2005 F250 5.4 Checked everything still blowing cold air
Thread Starter
|
8th Gear
Joined: Aug 2007
Posts: 8
Likes: 0
2005 F250 5.4 Checked everything still blowing cold air
Hi everyone,
With no sign of a warm-up, I finally had a free day to tear into my f250 work truck to find out why there is no heat.
Just blows cold air
Pulled the HVAC blend door actuator in the glove box, and shaft is rotating when the **** is turned.
drained and flushed the radiator twice.
Replaced the thermostat
New antifreeze at the full line.
The only time it started to blow some heat was when the thermostat was out. (I pulled the thermostat out after I observed the upper hose hot and the lower hose cold)
I did not expect the heat to return to cold after I put a new thermostat back in.
There have been no signs of a water pump failure.
There has never been a sign of the engine temp getting out of normal range.
The heater core inlet temp is warmer than the outlet temp.
Looking for other tests I can run.
I do not see an easy way to hook a hose directly to the core at the firewall.
If no suggestions, I would like to know the downside to just running without a thermostat until I get warmer temps outside.
At least then I got some warm air.
thank you
.
With no sign of a warm-up, I finally had a free day to tear into my f250 work truck to find out why there is no heat.
Just blows cold air
Pulled the HVAC blend door actuator in the glove box, and shaft is rotating when the **** is turned.
drained and flushed the radiator twice.
Replaced the thermostat
New antifreeze at the full line.
The only time it started to blow some heat was when the thermostat was out. (I pulled the thermostat out after I observed the upper hose hot and the lower hose cold)
I did not expect the heat to return to cold after I put a new thermostat back in.
There have been no signs of a water pump failure.
There has never been a sign of the engine temp getting out of normal range.
The heater core inlet temp is warmer than the outlet temp.
Looking for other tests I can run.
I do not see an easy way to hook a hose directly to the core at the firewall.
If no suggestions, I would like to know the downside to just running without a thermostat until I get warmer temps outside.
At least then I got some warm air.
thank you
.
Last edited by mgolin; Jan 23, 2022 at 04:54 PM.
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
The heater core inlet temp is warmer than the outlet temp.
Running without a 'stat pretty much guarantees that the heat won't work right, if at all. Put a new Motorcraft thermostat in there, fill and burp the system and recheck.
Thread Starter
|
8th Gear
Joined: Aug 2007
Posts: 8
Likes: 0
I do not believe my truck has the HVAC Heater Control bypass Valve. The heater hose runs directly from the water pump to the firewall.
During warmup, Temp gauge always moves to the normal position. I did not see the new Thermosate opening today but that would be a separate issue. Temps are 28F today.
Core blockage or water pump seems to be most likely, but without a water pump, I would expect the temp to spike.
A flush has always worked on other vehicles to bring back some heat.
I have never had issues doing a core-only flush on other vehicles, but having a hard time seeing a good way to hook flush hoses up directly to the core inlet and outlet.
I read one post where they just cut into the hoses, then after flushing, they use a hose union and clamps to join the hoses back up.
Any more thoughts on why running without the Thermostate would be bad for 4-6 weeks as long as I give the truck enough time to warm up. I only ask as I was getting a little warm air when set up this way.
During warmup, Temp gauge always moves to the normal position. I did not see the new Thermosate opening today but that would be a separate issue. Temps are 28F today.
Core blockage or water pump seems to be most likely, but without a water pump, I would expect the temp to spike.
A flush has always worked on other vehicles to bring back some heat.
I have never had issues doing a core-only flush on other vehicles, but having a hard time seeing a good way to hook flush hoses up directly to the core inlet and outlet.
I read one post where they just cut into the hoses, then after flushing, they use a hose union and clamps to join the hoses back up.
Any more thoughts on why running without the Thermostate would be bad for 4-6 weeks as long as I give the truck enough time to warm up. I only ask as I was getting a little warm air when set up this way.
