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Anyone Had Success With Stop-Leak additives?

Ribrickulous

Ribrickulous

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Joined
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Location
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I’m having an issue with an oil leak, or what seems like two oil leaks, from my head gasket.

They’re in the rear corners, right near the oiling holes.

I lost about a quarter of a quart (8oz) over 100 miles riding yesterday (weather was *perfect* up in NY, btw).

I’m going to re-torque the gasket this week, but I’m curious whether anyone’s had success with the additives that are supposed to “swell” the gasket up, should re-torquing not work.


Ed
1972 Honda CL350
 
Not likely re-torquing will work, and I would personally never use any stop-leak in the oil of any engine. This is why I break the Cardinal rule of no sealer on some areas (sparingly, of course)
 
Though no where near enough to lose that much oil, I've got a small weep in the same spot (left side only though) that I'd love to fix without another top end teardown. I was hoping the 500 mile retorque I did last summer would take care of it but it's still there. Like Tom though, I'm not a fan of any stop leak products. I've used a few on a few different old cars in the past with zero results.
 
I doubt any stop leak product would help in your situation.

What I have done with other engines is to use aggressively clean the area of the leak and go well beyond the leak. Dry the area then using a quality RTV like the Right Stuff smear the product over the leak area and beyond. Let thoroughly set up and see how it goes.
 
Did you not install the dowels when you assembled?
it seems like that is a lot of oil and if the dowels are missing then no amount of retorque will help.

What rpm and speeds were you at on your ride?

how do your plugs look? Is oil getting into the combustion chamber too?

that amount of oil loss means your top end isn't getting some of that oil.

Ive never tried those stop leak products, would be worried what else they might plug up, but if you go for it then keep us posted!
 
briandel said:
Though no where near enough to lose that much oil, I've got a small weep in the same spot (left side only though)
Click to expand...

I had the same issue. It was a small weep on the left side only.

I’ve been riding a little more... spirited... recently. Lots of time at the high end of the rev range. 7,500-8,500. I’m wondering if that combined with opening up the oiling transfer piece (crazypj mod) put enough oil pressure against the orifice (I can’t remember, is this in the head or the top of the block?) to force oil out between the gasket surfaces.

Glad it isn’t burning into the combustion chamber at least.

Forgot that there’s a leaky guide on this head, so I think net it’s fair to say I probably lost 6oz.

Going to retorque just to see if I can make a dent and try to troubleshoot this week. No fun carrying a quart of oil everywhere you ride!

Worse comes to worst ill resort to the RTV on the outside of the engine.

And yes, the dowels are in place.


Ed
1972 Honda CL350
 
Ribrickulous said:
I had the same issue. It was a small weep on the left side only.

I’ve been riding a little more... spirited... recently. Lots of time at the high end of the rev range. 7,500-8,500. I’m wondering if that combined with opening up the oiling transfer piece (crazypj mod) put enough oil pressure against the orifice (I can’t remember, is this in the head or the top of the block?) to force oil out between the gasket surfaces.

Glad it isn’t burning into the combustion chamber at least.

Forgot that there’s a leaky guide on this head, so I think net it’s fair to say I probably lost 6oz.

Going to retorque just to see if I can make a dent and try to troubleshoot this week. No fun carrying a quart of oil everywhere you ride!

Worse comes to worst ill resort to the RTV on the outside of the engine.

And yes, the dowels are in place.


Ed
1972 Honda CL350
Click to expand...

The outside RTV is not likely to work on a leak like that. I’ve tried it on my trucks timing cover which only had a mild seep and the “fix” lasted a year. It’s easy to try just giving you a heads up


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RockReef said:
The outside RTV is not likely to work on a leak like that. I’ve tried it on my trucks timing cover which only had a mild seep and the “fix” lasted a year. It’s easy to try just giving you a heads up


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Click to expand...

I’m not holding my breath on it, but it’s one of those “doesn’t hurt to try” things.

I’m going to take it easy on the rpms next time I’m out and see if I lose a similar amount of oil.


