670 coolant in crank case

[r9559]

My friend had recently rebuilt his top end on a 98 670. He noticed a leak around the base gasket. Ripped it apart and crank case was full of antifreeze.
Is it a bad base gasket or cracked case?

 

[eazyduzit509]

Probly a gasket. Havn't heard of a cracked case on the 670's.

 

[pernikm]

Clean (meticulously) or replace studs/bolts and lubricate. The corrosion or lime on threads can significantly reduce preload in the fastener even tho it is torqued to spec. IE. The friction causes the nut to stop turning before there is enough tension in the fastener. As much as 50% less.

Karl

 

[ak]

Did Your friend coat the base gasket (both sides) in loctite 518? Your suppose to. And I recomend OEM gaskets The holes line up better.

Also use new o rings on the top of the cylinders.

 

[arcdoo]

seal

could be the water pump seal on the shaft,or the seals on r/v shaft.

 

[ak]

If the water pump shaft is bad the oil will be very milky color. Did the sled have a leak before he tore it down? Im betting its his base gasket are head gaskets.

 

[DWHalverson]

If any of the RV shaft seals are bad they will not leak anti-freeze into the case. If these seals go out you will have coolant or oil coming out of the weep hole in the water pump cover. The RV shaft seals on the disc side will drool oil into the RV cover assembly and then into the case.

could be the water pump seal on the shaft,or the seals on r/v shaft.

 

[r9559]

never had coolant issues before. He said the case was full of antifreeze. How will that affect the crank bearing? Crank may have been submered for a month or so. He had rebuilt it this fall and put a few miles on it. The coolant must of seeped in while sitting. I think the motor ran ok otherwise.