seuadr 489 #1 Posted March 23, 2021 Hi, Working on remote oil filter for my onan: Couple questions: Is that a pressure switch or transducer maybe? That plug on the opposite end faces down - is it maybe a drain? Share this post Link to post Share on other sites
JoeM 8,334 #2 Posted March 23, 2021 sure looks like a pressure switch. Could that port be a built in relief? Take the fitting out and see I suppose. Share this post Link to post Share on other sites
seuadr 489 #3 Posted March 23, 2021 (edited) Just a passage under the bolt - when mounted it points down. But i did find this: It suggests that there should be a bypass in there. Wonder if i am missing parts? Edited March 23, 2021 by seuadr Share this post Link to post Share on other sites
JoeM 8,334 #4 Posted March 24, 2021 7 hours ago, seuadr said: Wonder if i am missing parts According to the Duke's drawing there is supposed to be a spring, and valve under the plug. I would say without it the filter won't be doing much. Looking at the backside under the gasket the ports look like this one. Share this post Link to post Share on other sites
seuadr 489 #5 Posted March 24, 2021 Yep. Guess I'm going to have to try and locate replacements. Share this post Link to post Share on other sites
seuadr 489 #6 Posted March 24, 2021 Turns out i do have them! The hole was so gunky i could not tell. Oh well, already ordered replacements. On the bright side it sounds like in general you should replace the spring whdn rebuilding so that was obviously the plan all along. 😁 Share this post Link to post Share on other sites
seuadr 489 #7 Posted March 25, 2021 (edited) Well i went to the hardware store today and the fittings that go into the block are 1/4 npt, but, the other side, which i assumed was a 45 deg flare is.. something else. the threads that fit are compression but of course, compression doesn't fit because of the flare on the end. thinking rather than getting complicated trying to adapt them i'll probably just go barb fittings. the question becomes - what size oil line is appropriate? the biggest i can get would seem to be the logical choice, but bigger isn't always better. i'd guess the lines that are on there are about 3/8ths ID and i should be able to get 3/8ths hose pretty easily. 3/8th i.d. "transmission hose" is braided and looks like it is good for 300 deg f - i'm guessing that is more than sufficient for oil? thoughts? thinking about how to split off that brass fitting for the sending unit to get a combo oil pressure/temp sender for a gauge.. Edited March 25, 2021 by seuadr Share this post Link to post Share on other sites