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M38 Oil Pressure Gauge / Sender

Posted: Mon Aug 27, 2018 2:55 pm
by SCJeep
I'm confused...what is the correct configuration for a 1952 M38? 60 psi oil pressure gauge or 120 psi oil pressure gauge?

Currently in my Jeep I have a 60 psi gauge but I think I must have a 120 psi sender because my pressures are low. When I broke the engine in I ran it with a mechanical gauge and all was good. I think I must have ordered the wrong gauge and/or sender 15 years ago when I purchased all my parts for rebuild. I'm trying to get it back to "correct". I like the resolution of the 60 psi gauge. So should I get a new gauge or a new sender to make my system compliant?

Posted: Mon Aug 27, 2018 3:27 pm
by wesk
The M38 came with a 120PSI Gauge & sender. Yes they need to be matched, The M38 ORD 9 SNL G-740 lists each of them. The Army eventually converted most of the M series fleet to 60 PSI for the same reason you like it.

In my photo album under TB's & MWO's I have a copy of the pub they used for the swap.
http://www.willysmjeeps.com/v2/modules. ... _album.php

You should be using TB 9-2300-228-20 for troubleshooting procedures and test values on the M series instruments. You can download a copy free on our downloads page.

60 PSI Gauge: PN's Autolite EO-11932, AC 1907975, Stewart Warner 505L,

60 PSI Sender: PN's Autolite EOF11993, AC 1507980

Posted: Wed Aug 29, 2018 9:00 am
by SCJeep
Thanks for the guidance. I confirmed that the sender on my Jeep is a 120 psi. I just ordered a 0-60 psi sender to make my gauge work properly.