740 & 760 230 Oil Sender and Oil cooler

Hey guys, just a few of questions regarding oil supply for red blocks.

Easiest question first: where is the oil pressure sender in regards to flow - is it before or after the oil filter?

The stock air oil cooler mounts long ways vertically - one fitting at the top and the other at the bottom. So after cool down when the thermostat is opening, does that mean majority of the oil drains out of the cooler back to the sump?

It seems to me that way. Thus every cold start the pump needs to fill the cooler and lines? What does this do to supply delay for start up? Furthermore, I assume in the oem sandwich plate the thermostat in its open position does not block of either direction, ie flow is allowed to the filter or cooler. If this is so, wouldn't majority of the oil go in the direction with least resistance - the empty cooler and lines?

It all works fine obviously... But I'm trying to add in a relocation and cooler setup so these questions are coming to mind. The best orientation I'm finding to mount my cooler is the same as stock, but according to 'correct' cooler orientation, the stock setup is a big no no. I've considered including an anti-drain back valve but I think that's a little convoluted and would add a small restriction...


  • The oem thermostat does not open until oil exceeding a set temperature is passing through the sandwich plate

    This way no oil passes through the cooler until the engine is hot

    Also the thermostat is variable (not on or off) so you should never see the oil pressure drop

  • Ok I just found a diagram by Dave barton showing the oem thermostat. The greddy thermostat I have is different. It doesn't block of either passage rather sits in the middle and lets oil go both directions when cold. When hot then it shuts of the passage to force oil to the cooler.

    I guess my question I'm trying to ask is Is there enough delay of oil pressure if the pump were to fill a cooler (with similar capacity to stock cooler) during every start to cause worry? If not, then don't bother reading the rest of this post...

    This is the greddy setup I have.

    Oil goes from engine into oil filter, then goes either to cooler or back to engine. So lets say engine is shut off: Any oil cannot escape rearwards because of the one way valve in the filter. But it is free to drain forward through the oil system in the engine, can oil with viscosity at hot temperature move through the engine under the effects of gravity over a period of time?

    Look I feel like I'm possibly inventing a problem that does not exist, but my worry is that there is possibly lots of volume the pump needs to fill up before the engine would see oil at every cold start for my setup.

    Is the pressure sender post filter?

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