2000 Explorer 4.0 SOHC coolant leak

[nrtravis]

Hi,
Can anyone tell me the part number for the o ring that goes between the thermostat housing and the block on a 2000 Ford Explorer xlt 4x4 with the 4.0 SOHC engine. The thermostat housing is the one with the screw in sensors. I have replaced the whole thermostat housing twice before but the o ring has flattened and seeping coolant now. It seems that no one can get the right one. I went to the local ford dealer and they didn't even have it in stock. I ordered 2 from rock auto both fel pro 35617 and 35673 and neither are correct.
I believe the 35673 might be for the ones after 07/24/00.
Thanks for any help !!!

 

[swshawaii]

Although the lower "rubber band" seal seems loose, hundreds have installed them without issues. The lower housings are very sensitive to over tightening that warps the housing and causes the seams and lower seal to leak because of the pressed in bushings. Are you tightening to the factory recommended 8 foot pounds? Is it an aftermarket Dorman or Four Seasons housing?

 

[nrtravis]

Believe its a dorman. I replaced it over a year ago and it worked fine. It recently started leaking through the bottom o-ring. I used a leak tester to verify after removing the upper intake. I removed the thermostat housing and the o ring was collapsed. The housing looks fine. I replaced it with one i got at the parts store. They did not have the right one and the guy guessed at it. It worked for a couple days and started leaking again. Want to get the right o ring for it and re install. Thanks!

 

[albi1cnobi1]

This is the part number that Ford lists - W702837-S300.

 

[nrtravis]

Thanks, got one on the way!

 

[albi1cnobi1]

NP. Glad to help.