My CRV Gen2 K20A A/T builds air pressure in the cooling system no matter how many times it is properly "burped". The radiator, cap, hoses, thermostat, pump have all been checked and replaced.

Even after sitting overnight, when i open the rad cap, the coolant rushes and blows out of the reservoir. The upper and lower radiator hoses have also popped out during long drives.

Temp does not rise long as i keep the coolant levels in check. No signs of coolant in oil. No white smoke. Could this be a head gasket issue?

 

Classic sign of a head gasket leak, have it checked for HC in the coolant, but the only other part that could possibly cause a mad rush of coolant would be no thermostat, but since you have air, thats a whole nother ball of wax.

One thing that helps on some cars, mostly Nissans, is to raise the front of the vehicle off the ground to force the radiator to be much higher than the rest of the system. The same can be accomplished by using a remote funnel that you can find at a lot of parts stores.

I'm kinda betting head gasket. Put a pressure tester on it as well and tell us how much pressure you get on a cold start.

 

Headgasket or cracked sleave......

 

After replacing every external part that could cause that pressure, im now ready to do a headgasket change. Hope its not a cracked sleeve tho

 

It could also be your head. Inspect it very carefully.
Is this your first head gasket change?

 

You need to ensure the decks are still straight when you pull them off. I should have asked sooner, pull the spark plugs and examine them, see which one, or two, are the odd ducks. At least when you tear it apart you will know where to concentrate your efforts.

 

I am not doing it myself. I had 2 shops check it and they both did not want to pull out the cylinder head that fast. They were not 100% sure it is a head gasket issue because the car does not overheat at all. No traces of oil in the coolant/exhaust. Cant figure out the pressure buildup.

 

Did they perform a leak down test? If not why not?

 

Head gasket gets my vote....

 

Whats the oil look like hopefully it doesn't mix.

 

For 20 bucks you can get a compression tester and test it yourself. Just pull the ecu fuse and unplug the main relay. It's normal for coolant to come out of the radiator slightly when you open the cap as there is always a small amount of pressure in the system. The point of the cap is to help regulate the air. I'm wondering if maybe you have the wrong cap for your car and it's not allowing pressure to bleed out. I'm also wondering why you're losing coolant in the first place.

 

If there is air getting into the cooling system then it will overheat. A leakdown test or HC test is a step in the right direction at this point. They will point at a faulty headgasket. Pressure testing the cooling system is also a good idea if the other test passes.

 

sounds like head gasket.
hydro carbon test
smog machine probe for hydro carbons
compression test
leak down test

 

Can anyone tell me what bar my gen 1 crv with a B20z engine. Shoul it be 1.1 bar or .9. B20z. No modification what so ever done with the engine or any of the car.