Ridal Posted July 18, 2014 Share Posted July 18, 2014 Toyota 5K. I have shimmed the oil pump pressure release valve and all was good, running 1/2 on the standard gauge at max pressure. When cold it would be on max at low rpm as determined by pressure release and come down as oil temp increased as you would expect. Recently it would start low when cold and slowly work its way up to max pressure as the oil warmed up. More recently it has not reached max pressure and only increases slightly with rpm. I hooked up a mechanical gauge to see what was going on and it was 30-40 psi (low-high). Turned engine off. Started engine 15 mins later and quickly went up to ~70 psi which is what I would expect the release valve value to be. Now it is back to 30-40 psi. I just changed the oil and filter using a genuine filter and engine flush which has made no difference. I'm thinking a blockage somewhere but I'm not sure. Any ideas? Quote Link to comment Share on other sites More sharing options...
peteretep Posted July 18, 2014 Share Posted July 18, 2014 why did you need to mess with the pressure relief valve in the first place? that is the first place I would be looking anyway Quote Link to comment Share on other sites More sharing options...
Ridal Posted July 18, 2014 Author Share Posted July 18, 2014 To increase pressure. It's just a matter of putting a 3mm washer at one end of the spring to increase the spring force. I think it's unlikely the cause because if it was jammed shut pressure would be high and if it was fully open pressure should still reach high pressure at high rpm and be super low at low rpm. Quote Link to comment Share on other sites More sharing options...
Spencer Posted July 18, 2014 Share Posted July 18, 2014 Just take it out and see what happens, the oiling system on these is bullet proof. I doubt you needed extra pressure anyway? What grade oil do you use? Quote Link to comment Share on other sites More sharing options...
kurtis1791 Posted July 18, 2014 Share Posted July 18, 2014 30-40 psi should be fine. My commy when cold has max of 50 and drops down to about 8 when hot at idle.All within spec Quote Link to comment Share on other sites More sharing options...
ajg193 Posted July 18, 2014 Share Posted July 18, 2014 As long as the warning light is off and there is oil in the motor you should be fine. High pressure => blown seals Quote Link to comment Share on other sites More sharing options...
Spencer Posted July 18, 2014 Share Posted July 18, 2014 A relief valve set at 70psi isn't going to blow seals, how many "seals" does the oiling system in old stz actually touch on the pressure side? It passes some gaskets and then some holes into bearings/crank/cam/rocker gear, nothing that will blow. If this thing has 30-40psi at idle hot it obviously has a good condition bottom end and oiling system or is running too thick oil. Remove relief shim and see what's up? Quote Link to comment Share on other sites More sharing options...
Ridal Posted July 18, 2014 Author Share Posted July 18, 2014 Running 10W/40 semi synthetic. The thing that's troubling me is that in the space of two start ups in a short period of time it went from low to normal to low. Quote Link to comment Share on other sites More sharing options...
Jase Posted July 20, 2014 Share Posted July 20, 2014 its not over full? as that'll froth the oil up and drop pressure as the pump picks up air laden oil. Quote Link to comment Share on other sites More sharing options...
downtrail Posted July 20, 2014 Share Posted July 20, 2014 We go by you should be able to make 10psi of oil pressure per 1000 rpm if its making that fine i wouldn't worry Quote Link to comment Share on other sites More sharing options...
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