Coolant Drain Valve – 6BTA

[Stephen Oliver]

Hi Guys

Has anyone changed out their coolant drain plug for a small ball valve and then a larger hose tail to a hose for draining easily and cleanly? I’m thinking of using a brass 1/8npt ball valve but unsure if it will take the temps and survive. Just thinking ahead as i’ll be replacing the alternator shortly and was thinking of doing the thermostat at the same time. SB engine is a pig to drain cleanly so i end up dumping it in the bilge and vacuuming out..

Steve

Topic

[Stephen Oliver]

Can anyone confirm this is actually a 1/8npt thread as I originally thought?? I want to do this prior to changing my thermostat…

Steve

[Don Gardner]

By pumping the fluid back in through the drain valve, does that eliminate any air in the system so burping is not necessary? What kind of pump did you use?

[Bob Patterson]

Yes we did on our 3 years ago. Works great. Also pumped out my fluid and pumped it back in.

[Stephen Oliver]

Thanks Russ

Thats exactly where I was talking about.. and what I was envisioning Very helpful.

Steve

[Russ]

Here is a pic of the installation. Got there to take it and realized the valve isn’t actually on the bottom of the heat exchanger, but on the bottom of the pipe below. Better – lower spot to drain more.

[Russ]

The boat is about an hour away and pretty much laid up for winter, and I was just up 2 days ago for a check but I will add taking a pic to my todo list for the next check and get one. Probably some time in the next 2 weeks.

As for draining time, I haven’t had to do it yet. The stbd heat exchanger developed a leak, the aft end piece was separating from the cylinder. I replaced it straight away summer of 2019 and got around to doing the port spring of 2020. I installed the valves during replacement but haven’t needed to drain either yet. Oh crap, now I’ve gone and done it…

1 user thanked author for this post.

Graeme Walker

[Stephen Oliver]

Russ wrote:

I did this, although I don’t remember all the dimensions, but here is what I did:

I used a male/female threaded valve to screw male into the heat exchanger coolant drain hole. I installed it so the lever rests at the 9 o’clock position and has to be moved to the 12 o’clock position to open. I didn’t like the idea of 3 o’clock resting/6 o’clock open, as I was concerned about dropped tools, vibration/gravity, etc. and accidental draining if 6 o’clock was the open position. By using a female thread on the bottom I can screw the original plug back in for added safety.

To drain, I remove the plug and screw in a barbed fitting, slide on the drain hose leading to the collection jug(s), open the valve and smile. No muss, no fuss.

Thanks for this.. i assume as the hole is only 1/8npt its fairly slow to drain but i’ll take that over mess.. its what I was looking to do and like the idea of having the plug and separate hose barb setup.. I’ll see what I can find and report back when I do it..

Steve

[Graeme Walker]

Any chance you have a picture of this arrangement? Thanks.

[Russ]

I did this, although I don’t remember all the dimensions, but here is what I did:

I used a male/female threaded valve to screw male into the heat exchanger coolant drain hole. I installed it so the lever rests at the 9 o’clock position and has to be moved to the 12 o’clock position to open. I didn’t like the idea of 3 o’clock resting/6 o’clock open, as I was concerned about dropped tools, vibration/gravity, etc. and accidental draining if 6 o’clock was the open position. By using a female thread on the bottom I can screw the original plug back in for added safety.

To drain, I remove the plug and screw in a barbed fitting, slide on the drain hose leading to the collection jug(s), open the valve and smile. No muss, no fuss.

1 user thanked author for this post.

Stephen Oliver

[Author]

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