Coolant Smell

[nightowl]

2003 silverado. I started smelling coolant in the cab last winter when the heat was on. No smell this summer with a/c or vent. A couple weeks ago I drove it on a cool morning and turned the heat up a little and smelled it. I assume it is the heater core. The carpet is dry and the windows don't fog up or oily. I just did a pressure test and no leaks and the pressure held at 15psi. Any ideas?

[richard wysong]

probably a very small leak that evaporates before it can puddle. Check the connections to the hoses at the firewall and if they aren't seeping I would try a half bottle of Bars leaks sealer

[diyer2]

I would never use Bars leak in my cooling system. 

[richard wysong]

Why? it was used by Gm for years when they do the factory fill to insure no seepage. The best way to get the sealer to the heater would be to disconnect the hoses , blow the coolant out of the core and use the red powder sealant that radiator repair shops use by blowing it into the heater core, you could also use the powdered aluminum parts store sealer but that's a LOT of work and if it's that small a leak then a small amount of Bars leaks or an equivilant should stop it

[nightowl]

I did use bars leak last winter and it did not help.

[diyer2]

My personal preference. 

[richard wysong]

Sealer usually won't work if it's a tank seam leak because of the expansion/contraction dislodges it but I would expect a larger leak if the tank or pipe connections were leaking. I would try blowing some powdered sealer into the heater before replacing the heater core. It is NOT an easy job to change the core. make sure you blow it into the inlet side of the heater if you try it

[nightowl]

4 minutes ago, richard wysong said:

Sealer usually won't work if it's a tank seam leak because of the expansion/contraction dislodges it but I would expect a larger leak if the tank or pipe connections were leaking. I would try blowing some powdered sealer into the heater before replacing the heater core. It is NOT an easy job to change the core. make sure you blow it into the inlet side of the heater if you try it

I'll check into that. I just can't understand when I did a pressure test it held at 15psi for a few hours.

[richard wysong]

It must be a VERY small leak, if you didn't smell it you wouldn't even know, I'm surprised the sealer didn't stop it. It probably has an aluminum core which usually last the life of the truck without problems as long as you're careful when messing with the hose connections

[nightowl]

3 hours ago, richard wysong said:

I would try blowing some powdered sealer into the heater before replacing the heater core. It is NOT an easy job to change the core. make sure you blow it into the inlet side of the heater if you try it

How do you blow powdered sealer into the heater core? Googled it but only came up with adding it to your coolant and letting it circulate.

[richard wysong]

Disconnect both heater hoses at the firewall, using compressed air blow as much coolant as possible from the heater core then take a piece of heater hose stick it on the inlet pipe and dump a little sealer in it, give it a couple puffs of compressed air and you may or may not see the dust come out the outlet depending on how much coolant is still in the core. When I worked at the radiator shop we used a red powdered sealant on Questionable repairs, It might have been called Red Devil but I really don't remember. We always just dumped a little in and gave it a blast of air to distribute it thru the core but it is a lot easier to do with the thing out laying on a bench

[customboss]

I am with Richard on this. 

 

I raced cars for GM factory Olds IMSA road racing  and outta factory we had aluminum coolant components leak.  GM coolant tabs ( organic non metallic stuff) work temporarily and were added at factory on many Cadillac, Olds, Buick engines.  Non corrosive but seals asperities factory doesn't want to deal with. 

 

In junk or dollar restricted cars for customers who don't care,  use the metallic sealers but realize they can cause secondary corrosions and are usually temporary too. 

 

Red Devil chemicals did make some kind of dry and liquid solder that is effective but it will let go eventually, too.  

 

Repair/replace the problem if you can.  

 

 

 

 

[diyer2]

Repair/replace the problem if you can.  

The right way!