Cracked block - What to do ?

[dotdat]

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Working on restoring my 1974 Datsun 620. I pulled the oil drain plug and about a pint of anti-freeze coolant ran out followed by some nasty, brown colored oil.

 

Next step: I blocked off the lower block return, then pulled out the thermostat and filled the opening with about a gallon of 50/50 anti-freeze.

 

There now is a very slow dripping of anti-freeze comming out of the oil drain. It appears that it has a cracked block. The truck was parked outside for several years and I would guess it contained coolant not mixed strong enough for our cold winters. The freeze plugs seem to be intact.

 

Question: What the hell do I do now?? Any repair possible? Or is it toast. Your comments please.

[Skib]

sure its not a blown head gasket?

 

 

if the block is indeed cracked then youl need to replace it.

[datzenmike]

Another week point is the timing chain cover that holds the water pump. If the cover is cracked or eroded around the pump water will drain down the front of the block into the front of the oil pan.

[68Datsun510]

Yeah this aint no Chebby, our blocks STRONG!

[ggzilla]

JBWeld

[Draker]

If it's the block.. you can have it repaired.. but its not worth it. Find another good one or look at the suggestions above.

[EricJB]

If it froze and cracked anything, it would most likely push out a soft plug as well. My money's on a head gasket/ timing cover issue.

[dotdat]

Sounds very logical that the problem could be in the head gasket or timing cover. I'll pop off those two things and looky-looky. Oh yes, will the leak be quite obvious by looking ??

[ggzilla]

Not always obvious by looking.

 

Why pop the head off? If the head gasket is OK, you just created a bunch of time and money hole.

 

Find the leak before you do anything. Do a pressure test on the cooling system. Or a leakdown test on the cylinders.

[TFM1066]

unbolt the motor mounts lift the motor a bit and pull the oil pan, then put some pressure in the cooling system, get back under the motor and you'll see where its coming from. a little time and a pan gasket.

[ggzilla]

Or leave the pan on. Listen with a hose while pressuring the system.

 

Is air leaking sounding loudest?

* Through oil fill hole? If not, no need to pull the oil pan.

* Through carburetor? Leak is perhaps in intake manifold, intake gasket or cylinder head

* Through exhaust pipe? Leak is perhaps in exhaust gasket or cylinder head