Mercruiser 3.0 LX Block and Head air pressure test , can't find the leakage

[buckz6319]

I have a 1993 Mercruiser 3.0 LX that may have had possible freeze damage internally to the block...It is a Ga boat Motor.

I bought the boat with frappuccino engine oil, knowing that I may have to replace the engine.

I have done all sorts of testing, and now are at the point that I need to pressure test the engine block and head as a whole unit, with manifold slid away from the head, and not connected to the air supply. The manifold may be bad, and I will get to pressure testing it.This is a sea water cooling system on this engine....

My issue...I have a air pressure leakage going on, however I can't find where the air leakage is going to.

....I put 20 psi in the water jackets of the head, and block only, through the t-stat housing, with the t- stat removed, and necessary hoses blocked off..and tested for leaks.

I can watch the pressure drop fairly quickly after pressurization, however can't find the leakage. I pulled each plug, no air escaping , I pulled the dip, no air escaping, none coming from the valve cover. I sprayed around all the head gasket to block mating surface, no air leaks, water pump, no leaks, casting plugs, no leaks, pan drain plug removed, no air leaks...I have pumped in probably pressurized this system 5-6 times with the same amount of air, and each time it leaked down....
........where is all that pressurized air going???

I am using a certified gas pipe pressure gauge, for this testing. I see them all the time, thought I could use one for this test

I would appreciate any advice, information, gut feelings, about what is going on

I would appreciate your time!!!

[Capt.Insane-o]

water pump

[flabum1017]

Are there any signs of water in the exhaust or intake ports?

[buckz6319]

Are there any signs of water in the exhaust or intake ports?
I thought I would run my own dye test today, on the water jackets of the head, and block...with manifold removed


I took a 32oz cup of water and added 1 full tube of Dark Green food coloring dye, mixed it up, and poured it into the t- stat hose. I then pressurized the system with 20 psi and after about 20 minutes, I drained the engine oil, (don't know why it held pressure after putting that water in it) "weird" can't explain that!


here is what I found in the engine oil...now I have to figure out " Head or Block"
http://i494.photobucket.com/albums/rr310/buckz6319/0323141340_zpsslwfe52b.jpg

[buckz6319]

water pump
thanks for the input, not sure about that pump, I sprayed all around it with soapy solution, and no signs of leakage around the gaskes

I did however do a DIY home brew dye test, and just posted to the last comment
thanks!

[Capt.Insane-o]

They crack at the bottom of the water jacket along the skirt of the block most of the time when frozen, I've never seen a broken head from freezing. Time for a new one in a box.

[buckz6319]

They crack at the bottom of the water jacket along the skirt of the block most of the time when frozen, I've never seen a broken head from freezing.

ok, I did not know that, thanks for that valuable piece of information
I may have to put her on the stand, and have a look inside

[Capt.Insane-o]

When you pull the pan off you'll prolly find it cracked along the camshaft side.

[buckz6319]

I had this engine on a stand and apart, searching for a crack inside the block. I am sure that I checked the camshaft and lifter area out pretty tight, before I put it back together...however if it was a hairline crack, on the inside of a cast iron block, I could have missed it.

I know the correct way to check for cracks is to magnaflux the block and heads, however to have the block magnafluxed, I would have to had it completely torn down and cleaned. I opted not to do that at this point, didn't want to put a lot of money in it, knowing something could be wrong with the block

[powerabout]

Check number 1 at the front where they machine the outside of the bore casting from the water pump side for clearance.
Its so thin a ball peen hammer could bust through when new!!
I had one that we only found the crack after we left it outside for a few days and the rust line showed up

[buckz6319]

Check number 1 at the front where they machine the outside of the bore casting from the water pump side for clearance.
Its so thin a ball peen hammer could bust through when new!!
I had one that we only found the crack after we left it outside for a few days and the rust line showed up
Thanks! Did not know that was a weak area. I will check that this evening
And report back

[Capt.Insane-o]

Goodson makes an ultra violet dye kit, or sometimes you can find them at a good auto parts store.