head gaskets

[truckguy]

i took my 2.9 apart and found out the cylinder heads were cracked. i took a look at the head gaskets and almost all of the water jackets were completely clogged, and i assume that is what caused it to over heat in the first place. What do i do to make sure that doesnt happen when i put new heads on it?

 

[Tedybear]

Be extremely careful. Head gaskets have some very very different sized holes to control the coolant flow. While the water jacket with the head gasket off may look pretty big? When matched up with the replacement head gasket? You'll probably find the holes to be quite small. Even more so between the cylinders. This threw me for a loop as well, and I figured it HAD to be faulty gaskets. (haven't torn down an engine in 20 years, until my BII's 2.9 with its cracked heads)

All you need to do is clean off the block mounting surface completely of all old traces of the former head gasket. It's gotta be smooth as a babies bottom However you need to use care not to scratch or gouge the block while cleaning it up. It can look discolored (as is often the case when doing it yourself...'shade tree' techs do not have access to machine shops and those highly caustic cleaning machines to get that 'mirror finish') But it's gotta be clean as a whistle! Otherwise the new head gasket won't seal correctly.

And you do know about the head bolt requirements? NO REUSE! Torque to yield design, single use only.

Look at the new gasket when you pick it up, You'll see what I'm talking about for the holes for the coolant. And yep..it's made that way on purpose.

S-

 

[moogvo]

... and don't use stop leak/block sealer in it.