Logo
FULL SITE MENU

low oil pressure problem

S

sebcaptchris

New member
Bought a boat with two gen vi 454s one has great oil pressure the other good but after running to temp drops to extremely low oil pressure. previous mechanic said it happened to him on two other motors he installed in same boat and gave up. what is he missing/ claims he rebuilt one himself and replaced one from rebuilder. Any ideas??
 
Ayuh,... Exactly What are you callin' Good oil pressure,..??

'n What, exactly are ya callin' extremely low oil pressure,..??
 
bondo said:
Ayuh,... Exactly What are you callin' Good oil pressure,..??

'n What, exactly are ya callin' extremely low oil pressure,..??
Click to expand...

40 lb at 3500 rpm and close to 5 lb at idle after warm, have read a lot about bypass valve needing to be at 30lb with oil cooler and remote oil filters , the troubling part is two identical motors two way different pressures , any thoughts are greatly appreciated!!
 
What by-pass are you mentioning?
The GM oil filter base adapter does have a by-pass arrangement, but this is only operational during filter media saturation.
It will have no bearing on what oil pressure the oil galleys see!
Oil pressure is controlled by the oil pump's pressure relief valve!
Excessive clearances may cause an issue, but you'd likely see other issues as well, if that was the case!

Since you have twins, try swapping pressure senders and/or gauges.



.
 
I have the same problem on 1993 5.7 Mercs. Switched oil pressure senders, and finally used a mechanical gauge. Pressure starts out ok, then drops very low (5 or maybe less) at idle, but kicks up again at high RPM.
 
Back
Top