A john deere head leaking

I may be the odd opinion here, but I think you have a warped head. We had a '48 "A" with high compression aluminum pistons, and over the course of probably 30 years the head was off several times. On one occasion it had a bit of a coolant weep at the upper edge, so I used a michinsts straight edge to check the head with shim stock, and it had about .010" warp at one corner. The block was straight, so I had the head surfaced, and the problem never returned.

If you have coolany leaking on an engine that has no pressure in the coolant, I can only believe that you have a gap caused by a warp.

Honestly, the "A" engine was pretty forgiving on torque, as long as you were consistent. There were many assembled in the barn with no torque wrench at all. It certainly is not as persnickety as a "60", nor as high as my 70 Diesel (208 ft #).

Any engine likes a re-torque when hot, and your "A" will, too.

My $ .02 .

Frank-in-Tallahassee
70D // 855

That means, with good LUBRICATED, easy running threads....Ease back in the wrench, to loosen it a little, then Run the torque wrench up to the full torque without letting the nut stop... The engine MUST be at FULL operating temp for a good while, to allow the entire engine expand before you re-torque... Using this method, you will be surprised how much the Head bolts will tighten... We torqued a set of bolts on a machine press some years ago, and the instructions were to heat the bolts RED a distance of 6' ( FEET ), before torquing...!!!! Now, THAT is TIGHT.!!!!! !

I find no mention of �Running Torque� in my Deere service manual and find no mention anywhere of backing a head nut off on a hot engine before retorquing, that sounds like a good way to warp a head.

This comes from experience gained in writing service procedures for a large machinery manufacturer. Our number 1 problem was technicians torqueing bolts the way they THOUGHT they should be torqued and not using the correct lube on the bolts during the initial torque or at the designated service interval. The type of lube on the bolt or nut can make up to a 30�lb difference in the final torque of the fastener. If the improper type of lube is used or lube is used when not specified, fasteners can stretch or studs can be pulled from their holes.

I am sure Deere did a good deal of field testing before writing the service manuals for their equipment and if different torqueing methods were needed to get the head to seal correctly that would have been included in their service procedure.

I agree a �Running Torque� or dynamic torque is a good way to do the initial torqueing of a fastener but unless that procedure is specifically spelled out in the service manual or a service bulletin it should be avoided on a retorque of any fastener if that involves backing off the fastener first.

While I am sure your intentions were good the use of phrases like �Be sure to use a �Running Torque� on the bolts� and �That means, with good LUBRICATED,� make it sound like that is the way Deere intended it to be done and that is not the case, at least in all the manuals I have on hand. Randy K.

Will P