Input and suggestions on changing the Thermostat.

Information and questions on GL1500 Goldwings (1988-2000)
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Posts: 225
Joined: Sun Jun 16, 2013 9:25 am
Location: Selah, Washington
Motorcycle: 1996 GL1500 SE
1989 GL1500 parts bike
1984 GL1200 Aspencade FOR SALE

Input and suggestions on changing the Thermostat.

Post by oldmopars »

So, as I said in another post, when I got my bike I smelled coolant. It would be most noticeable when the bike sat for a week or more and then I took it out. Long story short I found that the thermostat housing was leaking between the plastic neck and aluminum housing. Because this is suck a pain in the neck job to do, I only wanted to do it once. You will have a small mountain of parts that you have to take off to get to the stupid thing, so doing it right the first time is a good plan.
What I found out is that the plastic neck is held down with 3 bolts, M6 I think. When these tighten down it pulls down at these 3 points and over time the housing bows. What I found was that it created small gaps in between the bolts, or high spots.
I am sure I could have ordered a new part from Honda, waited weeks for it to come in and spent a fair amount on it. However, the neck was in perfect condition other than the slight warpage from time.
Here is how I addressed it. I got some 400 grit wet-dry sand paper and our glass top stove. I placed the neck on the sand paper and kept sanding until the whole surface was flat and all traces of warpage was removed. Now I know that the surface is perfectly flat and will seal with the new T-Stat and gasket.
I also purchased a genuine Honda thermostat and gasket. I do not ever want to have to do this job again. Just thought I would share because if you do this job, you will not want to repeat it either. They built the bike around the thermostat.

Posts: 81
Joined: Sun Oct 07, 2018 1:24 pm
Location: Smyrna, ga
Motorcycle: 1994 gl1500 se

Re: Input and suggestions on changing the Thermostat.

Post by Rodzim »

I do this to every chevy 350, 327, 454 and every other engine every time. Its a great idea, i do have a 4"belt sander so it takes me 20 seconds.
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