jahummer, thinking outside the box here. Could you remove the oil cooler and then block the ports with say some rubber tubing and then using a pressure regulator, apply say 40 or 50 psig air to the cooler itself. You can then use a soapy water solution and spray it over the outside. That would then bubble, showing you where the air is leaking from. We use this concept for finding leaking at the power plant I work at.

 

I don't think that approach makes sense for this situation.

The cooling system that feeds the oil cooler can only go up to 30psi before the radiator cap blows. It's currently leaking within the 0-30psi limit. Testing to 50psi is not only unnecessary, it could damage the cooler.

And it will be a ton more work to remove the oil cooler and create a test rig to pressure test it outside the car. It would be so much easier for the OP just to buy a quality coolant system pressure tester that can handle a rather paltry 30psi. Plus, the leak may still be in the oil cooler gasket, so by removing the oil cooler, he won't be be able to test the gasket at the full 30psi.

 

@Thermo I’ve done something similar. With the oil cooler removed, I blocked the coolant hole and applied low pressure to the pipe and it held without leaking. I was merely checking for any obvious easy to find leak and found nothing. By no means was that thorough but do know the coolant leak’s coming from the underside of the solid block of aluminum which really narrows it down to either the new gasket’s not working any better than the old one (which’s hard to believe - but would match the amount of coolant leaking), the pipe’s leaking at the point it enters the cooler (also hard to believe since it didn’t leak in the above test - metal’s rigid so it should leak regardless of PSI though temperature could be a factor, my test was ambient not engine temp) or the tube is leaking on the undeside where it connects to the cooler pipe.

 

Have you had problems with aftermarket ones? I purchased 6 new ones from
JLR and multiple aftermarket ones. Most of the aftermarket ones appeared identical in shape and hardness and measurement. A couple of the aftermarket ones did not.

I have used both with no issues so far.

 

A member brought me his car for me to trouble shoot his leak, he says he put a new water pump and new o,rings, 3 months ago (from parts.com) so I took it apart and found the O,ring for the water pump split ,then I asked did you put lube on it ,he replied yes ,so I put some of my JLR O,rings on ,then pressure checked it and ,that did the trick, I've done alot of these and see alot of mistakes, but I can't blame anyone, we all have to learn some how ,On the F-type the the oil cooler gasket disintegrated around the holes, that's why when I do a oil cooler I always put black gasket maker around the weak spots

 

Picked up a Snap-On pressure tester. Pumped it up to 18psi, all hoses rock hard and found coolant spraying from multiple locations and squealing/howling, including new hoses on throttle body and thermostat, new thermostat, etc. I've never observed this ever at full operating temp. I've had techs tell me before to stay around 15psi anything more and you're asking for trouble. Now I'm thinking they may have been correct.

Also should note coolant gushing all over front of engine. With TB out of the way, used inspection mirrors and could not find anything leaking, just some coolant pooling around the cooler tube but not spraying. Then I looked under water pump pulley and saw the coolant gushing.

So it appears I have spent nearly two weeks, a lot of labor and parts not needed when it was simply a 15 minute water pump repair.......

 

Crazy thing's the water pump was the first thing I removed, checked and replaced seals and gaskets. New pump now pump #4. First pump replaced by main dealer in warranty, no idea what failed. Pump #2 I replaced last year for the same reason I replaced the pump today, coolant spraying inside backside of pump pulley and shooting into the valley (and everywhere else and explains why the entire engine compartment was drenched). Only last year the pressure tester revealed what it did today except the one I was using was rubbish and the new one purchased today found the leak immediately.

At least the problem's solved, and there's new seals from the oil cooler up.

 

Cool everything good

 

The radiator cap is the equivalent of a fuse in an electrical circuit. Does it make sense to you that the weak point turns out to be the hoses and other plumbing parts? That would be like putting a 30amp fuse on wires and components that can only handle 15amps before they go up in flames.

If the system can't take more than 15 lbs of pressure, then cap should be 15psi, not 30psi.

 

The cap on mine opens at 26 psi. Regardless, I don't believe the operating pressure exceeds 15psi everywhere, if it did, there'd be leaks everywhere. The only hose that gets extremely hard when running at interstate speeds for an hour is the upper radiator hose, the rest stay pliable. Using the test at 18 PSI, all of the hoses got hard. Proof, the three new hoses that leaked at 18 PSI were not leaking for the past year since fitted and after the latest test drive to test the new water pump, they didn't leak either, they only leaked and whistled with the pressure test at 18PSI.

 

Well, I am glad my suggestion to pump to a higher pressure still solved your problem even though you fought me the whole way and even afterwards.

 

The issue was the tool I’ve used succesfully for the last 5 years. It’s the power built kit with plastic attachments and really intended for lower pressure systems. The SnapOn one goes to 35 PSI and is made of metal.

 

Then I am glad my suggestion got you to buy a quality pressure tester to test at a higher pressure even though you’ll never ever admit I was right for the rest of your life because you know better than anyone else in the whole world with all your experience.

People are funny.

 

I accurately articulated exactly what was going on and what was observed. It's impossible to diagnose faults through forums, which's why my first and only question was specific in asking for any members' experiences with oil cooler leaks. But don't take that to mean I don't appreciate other input or feedback.

This's the 5th time the super charger's been off in the last 5 years and I've replaced all of the hoses and pipes at least once (some more), expansion tanks multiple times, seals and gaskets, radiator, thermostat, both pumps, etc. The power built kit https://shop.advanceautoparts.com/p/...940427/9150049 has worked and helped frequently in finding elusive leaks on this one and others. Not sure why it failed me this time. As I mentioned in the initial post, I'd already done diagnosis and trouble shooting and serviced the water pump. I mentioned I pressurised the oil cooler out of the vehicle, replaced the cooler gasket, checked the aluminum pipes and everything else for leaks so I had to step back and rethink this as it was pretty certain everything was leak free. With your insistence on increased PSI and a conversation I had with a main dealer tech who suggested the Snap-On kit, the source of the leak took minutes to find.

I will add this, it did take higher PSI before the pump started leaking. Getting up to 15 PSI first time around and this time and nothing. Going to 18 PSI and voila!

 

Following up on this for future readers. Spoke with master tech at JLR and he confirmed I was indeed correct. They use the same Snap-On pressure tester I use.

He said leaks are detected at 15psi, as I have always done. Going to 18 or 20psi, it's not unusual for fittings to leak even new ones, as I observed. He said the only reason to go to 30psi on a plastic and rubber cooling circuit is if you want something to blow up... As I have also observed, teh caps begin relieving pressure from the EXPANSION tank at 20-25psi for emergency reasons.