compact 4320 coolant leak

[oldtimer 66]

FYI this post concerns the coolant leak at the upper radiator hose connection on the 20 series tractors. They maybe called a 4024 ( 4 cylinder version/ 2.4 liter ) and or a 4030 ( 5 cylinder version/ 3.0 liter ). As noted in some other posts this is some what of a problem on some tractors.. My tractor has had this problem along with other coolant leaks since I bought it. The forward end cover/ gear cover is made of investment cast aluminum. If you inspect the lower radiator hose connection surface on the forward end cover you will notice how perfectly round it is. It is void of any grind marks and or hand dressing of the surface. The retention ring that is cast in and sets proud of the main diameter is clean precise. It is a good circular surface for making the lower radiator hose connection. I have not had a coolant leak at that connection and did not need to replace the lower radiator hose after almost 9 years. Now on the upper radiator hose connection where my coolant leak has always been is a hand dressed surface. This connection area has been hand ground to remove either the risers and or feeder runs for injecting the aluminum into the mold. The risers and or feeders are at 180 degrees of each other. The sides of this connection diameter have been hand dresses with some type of abrasive wheel to remove the riser and or feeder runs and this hand dressing has made the circular diameter egg shaped. The retention ring is completely remove for about 30 degrees on each side of this hose connection diameter. Depending upon how I measure it the hose diameter is any where from .120 " to .180" out of round. Needless to say I have put on at least 3 upper radiator hoses because of this egg shaped cast surface. I know the dealer also put on at least one upper radiator hose during my warranty period. This is a relatively small diameter and this out of round condition aggravates trying to make leak proof connection. Yes you need to keep tightening the hose clamp over time and you need to position the hose clamp just so and after some period of time you cannot tighten it any more to keep it from leaking and now you start over with a new upper radiator hose. There was not a lot of fore thought in the design of the mold for this casting. The upper radiator hose connection surface should not of had either a riser and feeder on the upper radiator hose connection surface unless that surface was going to be machined after being cast. Note that this extra machining would increase the cost of this part. So somehow this looks like cost versus quality, hey. I can visualize the design review because I know somebody in that meeting said " that's no problem" and when you hear that phrase that is when the problem starts. I will have other posts concerning the rest of my coolant leaks on my tractor to follow. Like I say my tractor has more leaks than the NSA.

 

[AKfish]

You've gone to a lot of effort to determine the extent of the problem - all the way to measuring the out-of-round dimensions to the .001th's.

A couple of questions, nevertheless. How difficult would it be to re-work the top hose connection into a better round shape? If you were to use a smaller hose clamp (without the rubber hose) and tighten it down until the metal began to conform to the circle clamp. Or, I have seen circular jaw vise-grips that you could squeeze the upper tube into a cleaner circle. Obviously, you won't be able to get it perfectly round, but even a minor change could stop it from leaking.

One additional trick that I recall from the "old days" was to cut a small slit in a tube that you wanted to compress without bending or crinkling. That relieves the longer or oval section to move into a circle without bending.

AKfish

 

[oldtimer 66]

Hopefully when I get the FEC off I can rework this area. But thanks for the input AKfish. The hose connection cross section is probably .19/.25 wall thickness in that area so to deform it would probably not be possible plus it is a difficult area to get at. My best game plan would be build up the area with weld ( TIG ) and I have a neighbor who has a Bridgeport fly cut a new diameter, eliminating the retention ring and or welding a retention ring on in that area after machining. A new FEC was $ 540 but now it is approx. $280 with the gasket. Figure that. Maybe I should change the name of my tractor from a John Deere to as Snowden Tractor because it leaks so much. LOL.