1720 anti freeze leak

alan40 · Sep 29, 2004

Searched and couldn't find the post. So here is the problem again. It's been stated here that the 20 series tractors have had anti freeze leak at the plug in the side of the engine by the oil and diesel filter. My question is if I take it out and use teflon tape on the thread will that be all right? The part is inexpensive but to get it I have to drive a ways. Any experiance out there. Besides that the 1720 is one heck of a tractor and wouldn't trade it for anything comparable on the market. /forums/images/graemlins/grin.gif

RickB · Sep 29, 2004

A proper job of thread sealing usually does the trick. Teflon tape is what I use.

djradz · Oct 1, 2004

Not sure what will work. On my old 1720 and now on my TC40D, I've had varied success. Last winter I used teflon tape on the 40D, but now it's leaking again. The big problem is the design of the plug. With the right angle nipple on it, you are very limited on where you can end up positioning it. If you can't quite get it to turn all the way such that the fitting is facing somewhat down, then you end up with it back almost a whole turn and then it's not really tight enough.

I've since gone to the plumbing/hardware store and purchased a brass (galv'd would also work) tapped plug and screwed a right-angle radiator type drain valve into it. This way, I will have much more flexibility in how I can position the fittings and still get them turned in good and tight. Plan to install this soon, and then patent it to NH. /forums/images/graemlins/cool.gif

RickB · Oct 1, 2004

The block is tapped British standard pipe, not NPT. The pitch is about one TPI different. Same deal for the oil pressure sender fitting.

alan40 · Oct 2, 2004

Just was at the dealer today to get the part since I broke off the nipple. When asked what they do to get it off they told me they broke off the nipple to make it easier to get out and just replaced the plug. They also recommended the teflon thread goop and not to spare it. British threaded Huh? Now that's interesting.
Thanks for all the input. Of course they didn't have the part in stock. /forums/images/graemlins/frown.gif

RickB · Oct 2, 2004

We have deep sockets with a slot cut to clear the nipple. I think they are 1-1/16 or perhaps 26mm. Carry one on each service truck. Makes it a snap to R&R the fitting.

alan40 · Oct 2, 2004

That's a good idea. A 1 1/16 wrench will work like you say but a 26 mm fits best. May buy one just to have it on hand or find someone to make me a socket like that. I don't have the cutting tool for that kind of job. Boy did that sucker come out hard. Was just a wishing I wouldn't mess it up. Just met my neighbour. He's a mech for John Deere.
Thanks for taking the time for the inputs. /forums/images/graemlins/grin.gif

Boomerbrent · Oct 5, 2004

I replaced the same thing on my NH1925 last fall....built in the fall of 1997. Used a 1 1/16 crow foot wrench that worked well. The flange on the old one broke off while removing the plug, and I was very careful not to break off the new one as the new fitting was threaded on. After cleaning the threads in the engine block, I used a liberal amount of pipe thread dope (plumbers type) and it has held well for the last year.

djradz · Oct 6, 2004

Rick, are you sure about the BPT? The NH plug/fitting appears to be exactly the same as a 3/4"-14TPI NPT fitting. I know in the 3/4" size, BPT and NPT are the same TPI (other sizes are off by .5 to 1 TPI) but even the thread-cut angles appear the same. Supposedly BPT uses a 55 degree angle where NPT uses 60 degrees. I've screwed the NH plug/fitting into standard NPT fittings and it seems to go fine, no binding or misalignment whatsoever. I haven't screwed my brass NPT fitting into the block yet, because I've got so many other projects going, but plan to do it over the winter, and don't want any problems.

RickB · Oct 6, 2004

As far as I know, all the tapered thread fittings on NH compacts are BSP. I could be wrong about this one., but if the TPI are the same for the 3/4" sizes, I will concede to anything. I know my eyes aren't sharp enough to discern a 5 degree difference in thread angles. Let us know how you make out.