Last edited by mgolin; Jan 24, 2022 at 10:38 AM.
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
Any more thoughts on why running without the Thermostate would be bad for 4-6 weeks as long as I give the truck enough time to warm up.
I read one post where they just cut into the hoses, then after flushing, they use a hose union and clamps to join the hoses back up.
but without a water pump, I would expect the temp to spike.
Trending Topics
Thread Starter
|
8th Gear
Joined: Aug 2007
Posts: 8
Likes: 0
The flush kit is exactly what I have used many times. On the 250, I just do not see any easy access to the return line without cutting into them. For the line to the core, I can pull the hose at the water pump.
What would you recommend as the best way to check the water pump? Disconnect line to the overflow tank and look for steady flow?
Also, I do get more airflow with the temp dial on cold than I get with temp dial at hot. Maybe 80% flow. Should the airflow remain the same or is it possible the door is not opening all the way?
thank-you
What would you recommend as the best way to check the water pump? Disconnect line to the overflow tank and look for steady flow?
Also, I do get more airflow with the temp dial on cold than I get with temp dial at hot. Maybe 80% flow. Should the airflow remain the same or is it possible the door is not opening all the way?
thank-you
Last edited by mgolin; Jan 24, 2022 at 02:57 PM.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Fords to Drive Before You Die
Joe Kucinski
3 Best / Worst Features Of The 2025+ Ford Expedition
Brett Foote
10 Ways Ford is LOSING to the Competition
Joe Kucinski
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
Lead Driver
Joined: Mar 2006
Posts: 6,272
Likes: 438
From: IL
Did you burp your system?
Did you test the T-stat to make sure it's not sticking open?
How do the heater hoses feel?
The only way I know of to test to see if a water pump is working on newer vehicles is to remove one of the hoses and see if it's forced out. I saw a video a couple of years ago where a guy took an old upper radiator hose, cut it in half, inserted a clear tube, clamped it all back together so he could watch the flow...But you stated previously that you weren't over heating so more than likely it is not your water pump.
If it were me, I'd make sure you don't have air in the system. If you're confident that you do not, then I'd pull the T-Stat hang it in a pot of water and heat it up to see if the stat is opening if it does, pull it out and wait to see if it closes, or just go but a Ford T-stat and install it. The other guys all gave very good advice.
Did you test the T-stat to make sure it's not sticking open?
How do the heater hoses feel?
The only way I know of to test to see if a water pump is working on newer vehicles is to remove one of the hoses and see if it's forced out. I saw a video a couple of years ago where a guy took an old upper radiator hose, cut it in half, inserted a clear tube, clamped it all back together so he could watch the flow...But you stated previously that you weren't over heating so more than likely it is not your water pump.
If it were me, I'd make sure you don't have air in the system. If you're confident that you do not, then I'd pull the T-Stat hang it in a pot of water and heat it up to see if the stat is opening if it does, pull it out and wait to see if it closes, or just go but a Ford T-stat and install it. The other guys all gave very good advice.
Tuned
Joined: Nov 2017
Posts: 301
Likes: 144
Does it have a reservoir too? I had a newer work truck that would not get hot air either. The hoses were hot, the thermostat was working, etc.
What we found is the plastic reservoir had a pin hole leak that was so small you couldn't even see it. We noticed a spot of water from nowhere, traced it back.
It was strange, it would empty to a certain point, then only blow air.
If you looked at the reservoir, you would only think it needs topping off.
We changed it out with a new one, as it would not take a patch, problem solved.
What we found is the plastic reservoir had a pin hole leak that was so small you couldn't even see it. We noticed a spot of water from nowhere, traced it back.
It was strange, it would empty to a certain point, then only blow air.
If you looked at the reservoir, you would only think it needs topping off.
We changed it out with a new one, as it would not take a patch, problem solved.
Thread
Thread Starter
Forum
Replies
Last Post
38Chevy454
Modular V8 (4.6L, 5.4L)
8
Jan 18, 2011 11:08 AM