Hi, how can I bleed my coolant system on my b18b in a 1992Hb. The water temp is going up and down like a coaster.

Thanks

 

petcock on bottom corner of radiator

 

usually improper coolant levels will cause the engine to idle up and down. so check coolant level. but for the 15-20 fix, change the thermostat. and gasket if that does the trick good, but if it comes back id say you may want to look at a new head gasket cause coolant leaking elsewhere...

 

To answer your question... If you follow the upper radiator hose to the engine you will see a 10mm bolt around a stud with a small hole in it. You loosen this to bleed the air from the system until the coolant flows steadily. Don't forget to replenish the coolant in the overflow recovery bottle.

 

I had air in my coolant after replacing the radiator and as a lazy fix to stop a surging idle I just turn on the car and let it warm up with the radiator cap off. This let bubbles come to the surface and fixed my surging idle.