Cracked block or blown head gasket

Tiny
GIVIE
  • MEMBER
  • 1961 CHEVROLET TRUCK
  • V8
  • 1,000 MILES
I have a restored 1956 Chevrolet truck with a small block, supposedly rebuilt. The motor began smoking out the rear side exhaust. I ran a compression test and all cylinders were 135-145 and the spark plugs all looked good. The truck ran good, didn't heat up nor any fluid leaks. Thinking it was possible a blown head gasket I removed the passenger side head a found a damaged head gasket and water in 1 and 7 cylinders. Since I had the motor tore down I decided to remove the driver side head and to my amazement I found water in #8 cylinder yet the gasket was in good shape.
Know I confused. How could water be in both sides. The intake and head bolts all seemed to be torqued down.
Any help would be greatly appreciated.
Monday, June 24th, 2019 AT 12:14 PM

11 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

If you had a leaking intake manifold gasket, that would explain the issue.

Did the intake gasket look damaged?

Roy
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Monday, June 24th, 2019 AT 12:48 PM
Tiny
GIVIE
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  • 6 POSTS
The intake manifold gaskets did not look damaged, yet there is oil deposit inside each manifold channel that corresponds with the pistons that have water in them. Also one additional note, the manifold channel on each side of the intake manifold that is in the center, lines up with the carburetor, is full of oil. I previously checked the PVC valve and it rattled and assumed it was functioning.
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Monday, June 24th, 2019 AT 3:44 PM
Tiny
ASEMASTER6371
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It could be rings for that issue.

A wet and dry compression test will verify that.

https://www.2carpros.com/articles/how-to-test-engine-compression

Was there any coolant in the oil?

Roy
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Monday, June 24th, 2019 AT 3:46 PM
Tiny
GIVIE
  • MEMBER
  • 6 POSTS
No water in the oil, and no oil in the radiator fluid.
Supposedly the engine was rebuilt, I know they all say that, but visually the
motor is beautiful. Also all piston cylinders do not have any edge at the top. The valley below the intake manifold is in perfect condition, no sludge or water deposits.
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Monday, June 24th, 2019 AT 3:57 PM
Tiny
ASEMASTER6371
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I would have the heads checked to be sure they are not warped.

Roy
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Monday, June 24th, 2019 AT 4:02 PM
Tiny
GIVIE
  • MEMBER
  • 6 POSTS
I take them in tomorrow.
Why would oil be in the center channel on each side of the intake manifold which is below the carburetor?
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Monday, June 24th, 2019 AT 4:13 PM
Tiny
ASEMASTER6371
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Rings, as I stated before. That's why you need to check the rings.

Roy
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Monday, June 24th, 2019 AT 4:22 PM
Tiny
GIVIE
  • MEMBER
  • 6 POSTS
Well, I ssume that means pulling the motor and dismanteling it. Is that correct?
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Monday, June 24th, 2019 AT 4:29 PM
Tiny
ASEMASTER6371
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You are this far. You might as well pull it out and put it on an engine stand.

Roy
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Monday, June 24th, 2019 AT 4:32 PM
Tiny
GIVIE
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Okay, thank you.
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Monday, June 24th, 2019 AT 4:50 PM
Tiny
ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
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Monday, June 24th, 2019 AT 4:51 PM

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