5.7 Water in oil ??

sillydilly

Seaman
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Sep 10, 2012
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hello a few of you may remember me from a few months ago about an engine swap I've recently done. I had a 5.7 with a severely cracked block that was shooting milkshake out of the oil dipstick.

I swapped it out for a good running truck 5.7 with 135psi on all holes. kept marine cam.

ran it for well over an hour of combined time in the driveway with no issues.

took it out for its first test run and about 5 minutes down the lake of incredible running, k let off throttle and smelled burning oil. I slowed the idle then it just died. popped off
the dog house and seen milky oil seeping from the air cleaner into the intake and boiling and burning. dipstick was whitish milky ..


i never removed heads from
truck engine, kept it all intact. wondering where the water is coming from ?
 

bruceb58

Supreme Mariner
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Mar 5, 2006
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Do a pressure test of your cooling system. I would be suspecting the install of the intake manifold.

If you swapped intake manifolds, did you inspect it for cracks?

Is your oil level high? If not, did you replace your manifolds which were probably also cracked?
 
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sillydilly

Seaman
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used marine intake. I will check oil level. did not replace manifolds. how would I pressure test that ?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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If the block was cracked, manifolds are most likely cracked too
 

bruceb58

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Buy new manifolds or pressure check them. Need a block off plate for the riser connection.
 

Bondo

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used marine intake.

Ayuh,..... Was it fully inspected for freeze cracks,..??..??

If not, I'd start there,.....
 

sillydilly

Seaman
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No Title

looks like towards the rear of
the engine is where the issue lies ?
 

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Rick Stephens

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Aug 13, 2013
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Probably shouldn't be looking to intake as the problem. The exhaust manifolds are double wall and have water flowing around the outside of them to keep them cool. Th water stays separate from the exhaust until after the elbow where the first rubber connector attaches to the Y pipe. Then the water is dumped in with the exhaust and cools the rubber connector, the Y pipe and the outdrive itself from the hot exhaust gases.

If you have a cracked exhaust manifold you wil get water on the exhaust valves and potentially inside your engine. Ultimately, you can end up with enough water in a cylinder to break pistons, bend robs and crack heads. Pulling the exhaust manifold off will enable you to at least see if the exhaust valves are rusting. That's a pretty good indicator.
 

sillydilly

Seaman
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Rick that is a very helpful reply, thanks !!

I can't remember how I pulled the engine but I sure hope that I can take off the manifolds with ease and inspect them ....
 

wahlejim

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Another easier check without pulling manifolds is to pull your plugs. When my exhaust went this year, the motor hydrolocked and water came pouring out of the spark plug holes on my engine.

Manifolds are easy to pull compared to installing a new engine. Make sure you have a new, oem gasket set ready to go.
 

sillydilly

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i pressure tested both manifolds and everything seems in check except the gaskets..... would make sense how the water is getting into the engine.... anywhere should I check ?
 

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Bondo

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took it out for its first test run and about 5 minutes down the lake of incredible running, k let off throttle and smelled burning oil. I slowed the idle then it just died. popped off
the dog house and seen milky oil seeping from the air cleaner into the intake and boiling and burning. dipstick was whitish milky ..

Ayuh,..... With the motor runnin' down the lake, a hole in the exhaust won't put water into the oil,....
It has to get past the piston rings,....

Sounds like ya got another cracked block,.....
 

sillydilly

Seaman
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Sep 10, 2012
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62
bondo... this motor I put in was a family members and it was tested at 135psi in all
cylinders in a well running truck that doesn't burn / use oil or antifreeze. I'm confident the block isn't cracked - it's been 20 degree Celsius the whole time I did the swap so I just can't see how it would be cracked.
 

Toypirate

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Aug 24, 2011
Messages
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Check the exhaust shutters.

I'm not sure the camshaft spec on a truck engine is correct to prevent the overlap between exhaust and intake lobes from drawing water back into the engine at idle, I've seen it on the 454 inboards just not sure of the small blocks and I/Os. anyone?
 

nateo

Petty Officer 1st Class
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Apr 13, 2014
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Could be a vac leak creating condensation. ok, here's another thing. Did you use a thick bead of silicone/gasket maker on the ends of the block or the gaskets that came in the package? I read in a thread once that most shops throw the factory ones away and use gasket maker. I've also read to use both.

I had milky oil once in my bmw, shop wanted two thousand to replace head gaskets. I went out and took another look. Turns out I had a tube disconnect from my intake. After reconnecting that I took it for a long drive, water burned off and problem was solved!
 

sillydilly

Seaman
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Sep 10, 2012
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Mechanic used new intake gaskets as well as silicone like crazy.

I did a pressure test for exhaust manifolds. blocked off with plate at riser connection and applied 20psi at the plastic water inlet. as opposed to allowing it to hold air (was direct to compressor) I submerged the entire unit and waited for bubbles. nothing came about so I believe those are well.

I did NOT inspect the intake or pressure test it, it is cheaper for me to replace it ($50 ish) and assume it's cracked as well.


Once the new intake is on I will compression test the engine and try to diagnose a head gasket


EXHAUST SHUTTERS?????

first I've heard of these. did my research, little flapper dong at the Y? best be seen by pulling out drive or down through the elbows ??

I recall the engine running fine and once I deaccelerated is when i instantly had issues. is it possible my flappers gone and this entire time my engines been good but I just sucked in a bunch of water? wouldn't that hydrolock me ? milky oil was found in the rear of engine ...


recap

- Pressure testing exhaust manifolds
- Sand/flatten/silicone the **** out of riser connection with new gaskets
- Assuming cracked intake, replacing
- Compression test to diagnose head gasket failure
- Find the flapper and make sure she's there


Anywhere else I should check?? Thanks !
 
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