What is the safest coolant system sealant

[walterjay]

I have a small coolant leak somewhere. I can smell it but yet to find the problem.

In the meantime I would like to add some sealer into the system. Just a little and not a lot and see what happens. I have done this in years past and it worked well on other vehicles. I don't really like sealer in the coolant so I am asking if there is a relatively safe sealer and what to perhaps avoid.

 

[Nick1994]

Look harder

 

[skyactiv]

Do any parts stores have a cooling system tester kit in their loaner arsenal so you can test it correctly? Look into the Subaru branded coolant stop leak if it's still sold.

 

[zrxkawboy]

See if you can find some Dike by Conklin. It is labeled as a temporary stop leak, because as long as it's in the cooling system it will seal, but as soon as you drain/flush the system, it will be gone. It is sold in pint bottles, and I usually start with a half bottle, which usually does the trick.

 

[Lubener]

I have a small coolant leak somewhere. I can smell it but yet to find the problem.

In the meantime I would like to add some sealer into the system. Just a little and not a lot and see what happens. I have done this in years past and it worked well on other vehicles. I don't really like sealer in the coolant so I am asking if there is a relatively safe sealer and what to perhaps avoid.

I would first pressure test the cooling system then look for leaks. Water pumps are known for hard to find sometimes intermittent leaks. Look on its bottom at the weep hole where they commonly leak. If it is a water pump, no sealer will fix that. If you are dead set on a sealer, I have had some luck in the past with freeze plug and front cover leaks using Barrs.

 

[JohnnyG]

If you decide to use a sealant, and GM thinks Bar's Leak is ok, be sure to install it in the lower rad hose so it goes straight into the block. I wouldn't even put it into the radiator tank myself, and definitely not into the expansion/reservoir tank.

 

[D60]

See if you can find some Dike by Conklin. It is labeled as a temporary stop leak, because as long as it's in the cooling system it will seal, but as soon as you drain/flush the system, it will be gone. It is sold in pint bottles, and I usually start with a half bottle, which usually does the trick.

I had never heard of it but see it online for ~$20 shipped. Thank you!

I've previously used Bar's but it still seems to clog systems and especially heater cores

 

[meep]

There was a time when basically mild doses of Bar’s Leak was oem recipe for vehicles which due to high block porosity always smelled of, and perhaps slowly eeked out, coolant. I had a ‘97 legacy that did this, as well as a ‘97 pathfinder. I think I used a 1/4 dose and it took care of it, and later the OEM adopted this is the official way to send them out.

BUT, if this is a new issue, it depends on perhaps how much you value the vehicle for long term use. You can let it get worse until finding the problem and fixing it, or you can throw some goop in there which will probably prolong the repair but could reduce cooling performance by some small, at the edge, amount. ?? Just my two cents. I don’t like full doses of goop like Bar’s, but for an older vehicle and prolonging what will probably be a big repair, it can have its place.

 

[Chris142]

Pressure test it cold and let it sit. The leak will show up.

 

[Boomer]

Try UV light. Coolant leak should fluoresce a bit.

 

[mjk1967]

If Blue Devil makes a product, might research it. Expensive, but they generally work.

 

[D1dad]

K seal. My nephews VW Passat he’s uses for work was using a cup or so a week and there was no drips that we could find. Of course we didn’t look real hard on a beater with 250k. He added a bottle a few years ago and even did a coolant exchange later on and the leak never returned.