John Deere 4200 replacement radiator cap unavailable with rubber sealing washer?

[Mark from Maine]

Year 2000 JD 4200 new radiator cap missing rubber seal? Just purchased part number AM102893 radiator cap. My original cap has two rubber seals. One immediately under the cap that seals the cap to the radiator opening. The other smaller seal is located at the outer end. The large rubber seal on the underside of the original cap is deteriorated with cracks so I ordered a replacement cap from Green Farm Parts thinking it would come with the rubber seal as there is no listing for just the seal. The cap was delivered with no large seal beneath the cap. I called Green Farm Parts and spoke with the parts dept . They looked at a cap on the shelf and it also has the seal missing. He did not see a listing for just the seal either. He said JD may have had a change with the cap design. If I remove the seal from my original cap it looks identical to the new cap that comes without a seal. I find it hard to believe it will properly seal being just metal to metal.

Anybody run into this and have anything to add?

Thanks,
Mark

 

[banjodunn]

G'day I'm thinking your tractor has a recovery/expansion bottle in the cooling system ie a small bottle that the overflow hose from the radiator goes to, the function of the upper sal is to seal the cap to the neck so that when the system cools down coolant is drawn back into the radiator from the recovery/expansion tank. Without that upper seal your system will not work as it was designed to I would be looking for the right cap for it, does not mean you have to go to JD just someone who knows what they are doing.


Jon

 

[Mark from Maine]

Thank you Jon for the "how it works" explanation. You're correct, the tractor does have the recovery/expansion tank. Another TBN member sent me a private message suggesting I go to a auto parts store and pick up a radiator cap. I will do that.
Mark