I have a 95 HP 500C that is ungergoing a full rebuild/upgrade. As part of this, I'm going to switch from the stock oil filter mounting block to the merc unit that was on the 525 with the thermostat.

The stock hp500 has two pressure relief valves pressed in to the block oil filter mounting pad (item 12 on pic one), one on the center (which will not be replaced) and one to the side. The new filter block/thermostat also calls for the pressure relief valve (item 22 in pic 2).

Which one (or both) should be installed? I've already purchased the 30psi valve vs. the stock 11 psi.

Would it hurt things to use two, one in the engine bock and one in the thermostat block?





Thanks for any info

Ryan

i remove the one in the thermostat block[item22] and install the 30 lb bypass in the block,it has worked for me.

Mike

Thanks. Do I need to install a block off in the thermostat housing, or leave the hole open?

Ryan

you block the hole,i should have mentioned that.i use a welsh plug but i don,t remember the size.i have a bag of them in the shop and i will check it later.