Tecate 3 Leaking coolant out of the head after rebuild

[yaegerb]

Did you check for true on the cylinder and head surfaces? Did you find any gouges on the cylinder surface?

[loganm]

You replaced the head or the jug? Did you use the same head or a new one? Take the damn thing head and cylinder to a machine shop and have them check all surfaces and machine if necessary.

[Twittle]

The studs being a different lengths shouldn't really matter unles you are using acorn nuts and they are bottoming out or you are running out of thread before it is tightened all the way. Like multiple people have said you need to check both the cylinder and head for flatness.

[niftylittleguy]

I checked the cylinder and the head and they are completely flat. There is no scratches or anything in the head.

[RubberSalt]

If all is true, then this was a bad or damaged head gasket or the bolts not torqued properly, one or the other.

These are a dry fit. Everything must be 100% clean. I use brake clean on the metal prior to installing.

[oscarmayer]

as Yaegarb says you need to check for flat straight surfaces. if your not comfortable, take the cylinder and head off and take them to a machine shop to get decked flat for sealing. then use new gaskets to re-assembly them. I have not done a tri-z if us uses O-rings like the YZ motors, then measure the stock o-ring thickness then measure the inside edge where the oring sits in the cylinder and do a google search for silocone orings in that size. you will probably be able to find higher quality ones at a good price shipped. I imagine if O-rings you have 2. 1 inner for sealing off combustion chamber from water and then water from outside of cylinder. so you would need 2 orings.

good luck! but either way get them decked flat. do not use a sander..

[86T3]

I'd check to see if your studs are pulling out of the head, I dont see why there would be different length studs.

[fabiodriven]

What exactly did you do to the head that constitutes a rebuild?

He means the cylinder. TecateDan does that all the time as well, referring to the cylinder as the head. I think it's nautical guys who do that mostly because of the term "power head" for outboards or something, I don't know. Just a theory.

Guys rocket science this is not. A first-gen Tecate top end is as easy as it gets. Make sure all mating surfaces are true, look for cracks or any other issues, and use good gaskets.

[nd4speed]

Is this cylinder sleeved?

I have had a similar problem with head nuts torqued to spec with coolant in it right away. Had to start over with new head gasket and melt it with no coolant in it. Also tightened nuts real snug then checked after heat cycles.

Had lots of blown head gaskets and pulled studs on the 86/87. And Bad sleeve deck heights on 84/85.

[niftylittleguy]

The cylinder is sleeved. So should I buy new studs or keep the old ones?

[yaegerb]

if the studs are all at different heights I would buy new ones.