you will either have an inline pressure bypass valve or an internal bypass in the pump. One or the other is allowing the pressure to grow until the filter blows. It could be that someone has mickey moused the system to increase pressures because of a faulty fan drive or other issue with this portion of the cooling system. The stacked filters in the reservoir may be partially clogged restricting the intake to the pump and this was "corrected" by playing with the bypass, if it is external. Pull the pump, have it checked but be sure to tell them it occurs after an extended run. Otherwise they will run it for a few minutes and possibly pronounce it good to go. If it checks out ok start looking for wires disconnected, spliced together or other obvious signs that someone did not want to spend the money to fix a previous issue in a proper manner because of cost. This could easily be something as simple as a return line restrictor, normally installed near the reservoir for noise reduction or splash control, that has become partially blocked with age. Good luck with the repair. I hope you can do this yourself because it will get very expensive to have someone else do it.
Randy
So I know the spin-on filter is new as I've replaced it 5 times in the past year or so. I'll pull and change the filters in the canister too. Here's hoping it's that simple and cheap. :-)
My regular mechanic also suggested pulling and bench testing the pump but I will definitely let the shop know the pressure builds over 4 hours not 4 minutes! Good suggestion!
If I can get under and trace the hose route what would I look for in terms of an external bypass as opposed to a bypass built into the pump itself. Would it look like an inline check valve or would it be more of a T where it would divert extra pressurized fluid back to the reservoir?
Also, what might a "return line restrictor" look like? Would it be right at (or in?) the canister filter?
Thanks!
