mightyhye

What's the best way to get rid of any air in the cooling system?

I'm overheating just after doing a coolant flush and think this may be the problem.

thanks,

-shawn

LittleRedToyota

park on a hill with the front end higher than the rear...or just jack up the front end. the idea is to get the radiator cap to be higher than any other spot in the cooling system (typically, the highest spot is the heater control valve on the fire wall).

then, with the engine and coolant cold (so you don't burn yourself when removing the radiator cap)...

turn the heater controls to full on. take off the radiator cap and start up the truck...let it run until the engine is fully warmed up. as the coolant circulates, so will the trapped air pockets.

eventually, the air pockets will make their way to the radiator and "burp" out. (be warned, this can make a bit of a mess as coolant burps out.)

keep an eye on the level of the coolant and add coolant as necessary.

once it runs for awhile without burping, put the cap back on. make sure you have adequate coolant in the overflow tank...and keep an eye on that for a few days.

ROMAD

That is the preferred method but I have also had good luck with removing the upper radiator hose (cold engine obviously) from the radiator and pouring in coolant into the block until its full up into the hose. It wont remove all air that way but it seems to make the incline method go a lot faster.

LittleRedToyota

yep, filling the block via the upper radiator hose is a good idea.

another thing to keep in mind (i just noticed your other post about overheating problems)...

some people have had issues with air pockets getting trapped beneath the t-stat...then the t-stat never gets hot enough to open (because it never comes in contact with the hot coolant). this can lead to overheating.

to prevent this, you can drill a small (1/8") hole in the t-stat flange (opposite the jiggle valve). the jiggle valve is supposed to prevent this, but some people have reported that it doesn't always work.

i've never experienced it myself, but i did drill an 1/8" hole in my t-stat flange last time i replaced it just to be safe (since it takes all of 5 minutes and doesn't hurt anything).

mightyhye

thanks guys

-shawn

94x4

1/8" is pretty large comparatively, would a 1/16" be better and perhaps a closer match to the jiggle valve's diameter?

LittleRedToyota

1/16" would prolly be fine...just something to let an air bubble get through if it gets stuck there.

the guy i learned the trick from recommended 1/8"...he rebuilds 22REs in his sleep (and hangs out with engnbldr), so i trust his judgement, so i drilled mine 1/8". haven't had any problems as a result.

takes a weee bit longer to warm up to normal operating temp, but that's it.

jimbo74

www.4crawler.com has a fix for this... dual stage tstat on the 22r series engine

just curious for the people that said they fill the block through the upper hose.... there is a tstat in the way of flow... so how is that possible?

LittleRedToyota

the coolant flows through the hole you drilled in the flange.

actually, i filled it that way before i drilled a hole in the flange, also. i guess it goes through the jiggle valve. it does take awhile...you fill up the hose...wait for the hose to slowly drain...repeat.