Small Coolant Leak

[sgtsandman]

We try to learn from other’s personal experience so as to not experience the same.

Stop leak clogs up more than the leak and will cause problems down the road. In the end, it is your truck and your money. It’s up to you what you do from here.

 

[Rearanger]

So I checked the FSM on the front cover and WP. There are two bolts on the front cover that require bolt sealant which coincide with the leaking area. The WP also requires sealant on some bolts but doing that requires removing the front cover - what I'm trying to avoid.

I'll monitor for now and if it continues to leak then I'll pull those two bolts and re-apply sealant. Thanks for heads up as I did not consider this.

 

[Guanfy]

So I checked the FSM on the front cover and WP. There are two bolts on the front cover that require bolt sealant which coincide with the leaking area. The WP also requires sealant on some bolts but doing that requires removing the front cover - what I'm trying to avoid.

I'll monitor for now and if it continues to leak then I'll pull those two bolts and re-apply sealant. Thanks for heads up as I did not consider this.

To add a +1 to the comments about using stop leak... it does work. However you run a very nonzero risk of clogging other small passages in your cooling jacket in the block when you use products of that nature. Most of them work by reacting with oxygen and solidifying at that point, in theory stopping your leak. But they can also clog passages in the block or in the smaller passages in the radiator or heater core. If you use it and there is a clog and repairs are required, then you have extra work to do to make sure you flush all the stop leak product out of your cooling system so it won't accidentally clog up new parts.

To sum it up I would only use stop leak on a cooling system that you fully intend to replace someday soon and you are trying to keep the existing one going just a little bit longer.

 

[Rearanger]

To add a +1 to the comments about using stop leak... it does work. However you run a very nonzero risk of clogging other small passages in your cooling jacket in the block when you use products of that nature. Most of them work by reacting with oxygen and solidifying at that point, in theory stopping your leak.

I emailed Bars Leaks with the question about oxygen. Here's the answer I got:

"For the HDC Tablet product oxygen is not required to seal the leak like sodium silicates for example. That being said, the product will seal the leak regardless of the presence of oxygen or not, but after it is exposed to air, it will further harden after stopping the leak to create a more permanent fix."

They also stated in a previous email that the product shrinks 15% when immersed in coolant.

I think air is the only reactant. As long as the cooling system does not see air and the passages are larger than the particles it should not clog other parts of the system.

That being said, it is not my first go to and I think your idea about bolt seal leakage is very much a probable, also given the small amount of leakage. As I said I will monitor and then try resealing the two bolts mentioned.

 

[Rearanger]

Question. Have you tried to wrap the bolts you torqued in teflon tape? Some of those bolts do also seal so if they are not wrapped or covered in pipe dope they can cause a leak.

When I did the cover/WP I used Permatex High Performance Thread sealant as per the FSM, even doing more bolts than it spec's as it was hard to tell which breached the water passage.. I have used Permatex many times before with unfailing results. I did not consider T tape. You may be right that it is a bolt thread leaking and not a gasket - so maybe removing a couple bolts in the area of the leak and redoing them with T tape. That I will seriously consider. Thanks.

So this turned out the be the best advice, at least initially. I removed the splash shield to give better access to the leak and found it was coming from a water pump bolt higher up than I thought. I removed the bolt and found rust on it and clear indication this was the leak location. Cleaned up the bolt, applied new thread sealer and waited. It was OK for a few days but then started slow leaking as before.

I decided to use the Bar's Leak tablets HDC. From some internet research of actual use and GM recommending (1 tab per 7 quarts) using less than that prescribed by Bar's Leaks, I used 3 tablets instead of 6-7. Followed package directions and after a 20 minute drive and cool down over night the leak has sealed. Several days of driving and cool down shows continued leak stoppage.

There has been no indication of rad or heater core blockage. I get full cabin heat and engine running temps have not changed (digital heat gauge). I plan on now flushing the cooling system as Bar's says that will not affect the seal.

I'll just have to see if this holds and if I get any adverse outcomes. I cannot comment on any other stop leak and think it's important to use this in a clean or at least flushed system to prevent possible internal blockage, although I've seen no general stories of this actually happening.

I do not think this should be the accepted overall fix, but in my case it has saved me a ton of work. I'll live with it and report back with my continued actual experience.