Ford Powerstroke Diesel Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
I have an 03 f350. I just replaced the water pump as the old one was leaking. After Changing the pump, I flushed the cooling system several times then switched over to red elc coolant. The problem I'm having now is, the upper radiator hose is full of air, I've driven it several times and the air doesn't come out. I'm wondering if the thermostat may be bad? It doesn't get over 200 when driving.
 

·
Registered
Joined
·
83 Posts
I just replaced radiator, thermostat and upper hose. I had to get temp above 196 before I started feeling heat in the upper hose. However, I would think 200 would be pushing water through it. I've heard the stock thermostat fails open, so that would seem to push coolant through regardless. Hopefully someone can chime in...I'm curious what the solution is.
 
  • Like
Reactions: jokester00

·
Premium Member
Joined
·
3,109 Posts
Did you change the tstat? If so, was it an OEM tstat or a higher temp one? By chance, wonder if you got a 200° tstat and it just hasn't opened yet? If it's an OEM, I'd be pulling and inspecting it.

-jokester
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #4 ·
I never pulled the tstat. Would a bad thermostat cause air trapped, but not overheat?
 

·
Premium Member
Joined
·
3,109 Posts
I never pulled the tstat. Would a bad thermostat cause air trapped, but not overheat?
One wouldn't think so. Trapped air or not, your thermostat should still open at the correct temps. Did you turn your heater on to full blast to make sure you burped that part of the cooling system too?

I'd still be pulling the thermostat and checking it out though, because obviously it's not operating correctly if you really do have 200° ECT and can't feel hot coolant flowing through the upper hose.

-jokester
 
  • Like
Reactions: Weiched

·
Registered
Joined
·
83 Posts
One wouldn't think so. Trapped air or not, your thermostat should still open at the correct temps. Did you turn your heater on to full blast to make sure you burped that part of the cooling system too?

I'd still be pulling the thermostat and checking it out though, because obviously it's not operating correctly if you really do have 200° ECT and can't feel hot coolant flowing through the upper hose.

-jokester
Not my thread, but have a question that may at least contribute to conversation. When getting air out of system, do you run up to temp with degas cap off and heat on? And doesn't coolant run through heater core whether your heater is on or not?
 

·
Premium Member
Joined
·
3,109 Posts
Yes, I suppose coolant does flow through the heater core at all times, however, certain trucks have an inline vacuum valve on the heater core coolant line. If you have your AC set to MAX, then, the valve is commanded closed by a vacuum pulse to keep hot coolant from flowing through the cab.

If I do any sort of cooling system maintenance and introduce the possibility of trapped air, I top off coolant the best I can, turn my heat on all the way (roll your windows down if it's hot outside), and go for a drive. I stop every 5 miles or so while the ECT is warming up and burp the degas bottle by removing the cap slowly (be careful just in case any pressure or coolant comes out) and topping off to the MIN level. Once I've done that 5-6 times and get up to normal temps, I can usually get all the air out of the system. I'll topoff to MIN level one more time when I get home and then wait till engine cools and topoff to final levels over the next couple mornings. That's just how I do it though...

EDIT

I was incorrect about coolant flow. See below from a post by @bismic. Still applicable about getting your heat on when getting the air out of the system.

According to the WSM Section 412-00-6:

For MANUAL climate control:
MAX A/C:

The heater valve (if equipped) is at full vacuum, preventing the flow of hot coolant to the heater core. Blended air temperature is not available.

OFF:The coolant control valve (if equipped) is at full vacuum, preventing the flow of warm coolant to the heater core.

For AUTO climate control:

The heater control valve is automatically controlled by the EATC module in Auto, Panel, Panel/Floor, Floor, Floor/Defrost, Defrost modes based on the temperature settings.

OFF:
The coolant control valve (if equipped) is at full vacuum, preventing the flow of warm coolant to the heater core.

-jokester
 

·
Registered
Joined
·
83 Posts
Yes, I suppose coolant does flow through the heater core at all times, however, certain trucks have an inline vacuum valve on the heater core coolant line. If you have your AC set to MAX, then, the valve is commanded closed by a vacuum pulse to keep hot coolant from flowing through the cab.

If I do any sort of cooling system maintenance and introduce the possibility of trapped air, I top off coolant the best I can, turn my heat on all the way (roll your windows down if it's hot outside), and go for a drive. I stop every 5 miles or so while the ECT is warming up and burp the degas bottle by removing the cap slowly (be careful just in case any pressure or coolant comes out) and topping off to the MIN level. Once I've done that 5-6 times and get up to normal temps, I can usually get all the air out of the system. I'll topoff to MIN level one more time when I get home and then wait till engine cools and topoff to final levels over the next couple mornings. That's just how I do it though...

EDIT

I was incorrect about coolant flow. See below from a post by @bismic. Still applicable about getting your heat on when getting the air out of the system.

According to the WSM Section 412-00-6:

For MANUAL climate control:
MAX A/C:

The heater valve (if equipped) is at full vacuum, preventing the flow of hot coolant to the heater core. Blended air temperature is not available.

OFF:The coolant control valve (if equipped) is at full vacuum, preventing the flow of warm coolant to the heater core.

For AUTO climate control:

The heater control valve is automatically controlled by the EATC module in Auto, Panel, Panel/Floor, Floor, Floor/Defrost, Defrost modes based on the temperature settings.

OFF:
The coolant control valve (if equipped) is at full vacuum, preventing the flow of warm coolant to the heater core.

-jokester
That's good stuff. Thanks!
 

·
Administrator
Joined
·
32,120 Posts
I either use my air lift tool or just drive the truck to get any air out the Degas bottle is made just for this

I think you are making something out of nothing in this case

on this truck turning the heat on does nothing different other than make you hot so just don't put it in max AC if you want the heater to flow

 

·
Registered
Joined
·
7 Posts
Discussion Starter · #10 ·
I either use my air lift tool or just drive the truck to get any air out the Degas bottle is made just for this

I think you are making something out of nothing in this case

on this truck turning the heat on does nothing different other than make you hot so just don't put it in max AC if you want the heater to flow

I think you're right I drove it more and added more coolant, about an inch above the minimum mark, and it seems to have gotten most of the air out.
 
1 - 10 of 10 Posts
Top