Ed
1972 Honda CL350
 
I don't honestly see the rev range making much, if any, difference. Even with PJ's mod these pumps only put out a couple pounds of pressure, maybe three. The seepage you have is similar to what the 450 engine suffers when you use nothing on the head gasket in the area of the flat o-rings and the narrow section front and back of the cam chain tunnel, which is why I sparingly used a little black silicone sealer on my red bike head gasket while it was back apart for the frame re-work.
 
Yeah - hey, it’s a lesson learned.

I did use copper spray on it, but I suppose a thin ring of silicone around the oiling pathway, and probably around the cam chain tunnel is in order for the “pretty” (read: cerakoted) engine.

Edit: side note, when I get around to it, I’m going to post a thread asking for advice on different head gasket types. I didn’t find anything particular on this or the old site.

Ed
1972 Honda CL350
 
Ribrickulous said:
Yeah - hey, it’s a lesson learned.

I did use copper spray on it, but I suppose a thin ring of silicone around the oiling pathway, and probably around the cam chain tunnel is in order for the “pretty” (read: cerakoted) engine.

Edit: side note, when I get around to it, I’m going to post a thread asking for advice on different head gasket types. I didn’t find anything particular on this or the old site.

Ed
1972 Honda CL350
Click to expand...

Well, I'd say that validates my thoughts about copper spray then, clearly it wasn't enough to be the solution. I've always used whatever OEM or aftermarket head gasket available in a decent brand, but with my overbore size recently I'm stuck with whatever the piston supplier offers at S-16 (4mm over)
 
I know it's off track, but I've used copper spray and these super cheap gasket sets off eBay without issues.
I only put a few hundred miles on the engine before retiring it on the side of the house. The frame isn't registered and a couple times I forgot to put the plate on it before leaving the house... asking for trouble.
 
ancientdad said:
Well, I'd say that validates my thoughts about copper spray then, clearly it wasn't enough to be the solution.
Click to expand...

For what it's worth, I haven't written off Copper spray entirely, it helped me with an air leak issue around the carburetor boots. I don't think I've used it anywhere except for those two spots. Haven't needed to yet. Hope I don't ever have to.
 
Sounds like this was a pretty recent rebuild? I typically re-torque the head bolts after the 1st warmup run and after a 100 miles. If needed I may do it again after 500 miles.

I like using Vesrah and Cometic Gaskets with Copper Spray on the gaskets, no silicone. Not shown in this picture is I do use acorn nuts on the two rear outside studs where the oil feeds.
1cf6c7d23d311ca0d45553b297cc8a78.jpg



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Unclear whether it was the retorque or the unfortunate amount of silicon applied to the head gasket (externally... it’s not pretty... none of you will ever see a photo of this engine again), but I lost significantly less oil this time around. High rev highway riding. Can probably attribute it to the valve guide that I know is going.


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MountainGoat said:
Sounds like this was a pretty recent rebuild? I typically re-torque the head bolts after the 1st warmup run and after a 100 miles. If needed I may do it again after 500 miles.

I like using Vesrah and Cometic Gaskets with Copper Spray on the gaskets, no silicone. Not shown in this picture is I do use acorn nuts on the two rear outside studs where the oil feeds.

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Click to expand...

I dig the copper look against the black engine!

I believe I’ve got ~1,000 miles on this head, and a little over 3,000 on the engine overall.

I did retorque after the first 100 and 500 miles following the head replacement. This just popped up oddly seemingly for no reason.

Hopefully it’s behind me.

Looking forward to starting a new build thread!


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Last edited by a moderator:
MountainGoat said:
Sounds like this was a pretty recent rebuild? I typically re-torque the head bolts after the 1st warmup run and after a 100 miles. If needed I may do it again after 500 miles.

I like using Vesrah and Cometic Gaskets with Copper Spray on the gaskets, no silicone. Not shown in this picture is I do use acorn nuts on the two rear outside studs where the oil feeds.

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Click to expand...

Ooh that’s pretty!!


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LongDistanceRider said:
Good looking engine there. I'm afraid you'll be getting an oil leak shortly from the head nuts, oil wicks up the threads. That's why Honda used acorn nuts.
Click to expand...

I think you missed where I stated I used acorn nuts on the 2 back outside studs where the oil feeds from. This build was in August 2020. No oil leaks and 4,000 miles on this build.


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