Coolant Bleeder screw for 3.4 liter - Tacoma Toyota Cars & Trucks

Chrysler and Dodge 2 7 liter upper water outlet connector replacement...

In 2007 the Buick Lucerne was equipped with 2 engine options. 3.8 Liter OHV V6 and the Northstar 4.6 Liter V8.

Was the cooling system recently opened? What was serviced?

The 3.8 has a 7mm bleeder screw on the top of the thermostat housing. A funnel in the radiator is helpful to bleed the air. You will notice the upper radiator hose curves to a higher elevation than the bleeder screw. Manipulation of the hose by hand may be needed to get the air out. I recommend and use a cooling system funnel to help. It minimizes mess as well. ( https://smile.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY/ref=sr_1_1?ie=UTF8&qid=1488855489&sr=8-1&keywords=lisle+cooling+system+funnel ) There are other brands available as well.

I do not recall if the Northstar V8 has a bleeder on all models, but some do have a similar bleeder screw. Be sure the system is filled initially and manipulate the hoses up and down as well as squeeze them to get air moving. The Northstar water pump is on the back side of the engine driven by the camshaft. The upper hose runs along the front of the engine bay and connects to the radiator at the top on the passenger side of the engine bay.

For both vehicles, fill as much as possible cold. Start and idle. As the temperature increases, I recommend occasionally revving the engine to between 1500 and 2000 RPM to fill heater core and move coolant with a little more force.

The bleeder screw is on the passenger side front of engine. It is a small 1/4" square head bleeder bolt. Turn it counter clockwise making sure coolant level is full. After coolant is coming out then tighten back down.

bleed cooling system, probably there is air trapped in the heater core preventing warm coolant to circulate into the heater core. try this
1 open radiator cap fill coolant and put heater in hi heat
2 start engine and wait until you see the coolant start to circulate
3 squeeze hose several times watching if coolant volume decrease
4 add more coolant and repeat 3 until coolant volume stays same or start overflowing.
5 check if heater giving off warm air or repeat 3 and 4 until warm air blows on heater.
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or find the coolant bleeder screw, do 1 and 2
open bleeder screw until coolant come out, do this several times until no air comes out when opening bleeder screw, fill coolant in radiator.

bad thermostat and coolant maybe low. when a engine gets to hot at certain boiling point it evaporates

drain the coolant
remove the overflow bottle 2-10mm speed nuts
remove the drive belt
remove the water pump pulley(center of the engine and no groves)
4-8mm bolts
remove water pump bolts 4-10mm 3 of the 10mm bolts are on top and the other is under the pulley flange in the center
4-13mm bolts are on the side(they are long bolts they also go through the front cover)
take a hammer and screw driver and tap the pulley flange to break the pump free
clean the old gasket off
and install the new pump
and reassemble
open the bleeder screw on the thermostat housing
fill the rad
close the bleeder screw
start the vehicle and run to operating temperture
check that you have GOOD HEAT(HOT)
hope this helps

Look for a bleeder screw at the highest point of the coolant system, it is usually located on the thermostat housing. Once located open screw with engine off and cool, and pour coolant into the coolant resevoir/ radiator until steady stream of coolant starts to come out of bleeder screw.

run the engine when warm, open bleeder screw slightly. air should come out, wait for steady stream of coolant. Then lock down bleeder screw.

I had the same problem with my 2001 Cadillac Deville, like you I had replaced literally everything thermostat, water pump, radiator, temperature sensor, reservoir and cap, hoses etc....I didnt have any leakage. I was told I had air in my coolant system. After a lot of research and running across the right mechanic I was able to locate the bleeder and remove the air from my lines. No problem since. The bleeder is located on yhe left side of the radiator on the crossover, mines was sideways..Hope this helps someone before they spend money for new head gasket problems..Try this it helped me....