Community Forums

8.3Oilbuner · 03-30-2017, 10:32 PM

HI all; I see in previous posts owners have replaced the radiator coolant tank with the new nylon ones. The previous owner had a truck shop replace the tank with the new nylon one and new brass 90 degree fittings on top and a new Ford low coolant sensor. I don't know what the truck shop used for sealant around all the threads, but they all leaked. Took all fittings out, cleaned threads and resealed with Permatex Ultra Black RVT Silicone Gasket Maker. Good for oil and all fluids except gasoline. Everything has been good for 1 year and about 1K miles. Got the coach out for a run today and came out to check oil level later. Noticed antifreeze on alternator pulley. Coolant was leaking from around the threads of the low coolant sensor. So I sucked the coolant out of the tank to reseal the sensor. When I went to remove the sensor it came out real easy. Noticed that when the truck shop went to drill the hole out for the threaded plug that the sensor was to go in, they did not drill all of the nylon out of the bottom of the hole. The shoulder of the sensor was not going all the way into the tank. Got out a drill and just opened up the hole by hand so now the shoulder of the sensor goes further into the tank. Resealed with new Permatex and installed the sensor. Sensor now screws further into tank. What have others used for a thread sealer and how far should the Ford sensor screw into the tank. I sure don't want to strip the threads out and have to buy a new tank. Your thoughts please. Thanks

10Boomer · 03-31-2017, 04:19 AM

Weird the new nylon tanks come threaded already? Most sensors come pre-doped for lack of a better term. No need during initial install rouse any thing.
Note never over tighten either, makes it difficult to remove later and you may strip it out.
If you have to reseal, I use liquid teflon, let it cure overnight would be the best. If nota few hours you are good to go

Ted Lambert · 03-31-2017, 08:27 AM

The sealant you used. Did it say thread sealant? If not you may not have used the proper sealant.
I have not seen silicone used for threads and would not use it myself.

I go to industrial supply shops that handle hydraulics and get a paste type sealant.
The only thing is it normally not easy to remove later.
Also I would not use it on a hot water drain.

Here are some good examples from Amazon

https://www.amazon.ca/s/ref=nb_sb_ss...=10TILORKO7JK2

10Boomer · 04-03-2017, 12:08 AM

I use 59235 Permatex High temp sealant

8.3Oilbuner · 04-03-2017, 02:53 PM

Hi all; I want to thank everyone for their reply's. When narampa put the link over to Amazon, I didn't even think about going there at that time. Went to Amazon for a huge selection of thread sealers and lockers. After much reading and reply's, this one caught my eye. Weld-On Blue Seal Pipe Thread Sealant. What stands this one apart from most of the others is that is made for use on plastics. For use on threaded pipe threads made of ABS,PVC, CPVC, Polypropylene and NYLON. Also can be used on metal. It has PTFE in it like the Permatex 59235 High temp thread sealer that 10Boomer used to seal his sensor in with. The Weld-On has most of the same claims as the Permatex, only it does not say it is a thread locker. The Weld-On is for use with almost all fluids, even steam and deluded acids. Good for temps of -45 to 455 degrees. Liquid pressures up to 10,000 PSI and made to use in high vibration enviorments. So far in my research, this one should be good since the threaded part of the Ford sensor is some kind of plastic and the coolant tank is made of nylon. Just put coolant back in and ran engine up to 179+ degrees. Will report back later and let everyone know what happens. Thanks again.