Short of actually putting it on the car, how does one test an oil cooler to see if leaks? I have a few I want to sell but I want to know if they leak or not first.

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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Se if they can't help you.

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'84 300SD sold
124.128

Assuming they have already been cleaned inside you could pressurize them with 100 psi of air and submerge them in water and look for bubbles.
You would need 2 modify 2 old oil cooler hose fittings. One to accept the air line connector and the other to act as a plug.
It would be best if the Air Compressor had a Regulator to adjust the pressure down to 100 psi.

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84 300D, 82 Volvo 244Gl Diesel

Thanks for the tips.

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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

be careful if you use compressed air......if the oil cooler is weak you could hear a loud noise and have some shrapnel flying around your shop.....

it's much better / safer to use a hydrostatic type test.......liquids are not compressible, thus if there is a crack or weakness it will not explode, the liquid leaks out and pressure drops off instantaneously......

you could use an old hydraulic jack...or even a FI Pop Tester pump.....and pipe it up with a pressure gage and a valve (pressure gage between cooler and valve) on one end and plug the other.....pump it up to 1.5 x working pressure......3++Bar is most likely somewhere between 45 and 60 psi.... so you would want to test between 65 and 90 psi......pressurize the cooler and shut the valve......wait awhile and see if the pressure drops off.....if the pressure remains stable for a half hour or so....you're good.....!!

SB

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

I would take it to a radiator shop and have them test it. If it leaks, have them fix it.

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2013 Jeep Unlimited Rubicon
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SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL

A quick check if your household water has about 60 lbs pressure. Put a hose on the one fitting. Since you probably have an old oil cooler hose use it and close it off either by folding over the hose and using a clamp. Or installing a plug and clamp after cutting the hose. . The use of the old oil cooler lines allows you to quickly change from one oil cooler test to the next one.

Take another old oil cooler hose and cut it. Install a fitting to hook up to a garden hose in the cut end. This will allow a test up to your available water pressure. It is better of course to take it higher to say a hundred pound test but probably good enough to spot a bad oil cooler. If the cooler drips it's an ebay item.

Thanks for the ideas! My local radiator shop refuses to work on oil coolers because they say that they would "melt in their hands".

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Stop paying for animal enslavement, cruelty, and slaughter. Save your health and the planet. Go vegan! I did 18 years ago. https://challenge22.com/

DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

When my car idles and the oil is cold I get 89 psi. The Oil Cooler should easily handle 100 psi of air pressure. Your Oil pressure gauge only goes to 3 bar but you have more oil pressure than that.

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84 300D, 82 Volvo 244Gl Diesel

3 BAR converts to 43.51131 psi = (lbs/sq.in)

You should not need to test at a higher pressure.

Air molecule density is lower than oil molecule's = it leaks easier in a water test tank given any escape path (crack)..

http://www.grc.nasa.gov/WWW/K-12/airplane/fluden.html

http://en.wikipedia.org/wiki/Density_of_air

http://academics.vmi.edu/chem_jt/CH131/density.htm

http://www.stevespanglerscience.com/experiment/seven-layer-density-column










Have a great day.

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1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

If it leaks out easier that would make the test with air even more conclusive.
ForcedInjuction had told me that the oil pressure was over 100psi (I do not remember the exact figure but it is about the amount the the Oil Pump Relief Valve opens at) but I did not believe that.
When I was looking for a place to tap in my Bypass Oil Filter system I drilled and tapped 2 holes through the top of my oil filter cap.
I installed a test pressure gauge and with a cold Engine my pressure was around 89 psi at idle. If I revved the Engine hot or cold the pressure went up to 97 psi but no higher.
That 3 bar pressure gauge dose not reflect your maximum pressure at all.
It is easy to check for yourself.
Remove your Oil Filter Cap/Top and look inside to see where the casting webs are. Pick a spot where you do not drill through a web and drill and tap it for 1/8" pip plug; hook up your test up there gauge.

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84 300D, 82 Volvo 244Gl Diesel

That is why I quit posting here......nitpicking.....if you read my pose closely, you will notice that there are 2 each plus signs behind the 3.....you also could have noticed that 60 psi is approximately 4 Bar.....I haven't a clue as to how much oil pressure my car actually runs at....but 3++ Bar describes it kinda well.......

The point was .....
Rule of thumb.....most pressure vessels are regularly tested at 1.5 times the working pressure of the vessel.....
Your oil coolers are old, no need to over-pressurize them.....
I didn't want anyone to get hurt with compressed air......
I also didn't mention house water because I didn't want to contaminate the interior of the cooler with water.......

AND....I have never seen any MB data on what the oil pressure actually is, just that.......

"At operating temperature, oil pressure at idling speed may drop to 0.3 Bar gage pressure. Upon acceleration oil pressure should rise again immediately and attain at least 3 Bar gage pressure at 3000 /min"

SB

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Sorry, I was not trying to argue with Hunter.
No matter what people say in the Forum it is always the judgement of the reader that matters.
I found the Pic I took when I tested.

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84 300D, 82 Volvo 244Gl Diesel