Engine: Head bolts question + followup

[Pentax645]

I have the replacement engine installed in the truck and started it up yesterday. Today I noticed that antifreeze which I installed yesterday is seeping up under the center head bolt and has already filled up two spark plug recesses. This is a Champion 170 ci engine. The head gasket is new.
I understand that some of the head bolts also seal the coolant jackets. The problem must be that either the block/head is cracked or the bolt is not sealing the cooling jacket adequately.
If I remove the head and find no cracks, what can be done to seal the bolt? I suppose one can drill/tap the block hole one size larger and put in a wider bolt.
Does anyone have any other ideas?
Thanks.

[sweetolbob]

I hate to ask a dumb question but did you use sealer on the headbolts. It's always necessary on the bolts that go into the water jacket?

Bob

[Pentax645]

Well, I hate to be stupid, but no, I didn't. You finished your second sentence with a question mark but I think you are saying that it is always necessary. What kind of sealer should be used that would work? Thanks.

[DieselJim]

I use pipe dope.

[Pentax645]

I hope I didn't come across negative in my response. It was not my intention.

[jackb]

....ah....don't go so far so fast.... A few things come to mind: out of surface head and /or engine deck(block). If both were not examined for warpage or heat distortion, you might have mis-mated surfaces. How about the head gasket ? Did you use any sealant ? Varying opinions from many. Did you tap all the head bolt holes and true the bolts and dip slightly in oil or a film of sealant ? And finally, did you re-torque the heads once they warmed up to temp and then 500 or so miles later ? Any of the above can be your problem(s). Start with the easiest 1st.

[Pentax645]

I'm not sure I know what pipe dope is. Surely you don't mean the product that plumbers use on water pipes, do you?

[sweetolbob]

I hope I didn't come across negative in my response. It was not my intention.

No reason to suspect you were negative in your response. I used Permatex #2 but they as well as others make specific thread sealers. You'll get other suggestions for the forum, certainly by folks that know more than I do but you could just go to your local auto store that does rebuilds and buy what they like.

It's prudent to check all the other variables suggested but I was just trying give you a quick idea of a possible solution that would not require disassembly. In any case, head bolts should be cleaned and lubed to give good torque values.

Best, Bob

[DieselJim]

I'm not sure I know what pipe dope is. Surely you don't mean the product that plumbers use on water pipes, do you?

Yes. Coat the threads. Use non harding.

[52-fan]

I don't remember putting anything on the bolts in my Champion engine and it was fine. To be safe, check the shop manual and do what it says.

[Pentax645]

Follow up on Head Bolts

In an earlier post I wrote that antifreeze was seeping up from underneath the center head bolt on my 170 ci Champion motor. The advice I received was to apply pipe dope or aviation gasket material. That was good advice. After draining the antifreeze I loosened the bolt a turn and found that it wobbled quite a bit while still screwed into the block. Apparently corrosion takes its toll on the threads and the clearance loosens up. Although it was proper to simply apply light oil to the head bolt before installing it in a newer motor, it is now necessary to apply a sealer to prevent the antifreeze from working up through the threads.
Thanks to all who responded to my inquiry.

[RadioRoy]

It might be time for a few new head bolts. You would not one to break off in the block.

[GinettaG12P]

It sounds like there is a greater chance of stripping the threads in the block than breaking the bolt.

[Pentax645]

The threads in the block are still sufficient to allow me to lift the motor, trans and overdrive by lifting from two head bolts. With that, they are more than adequate to hold the head down. Of course, I'll keep a proper antifreeze solution in the motor.

[jackb]

....I'm in the company of you might need to replace the head bolts. Lifting angularly and sharing that weight with at least another screw or 3 isn't anything like compressing the head and block together to sandwich a gasket under constant, repetitive pressures.....not to mention you're continuing to do damage to the screws and the deck......GL