I recently did a coolant flush on my 1987 D150 318. I noticed the engine block coolant drain plugs are starting to round and the threads are damaged. I’ve looked everywhere I can think, does anyone know where I can order new ones?

Thanks!

Damaged threads

Rounding off

Engine block coolant drain plug

 

should be able to find something at any decent hardware store. i am guessing it is likely just a 1/4" fitting. make sure to check the area where you would find air lines/fitting or plumbing section at the hardware store. i personally wouldn't worry about them damaged threads. it would likely still seal with enough teflon tap but the rounded off bolt head would be main reason i would replace it.

 

Thanks! They look like a 1/2” fitting. I didn’t know if I needed a certain grade of metal fitting to withstand the temperatures. Should I use Teflon tape or could I use anti-seize lubricant? Those things were so tight I was worried I would shear the head off.

 

Its an NPT pipe plug. So, 1/4 or 3/8ths.... any hardware store should have 'em on the shelf. Take your old one in with you, get some to match. Doesn't matter about grade, they are metal, don't deal with high pressures, or temps... (so far as steel is concerned....) Some thread sealer, and yer good to go.

 

i would likely go for the brass plug. they really are not that much then you don't have to worry about steel on steel. i would use teflon tape just to be safe. i would rather just do the job once.

 

I picked up two M14-1.5 oil pan drain plugs from AutoZone. They look like they will work, we will see!

 

Look in the brass fitting bins at any napa auto parts they will have them. They are NPT (national pipe thread) not metric. You need to use Teflon tape or pipe thread sealant on the threads or there is a good chance it will leak.

 

I brought the old plug with me and it fit perfectly in the M14-1.5 female fitting. It wouldn’t fit right in any other fitting, so I’m not sure what’s going on… I bought an assortment of fittings and plugs to be safe so we will see which one works. The plug is so old and damaged it’s hard to tell exactly what size it is anymore.

 

So the metric didn’t work. I bought multiple sizes of plugs, a 1/2 drain plug, a 1/4” pipe fitting, etc. I am 99.9% certain is the right size. I can’t thread anything into the holes, not even the original plugs. I think I’ve just encountered a big problem.

The pipe fitting will go about half way in before I would really have to force it, and I really don’t want to do that. The original plugs were a nightmare to remove. I didn’t think it would be more of a nightmare to reinstall them!

 

Get a pipe tap, and clean up the threads.