Coolant system - Pressure Test Question

[c_m_25]

Will somebody explain to me how a pressure test works for the coolant system? For instance, would you be able to detect a leak in the head gasket during the test since the thermostat is closed? Will the test see a small leak in the heater core?

I’m still dealing with an issue with a coolant smell in the engine bay when I shut it off. I have had it in twice now and they have performed 2 overnight pressure tests and they were both negative for a leak. I’m getting really frustrated with this issue as i am pretty sure that you’re not supposed to be smelling coolant like this. Thanks

 

[c_m_25]

Will somebody explain to me how a pressure test works for the coolant system? For instance, would you be able to detect a leak in the head gasket during the test since the thermostat is closed? Will the test see a small leak in the heater core?

I’m still dealing with an issue with a coolant smell in the engine bay when I shut it off. I have had it in twice now and they have performed 2 overnight pressure tests and they were both negative for a leak. I’m getting really frustrated with this issue as i am pretty sure that you’re not supposed to be smelling coolant like this. Thanks

One final question. If there is a leak in the heater core, will the smell go away when I stop using the heater?

Btw, I’m getting maybe a very faint smell in the cabin but it’s hard to tell if my brain is playing tricks on me.

 

[Muskiez]

I have the same smell and the level on the dipstick has slowly went down. No apparent leaks that I can find either. Mine goes in Monday so we will see if they can come up with something

 

[Richard320]

A pressure test puts the system under as much pressure as the cap normally provides, but it's not hot or running, which gives you the ability to poke around in places you couldn't if you had belts and such moving. You can leave it on for hours, even overnight, and see if it holds. Tiny leaks won't evaporate because it isn't hot.

Someone might be able to get a look inside the heater case through the AC drain or the cabin filter door. Maybe even with a borescope.

A leaky head gasket may or may not show. An oil analysis should detect it. It could be leaking into the oil, not into the cylinder.

I've smelled coolant once in a while after shutting off the truck after a good long drive. I've never been able to spot a leak and it doesn't seem to be leaking anywhere. Could be that it bubbled vigorously in the overflow tank and released a lot of smell. Kinda like a barista frothing milk.

 

[c_m_25]

What do you mean when you say “tiny leaks won’t evaporite because it isn’t hot?”

Does that mean that a small leak won’t show if the engine is cold?

 

[Richard320]

What do you mean when you say “tiny leaks won’t evaporite because it isn’t hot?”

Does that mean that a small leak won’t show if the engine is cold?

If coolant is oozing from somewhere and it's really hot, it's going to evaporate and leave a crust behind. So you might see the crust but not see exactly where it's coming from. But if it's cold and leaking, you might be able to see where it's originating.