Is this normal

[72Z/28]

hi there

Ok guys this is the story, I wanted to get rid of the air pockets from the system, so I started the car with the radiator cap being off as usual. After running the engine for a a few minutes, I noticed that the coolant level started to rise, and some of it began pouring out of the radiator. Once the thermostat opened at 193 degree or so, the coolant level dropped a little bit, so I added some coolant in the radiator and the overflow tank. Then the engine T dropped and stayed around 178 degree or so.

By the way, I don't have any hoses hooked to the heater.

Is this a normal phenomenon that some of the coolant gets pushed out of the radiator right before the thermostat opens when getting air pockets out of the system?

Thanks in advance and appreciate your help guys.

[72Z/28]

Well, it seems like nobody feels like sharing any ideas....

[Z-man]

In my experience, this is very normal. As both coolant and air pockets heat up, they expand - quite a bit. If you have the cap off, it just runs out. Don't let it go too long without a cap because it could start to boil and then it will literally explode out of the radiator (don't ask how I know!).

[72Z/28]

In my experience, this is very normal. As both coolant and air pockets heat up, they expand - quite a bit. If you have the cap off, it just runs out. Don't let it go too long without a cap because it could start to boil and then it will literally explode out of the radiator (don't ask how I know!).

Thanks Z-man, finally i got an answer. I have waited for a few days without any replies from people in this forum..

[180SX_Faktory]

If you can somehow adapt a bleeder type valve on your coolant return hard line, you can achieve the same thing without the coolant blowing out of the radiator neck. That volcano eruption is from the air working itself out.

[TonyL]

yep. most likely the air in the system expanded a lot, and forced the coolant out on its way up.