I've had the cooling system on my 2GM20F torn down, initially just to open ports to the FWP for a new water heater, but eventually I decided to replace all hoses and gaskets, and had the heat exchanger serviced. It's now all back together, but there's an ongoing issue with the mixing elbow.
I've had this boat four years and this was the first time since I've owned it that all this was done. I'm guessing it'd been years before my purchase that any of the hoses or gaskets were done. The mixing elbow inlet from the heat exchanger was nearly blocked. I decided I might as well put in a new one, along with a new union and exhaust elbow, since I couldn't separate the old ones.
All the parts on this job have been straight Yanmar, except for the mixing elbow. I had an aluminum one from ebay I tried first. The union would not pull very far into it, but I tried it anyway. Has some leakage but was able to run the engine long enough to make sure everything else was sealing properly and the water heater was working. I figured I'd take the mixing elbow to a machine shop and have the threads cleaned up.
Being an impatient sort, I ordered a stainless steel mixing elbow from an ebay seller, which also came with a new union. This seller recommended using marine anti-seize compound on the threads (any thoughts on that as a sealant?), which I duly ordered and applied. Same problem as before. Even when putting the mixing elbow in a vise and really leaning into it with a pipe wrench (which I didn't want to do with the aluminum one), I could only get it to thread as shown in the picture below.
So, my question is, should I just bite the bullet and buy a Yanmar mixing elbow, or get a machinist to clean up the threads (which look fine) on the aluminum and stainless units, or what? I realize that pipe threads taper down and that it will be increasingly difficult to tighten, the farther in it gets, but it sure seems I should be getting more purchase than is shown here.
John
I've had this boat four years and this was the first time since I've owned it that all this was done. I'm guessing it'd been years before my purchase that any of the hoses or gaskets were done. The mixing elbow inlet from the heat exchanger was nearly blocked. I decided I might as well put in a new one, along with a new union and exhaust elbow, since I couldn't separate the old ones.
All the parts on this job have been straight Yanmar, except for the mixing elbow. I had an aluminum one from ebay I tried first. The union would not pull very far into it, but I tried it anyway. Has some leakage but was able to run the engine long enough to make sure everything else was sealing properly and the water heater was working. I figured I'd take the mixing elbow to a machine shop and have the threads cleaned up.
Being an impatient sort, I ordered a stainless steel mixing elbow from an ebay seller, which also came with a new union. This seller recommended using marine anti-seize compound on the threads (any thoughts on that as a sealant?), which I duly ordered and applied. Same problem as before. Even when putting the mixing elbow in a vise and really leaning into it with a pipe wrench (which I didn't want to do with the aluminum one), I could only get it to thread as shown in the picture below.
So, my question is, should I just bite the bullet and buy a Yanmar mixing elbow, or get a machinist to clean up the threads (which look fine) on the aluminum and stainless units, or what? I realize that pipe threads taper down and that it will be increasingly difficult to tighten, the farther in it gets, but it sure seems I should be getting more purchase than is shown here.
John
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