blau928

Does anyone know which oil line from the block is out to cooler, and which is in from the cooler..?

I am speaking about the oil fittings on the block that plumb to the cooler lines in the radiator..

There are two fittings, in a vertical arrangement. Is the upper or lower out from block...?

Thanks,

ammonman

IIRC the lower block connection is supply to the cooler (Oil out of engine) and the upper block connection is return from the cooler (Oil in to engine).

Mike

blau928

thanks...!

mark kibort

so the oil has to pump up through the cooler? then, where does it go, to the engine bearings and up to the heads or does it hit the filter first??? mk

Rob Edwards

I bring nothing to this discussion other than two diagrams from the 1978 service info tech manual, which I cannot grok, other than the lower hose (K) is the feed to the oil cooler and the upper hose (r) is the return.

Can anyone draw red and blue arrows on these illustrating hot and cold operation?

mark kibort

so why did the open oil lines, pump oil out onto the floor of my garage, if the there is no oil flow when cold?

also, I wonder how the water went from the lower cooler line into the oil pan. did it have to fill the internal passages until it was the same level as the pump output, or is there another passage. there was no water in my oil filter, so some path must have been a little lower for the water to go to the pan.

SharkSkin

When cold, the oil cooler is pressurized at whatever pressure the pump is outputting, up to the 8 bar cracking point of the "Pressure Relief Valve", #3 in the first diagram. There is no flow because both sides of the cooler see the same pressure. The diagram below shows the system in this state:



When hot, the shuttle valve rises and blocks the top outlet port in the t-stat housing, forcing all oil to flow through the cooler. Red is oil from the pump, blue is oil returning from the cooler:



If the pressure drop across the cooler exceeds 0.5-1.0 bar the relief valve (4) opens to allow full flow. This permits full oil flow/pressure in the event the cooler is clogged, lines kinked, etc.

SharkSkin

See the first two sentences in my previous post. There is ALWAYS a wide-open path between the cooler and pump. There is also the potential for water to get into the oil filter and fill that up, so keep a close eye on the oil, watching for any signs of milkshake.

It probably just trickled back through the pump. The pump does not provide a perfect seal, just "good enough" when running. Spec calls for axial play in the pump of 0.08 to 0.12 mm, more than enough of a gap for water to seep through.

SharkSkin

So Rob... did that answer your question?

Rob Edwards

Dave-

Yep, thanks 1x10^6, sorry I didn't respond sooner! It's one of those things that I spent a lot of time staring at both the diagram in the book and at a naked engine block and girdle, spinning my finger clockwise in the air in front of the oil pump housing, trying to visualize the oil flow and failing to do so. Kind of analogous to how I read wiring diagrams- Poorly. I just sort of assumed the thermostat was blocking flow to the oil cooler until the oil warmed up, not that it was blocking the bypass AFTER it warmed up.

6.0-928S

Generally speaking with coolers, since heat rises, the hot (incoming) line is at the top & the cooler (outgoing) line is at the bottom. Otherwise the oil would follow the path of rising heat which would be counter productive.

Hammer

SharkSkin

Yep, it actually makes more sense this way, since the method you describe would involve opening a port to the cooler and closing the bypass at the same time.

SharkSkin

Leaving aside for the moment that the oil flow is probably more than enough to overcome convection, the flow on the oil cooler does in fact seem to flow from bottom to top.