Hello,
I am finishing Toro 1966 , engine rebuilt and assembled, seems to be correctly.
but,
after pouring coolant into the system and making a few turns from the starter without start the engine, I noticed that the liquid was mixed with the oil. the engine is in emulsion, the level has doubled.
new gaskets.
after removing the valve covers, I noticed drops of pure coolant on the springs and housing.
and got through the valves to the cylinders.
I suspect it's getting through the intake manifold

Any suggestions ?

 

Did you use the turkey tray intake manifold gasket? I've always had difficulty getting those to seal properly. Don't use the rubber end seals that are provided. Instead, use Right Stuff gasket maker:


Also, you can cut the turkey tray from the side rails and ditch the turkey tray or you can get an intake manifold gasket that just has the side rails. Use blue/black RTV at the corners and around the water jackets and use red high temp RTV around the exhaust ports.

 

Did you inspect the water pump backing plate? They pit and can rot thru causing the problem you describe...

 

The above posts are the most likely ways coolant enters the oil pan. My bet is on the intake manifold.

 

Water pump backing plate is ok
Tooday I check intake manifold

 

Unfortunately, the new gasket is in accordance with the instructions and the coolant is leaking again from the plug in the oil pan. I poured the fluid without the manifold below the holes and it started to drip

 

Then you need to look at head gaskets.

 

Gasket issue between the front cover and the block???

 

Unfortunately if it's not head gaskets, then it could be a cracked block or heads. Hope it's the head gasket.

 

I know, the engine was disassembled and reassembled by me, I didn't notice the cracks. But there may be some that are invisible or in a place like this. So hopefully it's a pump or head gasket. I hope ........

 

Best way to have everything checked is to have heads and block magnafluxed.