Head Gasket Issue?

[Celica Man]

Hi guys,

So here’s my concern:

I think I may have a head gasket issue but not sure…

There is no oil in the coolant, there is no coolant in the oil, the car does not overheat – never has. I did one of those chemical sniff tests to see if the color would change and no change.

You would think I do NOT have a head gasket issue right? Well, here’s the mystery: I can smell coolant in the engine bay after running although no drips or leaks can be found. Coolant reservoir is losing coolant but it’s very, very slow – probably have to add a cup of coolant once a month or every 1000 miles.

One more thing: I noticed the other night while the engine was running that the coolant reservoir was bubbling a little…not bubbling over rather just bubbling a tiny bit. I turned the engine off, then waited till it cooled a little. I then started the engine and the coolant in my reservoir tank burped up.

Does that mean there’s combustion gas in my coolant?? Or, is that just from the water pump or maybe air in the cooling system?

Totally stumped here.

Topic

[Agustin Alfonso Cesar Charles]

my bet: air in th coolant and a hose that is actually broken.

[Lorrin Barth]

What vehicle. If it is a Subaru with 150k miles then I say HG is a sure thing. The symptoms kinda point towards a HG but are iffy. How much oil in the coolant?

If this isn’t needed for long road trips I’d suggest driving it some more while watching it and get back to us if symptoms worsen.

[Andrew]

You might have a very small HG failure that is not showing up on the usual tests. I would wait and repeat the tests periodically.

In the meantime, it would be worth pressure testing the cooling system and/or adding some UV leak dye to the radiator. The symptoms you describe could point to a tiny coolant leak that is able to evaporate and is drawing air into the system.

[Celica Man]

Thanks for responding guys. I forgot to mention but i did do a pressure test on the cooling system when it was normal operating temp and no loss of pressure resulted…

There is no oil in the coolant.

I’ll check all my hoses for possible leaks and fittings. Hopefully something positive comes up.

[college man]

If you did a pressure test and nothing dropped. Try changing
your radiator cap.

http://www.ericthecarguy.com/faq/what-to-do-when-your-engine-overheats

http://www.ericthecarguy.com/faq/finding-and-fixing-leaks

[EricTheCarGuy]

Not sure if you did a proper pressure test of the system as you don’t need to warm the vehicle up to do that test.

Additional information on how to check for head gasket failures here.

http://www.ericthecarguy.com/faq/what-to-do-when-your-engine-overheats

Keep us posted on your progress.

[celticbhoy]

My car had a similar issue to yours. I would smell coolant in the engine bay and interior, but would not see any visible leaks and had to refill the coolant every so often. Turned out my heater core had a small leak, but enough so that I would smell it. Even did a pressure test and it maintained pressure. How accessible is yours on your vehicle? Might be worth a shot checking out.

[Lorrin Barth]

Maybe checking the A/C drain would be easier.

[Celica Man]

Hey guys, thanks for offering ideas and the video too. I did cold pressure test to see if that changed anything and it didnt. The pressure had zero loss and its frustrating. Today when getting on the highway I romped on it and within a couple seconds I smelled coolant. My window was down… I did a thorough inspection of the engine bay and no leaks that I could see. I’m going to replace the over flow tank cap…

I have a 2006 pontiac g6 gtp with just over 80k miles. It drives mint, just has a lingering coolant smell…so annoying.

[Lorrin Barth]

Look around on the radiator where the tank meets the core. There’s a gasket in the crimped area and sometimes as it starts to fail it just slowly oozes coolant at a very slow rate. Often, when this is happening, what you will see is dried coolant in this area. However, the radiator fans will bring the antifreeze smell to your nose.

[Celica Man]

Ok, I’ll look at that. I didn’t think to look there, thanks!

[John Hugon]

If it’s a 3.5/3.9 L V-6 maybe a lower intake gasket, crossover pipe gaskets for the (rear side) cylinder head and check the left rear side of the cylinder head gasket against the firewall. You’ll have to use an inspection mirror…any moist look between the engine block and cylinder head is the problem.

Follow Eric’s coolant system diagnosis..you will find your issue.

[Celica Man]

It’s the 3.9 engine. The lower intake gasket was replaced last month.

I think the problem may be solved. I noticed a couple drips slowly forming at the overflow tube off the overflow tank after I turned the car off. I thought that was odd so I squeezed the lower tube (off the head I think) and the overflow hose forced out coolant (a couple drops).

I then inspected the cap and noticed the seal was cracked. That’s got to be my problem right?

I ordered a new coolant overflow tank cap…hoping that solves the problem.

Question is: WHY didn’t coolant drip out with 15 pounds of pressure in the system during the pressure test?

[Its me]

As stated, it may be a heater core leak…. Try turning the fan on high and turning up the defrost on high heat as well for 10-20 minutes… Observe if there is any oily/greasy-like fogging on the windshield and/or if the coolant smell is more pronounced…

-Karl

[Andrew]

Pressure testers deliver pressure directly into the radiator and don’t let it escape into the overflow tube. The coolant overflow tank is not part of the pressurised system.

[Author]

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