External Oil Cooler Mount / Air Directional Flow Theory

[Splitdog]

I have a 2165 turbo motor with no thermostat, flaps, or velocity ring. Also not running any front, or rear tin. I was in LA, and oil temps were 200* going down the freeway. I removed the stock cooler, blocked it off, and welded up the hole in the rear of the fan shroud. I am running a 72 pass cooler up under the package tray. My oil temps dropped 10*. It's because I'm getting more air over the heads, where the heat is made. Then cooling the oil downstream later. If you run an aftermarket cooler and fan, you definitely gain by removing the stock cooler. My .02.
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CH³NO²

Z = z² + C

Der Blitzkrieg Kafers

#notacallooker

[richparker]

[mikedjames]

This is the cooler I have used for about 10 years.
Its only failure was that after a while the stainless steel sheet (ex Ikea bathroom cabinet) cracked and I was dragging one side along the road for a while. A quick zap with some stainless steel wire in the MIG welder and a few strips of fresh metal, it's back.

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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[Splitdog]

Next time the shroud is out ditch the stock cooler. Temps will drop.
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CH³NO²

Z = z² + C

Der Blitzkrieg Kafers

#notacallooker

[richparker]

The coolers run parallel. The oil enters a machined aluminum block, splits, 1/2 runs through each cooler and rejoins in the aluminum block before going to the filter and back to the case. My fan pushes air over the cooler. This set up is located on the drivers side of my engine bay. In this location the oil lines are short and everything is protected from the elements. After taking many readings with a IR gun and comparing them to my gauges, the oil is returning to the case 30° cooler then it left.

I also have a 180° Tstat and use a Wix 51515 filter, which is also in the engine bay.

2 case plugs were removed and were machined to accept the fittings. The oil comes out the lower line, returns in the upper line and goes through the factory oil cooler (I have a T4 cooler in place of the T1) before it goes to the bearings.

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’71 Westy build
Adventure thread
’65 Deluxe Build

[plywoodkid]

Rich,

That is slick….

Well done!

[SGKent]

that will work. Good job.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[richparker]

[Glenn]

^^^^^^
Dual Type 1 coolers?
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"

Member #1009

#BlueSquare

עַם יִשְׂרָאֵל חַי

[richparker]

My cooler has a custom shroud built around it.

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’71 Westy build
Adventure thread
’65 Deluxe Build

[SGKent]

Scott I like your design. I can see from the photo it is well thought out.

Sodbuster - am sure yours works well.

When a fan sits over a radiator / cooler, it must cover almost 100% or the air simply flows around the cooler and draws in from the side because of the more restrictive fins. Think of a hose - even a small hole in it results in a huge leak because it is easier for the fluid to go thru the hole than down the more restrictive path. I've seen racing engines overheat because of small gaps in the cooling shroud between the fan and radiator. If there is a gap on the side of the fan where it overhangs the radiator / cooler, find some sheet metal to block that area.

The top image will work because the fan will pull thru the fins. The bottom image will lose most of its cooling ability unless the section overhanging the fins is blocked off.

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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[plywoodkid]

[mikedjames]

When I fitted an external cooler, I decided that for a horizontal radiator the airflow should go up as that would be the natural passive flow. Then I fitted a forward facing scoop made out of thin stainless steel sheet.. if it gets caught or crushed it gives way.
This way no big cooling fan at all and one less thing to break.

Drops oil temps about 20F. Still use the doghouse cooler.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[plywoodkid]

Thanks for all the comments. Very helpful. This will definitely assist me as I adjust in the future whether that is remounting and ultimately probably purchasing a new cooler set-up.

Based on the discussion and advice, I’ll leave the configuration as “pulling” and give it some run time and watch the temps. My sender is close to where the oil leaves the case. I also have a 3.5 sump as well. I have about 200 miles on this new engine. Like Aeromech and others have stated, I may need the cooler less than I think. While breaking the engine in, I was purposely was in a lot of stop and go situations, so maybe I misjudged some of the temps.

Scott, I really liked that prototype.

[germansupplyscott]

We've been working on a complete oil cooler kit - to offer for sale - for a while. Two kits actually, one for Type 1 engine and one for Type 4 engine Buses. We use a Setrab fanpack and components - Setrab has a new line of billet filter mounts and sandwich plates with integrated thermostat, super nice stuff. The fan is a puller. The fanpack is very small but perfect capacity for the Bus engines. This kit has been installed in prototype form in 2 Buses and it works super well. Type 4 engines especially tend to run pretty hot oil temps and this setup keeps the oil at or below 185 all day long. There is a thermostatic switch for the fan and a simple shroud to direct air into the cooler. I think the ducting could be improved frankly, but it works.

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SL

[vwwestyman]

I recall when I was looking at fans for my Bus' radiator, that most are more efficient when pulling/sucking than when pushing/blowing. It seems like the average was somewhere around 20% difference, but that was some time back so I could be making that up in my head.

Unless it is just a crappy model, the fan's blades are designed to have hot air passing over them-so that shouldn't be a concern.

Concerns about debris and the like are valid, though!
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Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[sodbuster]

I have run that same set up for about 17 years with one difference. the cooler sits between the frame rails instead of outside them. It will tuck up a little more too. cooling and airflow has never been a problem. My sink drain and rear sway bar hang lower than the cooler I also run an inline oil thermostat as well.

Best you trust the folks that actually made your cooler. You seem to have good info there. I'm betting they put more thought into it than anyone. in other words. Try not to over think it too much.

[RalphWiggam]

Are you sure you even need a fan?

[plywoodkid]

Aeromech, you are correct Sir. Doghouse Cooler and External with Fan.

[aeromech]

So you actually have two coolers plus the fan, right? It is possible to have too much cooling. You want your oil temp to be 185-220 or so. If it runs cold you accumulate water in your oil. Going down the road there should be plenty of airflow over your #2 cooler. Now, if you plan to do stop and go in Los Angeles in the hot summer you might need the fan.
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