leaking head gasket after replacement

[jfgray]

I just completed replacing the head gasket on my Ford 641 tractor. Starts and seems to run good but after warming up and putting under light load I am seeing some antifreeze bubbling out from the head.

I had the head checked and planed and got new head gasket from ford dealer. Cleaned the block. Used copper sealant spray on the head gasket. Followed tightening sequence and used torque wrench - first half way to about 40 ft lbs and then again to full 80 ft lbs.

The original leak appeared in the same location - along the head / block line on same side as the plugs.

So what do I do now?

I am considering:

- warming up tractor to normal temp, then removing gas tank and valve cover to re-torque the head. When I originally torqued the head, it was only about 40 degrees. So maybe when it warms up, it is not torqued as tightly.
- using a head gasket sealant. Any one had any experience with this and if so, what sealant would you recommend?
- replacing the head gasket again but not sure what I need to do differently to not have the same problem.

All comments and suggestions appreciated.

Thanks

 

[old]

One every tractor I have ever done it is said your suppose to re-torque the head after you have ran it till good and warm. So your problem may well be you do need to re-torque the head

 

[dannyidp]

Did you have the head magnafluxed? There could be a hairline crack it goes above the seat that's hard to see. It might be that you need to put some stop leak in it I do not like doing that kind of thing but there is some good stuff on the market that works. If it's just a little small leak it will seal it up.

 

[jfgray]

Yes, the head was magnafluxed and planed. Shop said it was ok.

Do you have a preference for the kind of stop leak to use?

 

[jfgray]

That is good to hear. I'm on my way to try that this afternoon.

 

[old]

If/when I use a stop leak I use Bars copper sealer. Found it does better then any other one I have ever tried

 

[showcrop]

The valve cover is designed to roll out without removing the tank.