They aren't. As I mentioned earlier in the thread, they are BSPP (British Standard Pipe Parallel) thread, which is different from NPT, BSPT and metric.

Again, for anyone in a non-emergency situation, order one from Rovahfarm, along with some RTC3511 hub seals to spread the shipping costs. A plug and 5 or 6 seals would be about $5 or $6 shipping USPS flat rate.

 

Thank you, hopefully she'll keep on going for another 100k. It does have the R380. I just posted a thread on the original R380 that was rebuilt and then blown up. I still have the original but its been sitting and rusted. All it needs is a fifth gear and its counter-shaft counter part. And then I'll have a brand new "Extra" R380 .

 

mine had a pipe fitting like that when I bought it it was wrapped in teflon tape and leaked, instaled the plastic one with an oring and no more leak there

 

I got lucky with mine, Broke when I had my truck in the shop i was working at for ac work, replaced the tank while it was inside and while removing to bleed, it snapped. one guy in the shop had one spare plug and it happened to be the right one. not sure what it was from, drain plug from something, but 2 years later it works and seals no problem, and it's been in and out several times.

 

I have the RovahFarm brass plug along with the rubber O-ring. Is the O-ring also required for the brass plug or is that only for the plastic plug?

When I try to use the O-ring it bulges out from under the plug. For the time being, I removed the O-ring and wrapped a little thread tape on the brass plug.

 

There is no groove on the underside of the head for the o-ring to drop into on the Rovahfarm brass plug. I used these for my Diff plugs on my D2 and just added a little RVT type sealant around the base of the plug on the underside of the head. Not sure what may be your best bet when using it on the cooling system on the D1. I would say the thread tape may be a good way to go, but no sure. I will let some D1 guys jump in on that.

 

It's BSPP thread so they don't seal by the threads. Use the o-ring and just don't tighten it more than you need to. You may need to experiment some.

I didn't know the rovahfarm plugs didn't have the recess. I guess that's thy they are cheaper.
The ones I use have the recess for the o-ring, but I had to sell them for about $13 so didn't bother anymore because of the cheaper ones available.

 

Do you have anymore of the better ones for sale?

 

Just found this: $2.99 and it looks to have the O-ring groove

FILL PLUG RADIATOR TDI,V8 1989 ON BRASS, PLC997, ERR4686 - Land Rover Parts | Rovers North

 

I didn't have issues with the o-ring bulging out. I used the o-ring with the plug and have not had any issues.