Do i need to bleed the cooling system after..

[Lucky90]

Its late here on the east coast and i took off the plate on top of the throttle body ,because a little coolant was leaking. Since the plate is at almost the highest point on the motor, did i let air into the system and do i have to go thru the trouble of bleeding the system. Thanks fellas. Oh my zr1 is a 90 if it matters.

[XfireZ51]

Originally Posted by Lucky90

Its late here on the east coast and i took off the plate on top of the throttle body ,because a little coolant was leaking. Since the plate is at almost the highest point on the motor, did i let air into the system and do i have to go thru the trouble of bleeding the system. Thanks fellas. Oh my zr1 is a 90 if it matters.

Let it sit overnight w cap off expansion tank.

[Dynomite]

Originally Posted by Lucky90

Its late here on the east coast and i took off the plate on top of the throttle body ,because a little coolant was leaking. Since the plate is at almost the highest point on the motor, did i let air into the system and do i have to go thru the trouble of bleeding the system. Thanks fellas. Oh my zr1 is a 90 if it matters.

No you do not have to bleed the system if you only let out a bit of coolant to that level of the top of the TB. You have to get the air out if you lowered the coolant level down to the water pump (say about to center of water pump pulley).

If you do drain more coolant..... Post 8 - LT5 Radiator and Initial Coolant Fill Tricks

[Lucky90]

Thanks guys, very informative.

[tomtom72]

There are two things I notice everytime I do my cooling sys service. One is a tip from Marc Haibeck: just make the right side of the car higher than the left. You don't need much, maybe 6" at max. My discovery: if you pour the new coolant in slowly so as not to cover completely the air bleed fitting in the neck, you get most of the air out quickly even with out the right side being higher.

I think the air bleed is the top hose in the neck. I can't remember, but as you fill and get a bit of coolant over it you can see it blowing bubbles. Just don't submerge it and you will pack the system....ofcourse it takes longer to fill.


Tom

[scottfab]

Originally Posted by Lucky90

Its late here on the east coast and i took off the plate on top of the throttle body ,because a little coolant was leaking. Since the plate is at almost the highest point on the motor, did i let air into the system and do i have to go thru the trouble of bleeding the system. Thanks fellas. Oh my zr1 is a 90 if it matters.

Not likely to need burping based on the above but for future reference.
Simplest burping method I've found is to simply remove the small coolant hose the goes to the TB on the driver's side. Remove it right at the TB and prop it pointing straight up. Add coolant slowly until you see a bit come out of the TB coolant connector. Reconnect. You're done. No tilting the car, no waiting a long time for the coolant to settle, no running the car up to temp and wait etc.

[Dynomite]

If you do not let coolant drain below the middle of the water pump...then NO as in your case....but if you drain below that level...then YES.

Trouble is.......no amount of "burping by gravity" will get that air out of the air locked water pump. You can blow (with your own lungs) a pressure of 5 ft of water as a comparison to lifting one side of the ZR1 or LT5 only a few inches higher. You may get lucky and the water pump spin up a little water to start flushing air but usually that is not the case.

The problem is that the Water Pump cavity is above the outlet ports (red line in photo). Air gets stalled above the water line and the pump becomes air locked spinning the air with no water movement.



As you can see in the photo, just raisng the Z or other gravity solutions may get a bit more water in the water pump because you are lifiting one port higher than the other. You may get lucky and after a couple trials get enough air out of the water pump by gravity. The Best Method is to FORCE the air out of the Water Pump.

When I blow into the Drivers Side crossover (disconnected from Drivers Side Injector Housing Manifold and CONNECTED to Passenger Side Injector Housing Manifold) I force water into the passenger side port of the Water Pump and up to the top of the water pump in that narrow path on Passenger Side of Water Pump. That forces air out of the Water Pump through the Drivers Side Port of the Water Pump.

See Details for forcing the Air out of the Water Pump Area in this thread

Post 93 - Filling With Coolant and the Air Locked Water Pump

[tomtom72]

Okay, I know I want to ask this Q: how come all of us don't blow head gaskets after we do a cooling sys flush & refill?

I get what the visual about the pump impeller housing vs the ports' location. What I can't square is that how then can you fill the system with all the hoses connected and just the top tank open?



Tom

[tomtom72]

sorry Lucky90 for the hi-jack! My bad.

Hi Cliff!


Tom

[Dynomite]

Originally Posted by tomtom72

Okay, I know I want to ask this Q: how come all of us don't blow head gaskets after we do a cooling sys flush & refill?
I get what the visual about the pump impeller housing vs the ports' location. What I can't square is that how then can you fill the system with all the hoses connected and just the top tank open?

Tom

You CANT fill the system with all the hoses connected completely with water....you WILL have air in the Water Pump Area. The Water Pump Impeller will catch a little water at the bottom of the water pump and start throwing it around sucking in a bit of fresh water and then throwing that around and pretty soon you have all the air out of the water pump. But not all the time and that is with TB Coolant path NOT blocked.

It is a bit less risky.......Because in your case you have not blocked TB coolant which is an air path back to the coolant tank for air. You still have the issue but with that TB path open and lifting the car a bit you can usually get some water in the water pump area enough to get the water flushing out air on first start.

But as you know.....Marc has his special method for a reason as many of you have run into the air locked water pump but catch it on first start up BEFORE blowing the Head Gasket

ALL of you do not Blow Head Gaskets because you do not let the situation get that far

As an aside...You know Marc makes a TB Heat Bypass Line TB Heat Bypass Line and he installs that rather than totally Blocking TB Coolant like I do. I talked with Marc and he does not Totally Block TB Coolant for a specific reason. Guys will drop coolant and then end up blowing his installed Head Gaskets because of the difficulty of solving the Air Locked Water Pump without that TB coolant path in place.

BUT NOT Cliff as he came up with a fool proof solution to the Air Locked Water Pump (with TB Coolant TOTALLY Capped off) on both a 90' and 91'

Filling With Coolant and the Air Locked Water Pump

As you can see in the photo, just raisng the Z or other gravity solutions may get a bit more water in the water pump because you are lifiting one port higher than the other. You may get lucky and after a couple trials get enough air out of the water pump by gravity. The Best Method is to FORCE the air out of the Water Pump.



Once you get the air out of the Water Pump, Water Flow Dynamics flushes out any remaining air at high spots in the Injector Housing Coolant Manifolds even with TB Coolant Totally BLOCKED.