Pressure test oil cooler AQ 130

FillupD

Petty Officer 1st Class
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Jul 5, 2007
Messages
261
I have put a new head gasket in my motor and was thinking that my oil would stop being milky. Although the gasket was bad and the motor runs great after replacement, there is still milky looking oil. The level comes up on the dipstick maybe about a 16th of an inch after an hour of running high RPM's on the water.
I tested it at idle in my driveway for around 5 minutes and the oil was fine so I took it out to see what the oil would do and it got a little milky looking.
I have been trying to find out about testing the oil cooler but really don't see any clear direction. I have replaced the 2 o-rings on the end caps.
Do you take the cooler off and plug the rubber grommet holes in each end and plug the filter hole and try to get pressure to it this way?
I am hoping that the cooler is my problem but I don't know how to go about testing it or setting it up to test. What kind of pressures?
I can do it, (I believe) if I knew some particulars about setting it up. Any help or opinions will be greatly appreciated.
The motor runs and starts great so I am hoping to nail this water in oil problem down and crossing my fingers it is not a cracked block.
(The head gasket was rude looking with some rust spots going across the gasket so I didn't get the head checked thinking the gasket was bad so I got in a huff and just replaced it. I know, bad idea probably.)
If the cooler test is OK, I guess I'll start somewhere else and try to pin point what is going on.
 

FillupD

Petty Officer 1st Class
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Jul 5, 2007
Messages
261
Re: Pressure test oil cooler AQ 130

I drained the cooler and the water that came out was clean. Since I can't really pressure test it I think I am going to say it is OK since there was no oil in the drain.

I warmed it up and don't see any leaks outside the motor.(checking water pump area).
The compression was 179-150-168-179.

Is the next step replacing the exhaust gasket and the riser gasket? Rubber coupler and clamps are replaced already.

Is there something I could check concerning the thermostat maybe?
I would like to troubleshoot everything I can before I have to determine it is a crack in the block somewhere.
 

louiss3000

Cadet
Joined
Apr 26, 2010
Messages
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Re: Pressure test oil cooler AQ 130

Did you check the head carefully when you did the gasket? I'm told these are prone to cracking. I have 2 of these engines in a project boat, but I've not been brave enough to pull the heads yet...
 

FillupD

Petty Officer 1st Class
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Messages
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Re: Pressure test oil cooler AQ 130

I hate to admit it but I did not have the head checked. The gasket was in poor condition so I made an uneducated guess that the gasket was probably the culprit. I does run better with the new head gasket though.

I guess I'm not really against taking the head off again, (and having it checked this time) but I wanted to see if maybe there was some experience out there that had similar problems and may have found a bad riser or exhaust gasket.
 

FillupD

Petty Officer 1st Class
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Re: Pressure test oil cooler AQ 130

I'm still trying to figure this milky oil thing out. I am trying a leak down test and can't get pressure in the cylinders. I can rotate the crank and get air out of carb or exhaust.
I removed the rail thinking this would close all valves and tried it and air come out the carbs and some out the exhaust, still no pressure on the gauge.

I ran it for a while, started it a few times, the thing just runs great but the oil is milky. You can almost see through it to read the dip stick. Could it possibly b moisture trapped in the motor after 5 oil changes?
What am I doing wrong with the leak down? any ideas.
Would I be wasting my time replacing the exhaust gaskets?
Thanks for any opinions and help.
 

Robj

Lieutenant
Joined
Mar 22, 2007
Messages
1,441
Re: Pressure test oil cooler AQ 130

To do a leak down test you need a leak down tester. Really it is the best way to troubleshoot. Not sure what you are using, but they are really easy to use. And there will be small amounts of leakage with any engine. I heard it through the crankcase and a small amount through the intake valves. But the test showed only about 14% leakage on all cylinders so that ruled out any head gasket problem and basically told me that my engine was in decent shape. That is where I would start, and no I don't think that your exhaust gasket would cause the problem.

Have a great day

Rob.
 

FillupD

Petty Officer 1st Class
Joined
Jul 5, 2007
Messages
261
Re: Pressure test oil cooler AQ 130

I purchased a leak down tester with two gauges on it. The air compressor side is set at 90 PSI and the other gauge will not build pressure. When I hook it up, the air leaks through the exhaust and carbs, the front two cylinders to one carb and the other two cylinders to the other one. It seems # 4 leaks more to the exhaust than intake and # 1 has alot coming out of the throat on the carb.

I have the pistons at the top when I check the cylinders. I can see it in the holes and see it at the dist cap. I just must be going about it the wrong way.
If it would not build pressure. it wouldn't run or show up on a compression test like it does, would it?
 
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