Oil coolers 101

Hi all,

Looking for a little help with the layout of my oil cooler set up.

Basically, my car has an existing modest sized oil cooler run directly off a sandwich plate at the oil filter on the block. What I'd like to do is a) install a remote oil filter, and b) add a second (larger) oil cooler in series.

So, should the plumbing go like the following?

1. remote oil filter adapter on the block,
2. -10 (or maybe -12) supply/return lines to the remote oil filter from the block adapter,
3. sandwich plate on the remote filter with supply/return lines going to the two oil coolers in series.

Is there a different/better configuration than this?

Related questions:

1. Should I use -10 AN or -12 AN lines? -10 looks a little small in diameter to me for a SBF stroker.
2. If I incorporate a thermostat in the plumbing I presume that goes downstream of the sandwich plate at the remote filter mount, correct?
3. If I incorporate a thermostat in the plumbing what temp should the thermostat be? 195? 210? 225?

Thanks in advance for any help on this one.
Plumbing the coolers in series might increase the pressure drop.While I dont know the actual size of the coolers you have, perhaps the best option would be just use the larger cooler only. Remember every fitting and bend plus other stuff like adapters, thermostats also inhibit flow.... just another of those situations where less is more.
Yup, got it JacMac. Makes sense. The first/original cooler is fairly small. The one I want to add is pretty big......a Modine which is 11" by 11" by 3"

I'm trying to minimize the drag in the system.....no 90 bends. -12 AN lines, etc. I'll add a few pics so it's easier to visualize.

Consider the Setrab ProLine engine oil coolers. Sometimes you just need a little help and an auxiliary oil cooler is all you need not a full size. The link posted here shows the pressure drop (20-50 oil) of the cooler so factor a little more for your fittings and bends.

Mine made a huge difference with the ram air duct and fan pack. Thermostat kicks the fan on hot days.


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Howard Jones

Looking at the picture of Toms car I would say do it like his. Good part selection. You only need one cooler. Two in series is a box of monkeys. Twice as many fittings etc, just asking for leaks. IMHO
Here is how I plumbed mine. I used 10 AN lines as that is the size the filter adapter, remote filter, and coler required. I also have the Accusump setup as well. The remote filter setup has 4 ports, two in and two out. My cooler utilizes a thermostatically controlled fan and that uses all the ports as outlined in the pic below. Lines are:
oil into the filter and out to the thermostat below. The other ports are for the thermostat controlled fan, and out line to the oil pressure gauge. The line to the oil pressure gauge is also a safety setup. It has a switch that if the oil pressure drops below 20 pounds it activates the Accusump to pump in 3 quarts of oil to the system. If for any reason this does not bring the oil pressure back up it immediately shuts down the fuel pumps(I am thinking of changing this to shut down the electronics to the engine, as I have noticed on shut down that the pumps continue to pump for a few seconds before shutting down). My wiring is such that without oil pressure the pumps cannot be turned on, so a bypass switch is on my dash that bypasses the low oil pressure cutout, allowing the pumps to run before I hit the starter. This is of benefit in that I can spin the starter without the pumps being on(for tuning etc.), and it keeps air from being pumped by the high pressure pump. It also means I can prime the engine with oil before startup if it has been sitting for an extended period of time. Once started the oil is pumped back into the Accusump(the sump plunger is charged with air to 60 lbs.).
The thermostat below the filter is a partial setup and allows a small flow of oil to the cooler as it warms up so there is no surge of cold oil to the engine. Once hot, it is open. There is a one way valve on the return line to the engine and the Accusump line is plumbed between the one way valve and the block. This allows the oil pumped from the Accusump to go only to the engine and not backward to the cooler.
Hope this is clear.

I've got a Setrab radiator which is a little bit overkill.. but in combination of a bypass thermostat. see explanation (Mocal OT2). It lets the oil bypass the oil cooler and closes bypass when hot to let the oil go through the cooler. I'm using AN 12 lines, no bends and the bypass thermostat starts at 82°c.
Also a manual fan is installed + air ducting. Without air duct there is not much benefit at low speeds.
Also not forget to always run the hot oil to the bottom of an oil cooler.:shocked:


Thank you gents (Tom, Howard, Bill and Curt), this is really helpful - picking up lot of tips and insights here. My fear is that through some dumb design/engineering mistake of mine (not much of a stretch for me......) I starve the engine of oil and burn it up.

Just a bit of context: it's a 347 stroker going in a Lotus Esprit which previously had a 2.2 liter engine.....so some serious cooling upgrades are necessary.... I'd like the water and oil cooling to be as effective as possible.

Let me mock this up on the garage floor and attach a few pics - again, really appreciate the input. Thanks