Leaky head gasket or air pocket?

Maintenance/Repairs
1

I’ve been having trouble with the cooling system of my 2005 Kia Sedona (about 90,000 miles) and a couple months back I had the system flushed, coolant added and thermostat replace. Not long after this the overheating started up again. After the first five minutes of driving, the thermostat starts creeping up above the half way mark and within about ten minutes it hits the H. My vents also don’t blow heat. After ten minutes the heat SOMETIMES suddenly kicks in after the needle hits H, but it’s kind of inconsistent and sometimes I get no heat even after hitting H and sometimes I get a little heat and then it goes away. I only drive it 15 minutes each way so am not sure what would happen if I kept driving.

Anyway, I took it back to the shop and they did a pressure test and said they thought it was a leaky head gasket and that they couldn’t do the repair and I should take it to a Kia dealer. I picked it up and on my way home I noticed I was getting heat from the vents immediately and the thermostat stayed at the halfway mark. No overheating. Is it possible they are wrong and the pressure test knocked some air out of the system and that the test actually fixed the problem? Can a pressure test give a false result?

Anyone with any experience or insight here? Thanks in advance!

2
Is it possible they are wrong and the pressure test knocked some air out of the system and that the test actually fixed the problem? Can a pressure test give a false result?

Yes, it’s possible it was fixed…have you lived a righteous life?

Yes, a pressure test can give a false result if the head gasket leak is very small.

You’ll know in a few weeks (or days).

3

What kind of shop couldn’t fix a head gasket? The only way the pressure test could have fixed anything is if they refilled your low coolant level afterward.
When you have the symptoms you describe the first thing you should do is take the radiator cap off the COLD engine and check the coolant level. It is supposed to be completely full. Keep doing this until it stays completely full.
If after three times, it still doesn’t stay full, take it to a competent shop to diagnose.

4

Your heater is working because they refilled your cooling system, whether it remains full is uncertain.

You shouldn’t drive the vehicle when the cooling system is low, this is how head gasket problems develop. Check the coolant level daily before you drive (cold) until you can be sure there is no coolant loss.