Thermostatic oil coolers and pressure drop

[russtik]

Top and top Matt

[Matth93]

Oh ok can’t see it making any difference then

[steve m]

When I had a cooler on my car, I had the input and output of the oil cooler rad pointing up, as in my uneducated view, it meant that I always had oil in the rad, cold or hot, and that also meant that the sump /dipstick held an extra 500 ml (ish) to aid in cooling

I never had a oil stat, just straight through pipework

steve

[russtik]

Well I’m a bit stumped... I’ve taken the hoses off the sandwich plate and can successfully blow oil through the system (in the direction it was flowing). The route to the cooler is open at all times and the thermostat closes a bypass at 80 degrees forcing the oil to take the route around the cooler and back. That’s when the pressure drops off so I suppose it’s insufficient rate of flow under pressure??? But where’s the restriction? I can’t get to the bare hose but the end fittings have an ID of 10mm.

[steve m]

Compared to the setup I had, with the oil cooler behind the rad, and both hoses were only about 300mm long

Yours look to be a good metre each, and wonder if they are the reason the pressure drops once the temp gets hot, and the valve allows the oil to flow to and from the oil cooler,

steve

[DJ.]

Sorry I can't add more to the deliberations, but I have to say that is a very nice engine bay

[Tony C]

The oil cooler hoses on the Sprite were long, probably close to a metre, never had any pressure problems. Could there be air in the hoses/cooler that causes the pressure drop when the oil is diverted that way. Would have thought the pump had enough oomph, nothing special re oil pump in the Sprite.

[David T]

Pipes have internal damage or manufacturing fault? Same for cooler matrix?

[Tony T]

It sounds like a pressure release valve problem mate its plying up they can stick some times and then go back till the next time

Tony T

[russtik]

Well I’ve tracked it down... I bypassed the cooler with an end-to-end coupler. Lo and behold when the oil is hot and the thermostat closes the pressure remains absolutely fine. So it’s the cooler rad that’s causing the restriction in flow. This is disappointing because it’s a brand new Mocal one At least I know the root of it now though.