Thermostat gasket cut too small

[The motor guy]

I had a buddy change out the thermostat gasket on my boat and when he cut out the gasket he cut the inside hole slightly smaller, like maybe 1/4'' smaller. It's not interfering with the thermostat operating, but it does overlap it a tad. I'm irritated he didn't take more time to cut it out better. I was going to take the boat out today, but decided not too cause i'm paranoid that that portion of the gasket will break off and get into the coolant system. I'm like really?? and he's like it's fine it's fine I do these all the time. He got it to stop leaking better than it ever has, so is it okay temporarily for a couple boat rides until I fix it again using rtv and Teflon sealant on the bolts like people here suggested?

 

[The motor guy]

I know. How dumb can you get huh?

 

[Nick1994]

It overlaps on the side where the thermostat meets the engine, or where it meets the housing?

If the housing side, I'd just keep an eye on it. Being a boat on the water, if it started leaking, it's not going to overheat, right? Since it won't ever run out of coolant. I could be wrong, I don't know boats lol.

 

[rubberchicken]

What boat engine ? If its a GM based engine, make sure you use the gasket with the brass eyes- they are required for proper corrosion protection and continuity of the thermostat sender.

 

[The motor guy]

Yes it is covering the bypass hole, but I don't think it would block the flow.

 

[Chris142]

Run it. You are way overthinking it. The extra gasket wont go anywhere. Years ago we bought thermostats that came with a universal gasket. It hung out in several places.

 

[nobb]

If you're OCD like most people here, just change it for the peace of mind. Better to do it sooner too because as that gasket hardens from the heat cycles it'll be more work to change out later (I hate scraping gaskets).

Also next time you do it, you shouldn't need RTV. Almost every gasket maker recommends a clean surface with the gasket installed dry. RTV just increases the chance that chunks will break off and enter the cooling system.

 

[eljefino]

If it's been leaking you have a not-flat surface. Corrosion?

As long as you're seeking out universal gasket material, I'd find something a little more rubbery and spongy.

 

[The motor guy]

I think it leaks through the bolts holes. It goes through to the coolant. So really I just need to add some thread sealant.

 

[Lubener]

Originally Posted by motor_oil_madman
I had a buddy change out the thermostat gasket on my boat and when he cut out the gasket he cut the inside hole slightly smaller, like maybe 1/4'' smaller. It's not interfering with the thermostat operating, but it does overlap it a tad. I'm irritated he didn't take more time to cut it out better. I was going to take the boat out today, but decided not too cause i'm paranoid that that portion of the gasket will break off and get into the coolant system. I'm like really?? and he's like it's fine it's fine I do these all the time. He got it to stop leaking better than it ever has, so is it okay temporarily for a couple boat rides until I fix it again using rtv and Teflon sealant on the bolts like people here suggested?

Giiligan did the same thing before they set out on their last cruise.