2002 Nissan Sentra bubble in cooling system

KGILFILEN

MEMBER
2002 NISSAN SENTRA
4 CYL
FWD
AUTOMATIC
79,000 MILES

My sentra is blowing cold air from the heater. It was diagnosed earlier with a blown head gasket, which I repaired. I then changed the radiator, which wasn't holding pressure.

Now the system pressurizes, and isn't losing coolant, but still blows cold air from the heater. I've tried parking it on a hill and reving the engine for 30 minutes, as advised by a Nissan shop manager (online). It blows hot air with the front wheels raised, but returns to cold when back on the flat.

I've followed the coolant fill/bleed procedure in the owner manual.

I'm told by mechanics that this model is particularly difficult to clear bubbles from the coolant. I am almost out of hair, and grasping for any help I can find.

The car runs fine now, doesn't overheat. But it's my wife's car and it is still January in Colorado. She at least needs to have enough hot air to warm the windshield.

TIA.

2 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

Thank you for the donation,

These can be hard to bleed all the air out off, what I have found helps is that I disconnect the heater hoses and back fill the core, refit the inlet hose with a clamp and fit the other hose with clamp on hose but away from the end of the hose, run the engine and using a cooling system pressure tester build up about 10 PSI with the engine warming up work the hose ton a position that water can start to escape, but just a trickle, allow this to bleed the system and then replace clamp, you may need to do this a few time and use good gloves if it starts to get to hot so you wont scold your self. Start here.

Mark (mhpautos)