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-   -   Do I have a cracked block? (https://www.moyermarineforum.com/forums/showthread.php?t=10796)

heinzb 07-11-2018 07:47 PM

Do I have a cracked block?
 
Over the years there have been many posts regarding the issue of having water in the oil.
I also have this problem.
I found the comments and suggestions very interesting and was hoping some would work for me.
I changed the oil several times but the problem did not go away.
I started to check areas mentioned in the forum to determine the cause. I began by doing a pressure test of the manifold and the block.
I tested the manifold first and found that it retained most of the pressure. It lost only about 10% over one hour.
Unfortunately I was not that lucky with the block.
Testing the block with the thermostat in the pressure was gone after half an hour. When I removed the thermostat the reading got a lot worse. It almost immediately lost all of the pressure. I double checked all the fittings to make sure there were no leaks.
Am I correct in presuming that I have a crack in the block?
I did not think it was the head since I changed the head gaskets last year. Perhaps I can remove the head again but how do I test the head for a crack?
Any suggestion/comments are greatly appreciated.
heinz

Dave Neptune 07-12-2018 11:42 AM

Heinze, when you get the head off many things will become apparent. Once the head is clean a close inspection with a magnifying glass may do the trick. If you find nothing in the block especially at the bottom of the cylinders where they sometimes rust through, look for a pin hole.

If the block is OK and you "SEE" nothing cracked on the head have it magnafluxed at an engine shop. Cracks often form around the alternator bracket!!!!

DO pressure check the manifold again!

Dave Neptune :cool:

thatch 07-12-2018 12:10 PM

Heinze, Welcome aboard. When doing a pressure test of the block and head, it is a good idea to "not" include the water-pump in the plumbing setup. This is because you will be relying on the condition of the pump seals to hold pressure.
Tom

ndutton 07-12-2018 06:24 PM

When you retest have a spray bottle on hand filled with diluted liquid dish soap (3:1 water to soap). With the block/head under pressure spray the exterior with the solution. Any external leaks will develop soap bubbles at their source.

This helps resolve gasket and fitting leaks that could result in a poor casting integrity test.

Whippet 07-14-2018 05:53 PM

Thanks MVPs
 
Quote:

Originally Posted by Dave Neptune (Post 113382)

If the block is OK and you "SEE" nothing cracked on the head have it magnafluxed at an engine shop. Cracks often form around the alternator bracket!!!!

Dave Neptune :cool:

Heinz is my neighbor at the yacht club - next dock over. He reached out to me a few weeks back (since he saw my posts on water in oil) and I went over to observe his engine in operation.

Actually ran pretty well - BUT darned interesting observation from Dave Neptune. Upon start up - water seeped out of head right at alternator bracket. Not a gush but a strong trickle.

What are odds that another shot at reinstalling head will fix it? Is Heinz looking at engine removal for further tests? (Heinz I will be in town in a few weeks and can give a hand if I can)

Dave Neptune 07-14-2018 06:48 PM

If the water is seeping out of the stud it may be resealed however if it is leaking from a crack in the head just the head needs to be reset and gasketed.

Dave Neptune :cool:

edwardc 07-17-2018 08:18 AM

Quote:

Originally Posted by Dave Neptune (Post 113427)
If the water is seeping out of the stud it may be resealed however if it is leaking from a crack in the head just the head needs to be reset and gasketed.

Dave Neptune :cool:

Another victim of auto spellcheck? Shouldn't this read "replaced" ?

Dave Neptune 07-17-2018 12:01 PM

Edward, "and gasketed" for the gasket and reset for the process;).

Dave Neptune :cool:

ndutton 07-17-2018 08:52 PM

Quote:

however if it is leaking from a crack in the head just the head needs to be reset and gasketed.
I have read and reread your response Dave and laid back in respect of your forum status and many years of the best forum contributions ever but if there's leaking through a crack in the head, the head is done. Requires nothing short of replacement.

Maybe I misread or misunderstood something?

Whippet 07-20-2018 10:56 PM

more data
 
Hi Neil

I witnessed Heinz's leak with my own eyes. Wasnt coming from a crack in head per se -- but water seemed to be seeping right out of stud at alternator bracket. Can't be sure.

Heinz had replaced head gasket one year earlier. He didnt have compression in one cylinder - so some "expert mechanic" told him it was head gasket. Turns out it was just stuck valve.

So could this be as easy as another shot at gasket replacement? Assume the leak at stud would cause the failed pressure test?

ndutton 07-20-2018 11:06 PM

I didn't have an opinion either way Steve, crack or no crack. However, the area of the head under the alternator bracket is notorious for cracks. Maybe another pressure test, soapy water spray bottle in hand with the alternator bracket removed and nuts torqued down? It would really be a good thing to know for sure where the pressure loss is before fixing anything.

Dave Neptune 07-24-2018 12:53 PM

OOPS
 
OOPS, missed a "not" in a sentence. Haven't been back to this thread.

Whippet~Heinz, because the "area" under the bracket is notorious for being loosened and retightened during the life of the head as well as transferring all of the stress of the alternator to said bracket I would only move forward by removing the head. The leak is most likely from the stud as it is a "flow" as cracks get wet along the crack and sort of weep water. In that same area under the bracket the gasket is somewhat compromised as there is a leak that probably happened due to the alternator loads and improper torqueing. Most any other stud on the head I would try resealing first.

Look very closely at the head for cracks with a good magnifying lens, if your not sure go for the magnaflux.

Dave Neptune :cool:

heinzb 08-06-2018 02:58 PM

update
 
Thanks to all for providing me with tips and suggestions.
I have done some of the tests as suggested and the bottom line is that the block/head only holds pressure for about a half an hour. I did check the Oberdorfer water pump which appeared fine (I found out the hard way why the extended bolt was recommended for the lower slot). I also checked the studs which hold the bracket for the alternator for air leakage as Dave recommended. No leakage there.
I ran the engine afterwards for about 7-10 minutes and water is back in the oil. Based on comments regarding a cracked block and/or head, I am still hoping that it is something else that causes this but it looks like I am running out of areas to check.
I have not checked the plug by the valves for corrosion though, but what else should I check?
Thanks again for all your help especially to Steve who has not only provided me with moral support but also allowed me to use some of his tools.
Heinz


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