L89 Coolant Leak out No. 3 Cylinder. Help?

[William H.]

I just had my 1968 L89 engine rebuilt and when I filled the coolant into the engine, it leaked out the No. 3 cylinder. Confirmed by removing spark plug and turning over engine with water coming out. I pulled the head, visually checked for cracks or warping, put on a new head gasget and retorqued the bolts. Installed the intake manifold and properly sealed everything. Prior to rebuild, the engine had spun a rod and excess metal damaged the cylinders. The cylinders were bored out and new crank, pistons, etc. It's still leaking out the number 3 cylinder. Any ideas....the engine did not do this prior to the rebuild. Thanks.

[Clem Z.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

I just had my 1968 L89 engine rebuilt and when I filled the coolant into the engine, it leaked out the No. 3 cylinder. Confirmed by removing spark plug and turning over engine with water coming out. I pulled the head, visually checked for cracks or warping, put on a new head gasget and retorqued the bolts. Installed the intake manifold and properly sealed everything. Prior to rebuild, the engine had spun a rod and excess metal damaged the cylinders. The cylinders were bored out and new crank, pistons, etc. It's still leaking out the number 3 cylinder. Any ideas....the engine did not do this prior to the rebuild. Thanks.

take the head to a good auto machine shop and have it pressured test. did you use non hardening permatex on the head bolts ???

[Page C.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

Agree with Clem. Have the head pressure tested. If heads have been cut for harden seats, it could be leaking behind the seat.
This is why I avoid having harden seats installed, especially with the limited mileage these cars see today.
Regards,
Page Campbell

[Michael H.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

I had this happen one time on a 327, had it bored .060 and I found pin holes in one of the cylinders. We found out later that either the casting had shifted during the manufacturing of the block or we had excessive corrison in the water jackets. I hope this is not the case with your motor.

Mike

[William H.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

Thanks for the good insights. I'm off to remove the head.

[William H.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

I'll keep my fingers crossed that it's the head and not the cylinder. Thanks for the feedback.

[Clem Z.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

I'll keep my fingers crossed that it's the head and not the cylinder. Thanks for the feedback.

if it is the cylinder they can be sleeved

[Gene M.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

Much simpler check while head is off is the valve guide in the head goes by water port. Is press fit good? Is it sealed good?

This is an issue with porous/pitted thin cast iron heads and may also be with aluminum.

[John H.]

Re: L89 Coolant Leak out No. 3 Cylinder. Help?

Agree with Clem. Have the head pressure tested. If heads have been cut for harden seats, it could be leaking behind the seat.

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In his case, he has hardened seats - L-89 aluminum heads all had hardened valve seats.