airlocked waterpump
Thread Starter
|
Senior User
Joined: Jan 2008
Posts: 219
Likes: 0
From: Southern IL
airlocked waterpump
I was told if i rev my 351 up and the level of the coolant goes down then you still have air in your block. Well my coolant level goes down when i rev it up. I was wondering if this was true? It it is how is the best way to get the air out of my system? thanks
Postmaster
Joined: Oct 2008
Posts: 3,026
Likes: 0
From: Renton, WA
Ya know I've never really thought about why the coolant level goes down when the engine is revved but that kinda makes sense. I can however make some good suggestions on how to get all the air out. Two things I always do is to make sure there is some kind of hole in the thermostat to let air out if there isn't one there drill one. Second leave/take the raidiator hose off the thermostat housing until coolant comes out the thermostat housing while filling the raidiator. The most important area of the motor to make sure there's no air is under the thermostat. If there's air under the thermostat it won't open, the air won't come out, and the engine will overheat.
It seems to me there are areas of the block and head that at least while the truck is level will have air pockets. (the top corners of the block, above the passageways to the head) These air pockets wouldn't hurt anything and will work there way out as you drive.
The chevy 400 small block has extra holes in the deck serface and head to allow air out because on these engines there's no space between the cylinders in the block. There actually comonly referd to as steam holes. Thought that might be interesting.
It seems to me there are areas of the block and head that at least while the truck is level will have air pockets. (the top corners of the block, above the passageways to the head) These air pockets wouldn't hurt anything and will work there way out as you drive.
The chevy 400 small block has extra holes in the deck serface and head to allow air out because on these engines there's no space between the cylinders in the block. There actually comonly referd to as steam holes. Thought that might be interesting.
Laughing Gas
Joined: Oct 2001
Posts: 957
Likes: 3
From: Winchendon MA
The level in the rad drops yes but not in the block. The block sees the hi presure side of the pump and it the T-stats job to regulat the flow and presure the block sees. You want presure to keep localized boiling to a minimum every 1 psi = 7 deg F of boil protection. Most vehicals have a bleed line from the factory it's the heater core. coolant is allways flowing through it.
Just keep the coolant overflow tank between the cold and hot marks any air will make its way out at some point on a long drive and when the truck cools down it will suck in coolant.
44
Just keep the coolant overflow tank between the cold and hot marks any air will make its way out at some point on a long drive and when the truck cools down it will suck in coolant.
44
Postmaster
Joined: Oct 2008
Posts: 3,026
Likes: 0
From: Renton, WA
The level in the rad drops yes but not in the block. The block sees the hi presure side of the pump and it the T-stats job to regulat the flow and presure the block sees. You want presure to keep localized boiling to a minimum every 1 psi = 7 deg F of boil protection. Most vehicals have a bleed line from the factory it's the heater core. coolant is allways flowing through it.
Just keep the coolant overflow tank between the cold and hot marks any air will make its way out at some point on a long drive and when the truck cools down it will suck in coolant.
Just keep the coolant overflow tank between the cold and hot marks any air will make its way out at some point on a long drive and when the truck cools down it will suck in coolant.
There is a coolant bypass designed into the motor, yes the heater does the same thing but it is not always open. The coolant bypass on a 351 is the short pain in the a** hose that goes between the water pump and the intake manifold. This bypass is there to prevent "cold shock" making sure that if the coolant in the raidiator is very cold and the motor hot, that when the thermostat opens that cold water is heated a bit so it doesn't cold shock the motor.
Post Fiend
Joined: May 2004
Posts: 11,289
Likes: 6
From: Lakewood, Ohio
from ford service manual:
fill the coolant system, disconnect the heater outlet hose at the water pump to bleed or release trapped air in the system. when the coolant begins to escape, connect the heater outlet hose.
fill the coolant system, disconnect the heater outlet hose at the water pump to bleed or release trapped air in the system. when the coolant begins to escape, connect the heater outlet hose.
Postmaster
Joined: Oct 2008
Posts: 3,026
Likes: 0
From: Renton, WA
That's nice but the heater hose nipple on the water pump is to low. There's lots more air left above it.
Trending Topics
Post Fiend
Joined: May 2004
Posts: 11,289
Likes: 6
From: Lakewood, Ohio
maybe you should write to the ford engineers so they can revise the service manual.
i am just relating how it is supposed to be done per ford recommendations.
i am just relating how it is supposed to be done per ford recommendations.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
the water pump isn't really a pump
The coolant bypass might ease thermal shock as you say, but it also is to allow coolant flow through the engine to heat the water in the block more uniformly so localized boiling does not occur waiting for hot water to reach and open the thermostat. The bypass may also serve to reduce or eliminate any effects from dead head on the water pump.
I'm still confused as to why a water pump isn't a pump. The water can't just circulate at tens of gallons per minute on its own. The water pump might not create much of a pressure head, but it does generate a lot of flow. The heater core in these trucks always circulates coolant.
As for bleeding the system, I always fill the radiator just less than full, then start the engine with the radiator cap removed and let it run. When the thermostat first opens it may puke out some coolant, but it will drop pretty quickly after it fully opens. Fill the radiator and let the thermostat cycle open again and that should pretty much take care of bleeding the system.
Thread Starter
|
Senior User
Joined: Jan 2008
Posts: 219
Likes: 0
From: Southern IL
tonight i will work on getting the air out of the system the way you guys recommend and drive it to work tommorrow and let you guys know what the verdict is. It will be tommorrow afternoon.
Laughing Gas
Joined: Oct 2001
Posts: 957
Likes: 3
From: Winchendon MA
it is a pump it called a Volute type centrifugal pump. One of the earliest types of pumps.
Pump don't real create pressure this is true they create flow the resistance to flow is pressure the two are inversely proportional.
Elder User
Joined: Aug 2007
Posts: 502
Likes: 0
