Not enough heat
Thread Starter
|
New User
Joined: Jun 2004
Posts: 7
Likes: 0
Not enough heat
I have a 1994 Ford F150, 5.0 with A/C. A little while ago I noticed that I wasn't getting enough heat, I went and checked the coolant level and found it was ok. I checked the upper hose and it was warm and then checked the lower hose and it was cold. So I installed a new thermostat and CTS. Still I get the same problem. I rechecked the upper hose and it gets hotter. I had installed a new radatior last year.
I slid nearly off the upper hose to see it the thing was air bound and had no air come out(engine running) had some pressure, but was afraid to remove it off completly. I then pulled off the return heater hose and had flow come through. At this time I saw that the flow was very little. I checked the heater controls and found them to be working ok (flow door). I have no leaks or strange noises.
Questions
1. Could this be a problem with the water pump. Has anyone ever had a water pump go bad without leaking or making a lot of noise.
2. Could the heater core be plugged up (seems to me that there would be more pressure even if it were clogged up). Flow seems to be 1/5th it should be.
3. Would the bottom hose stay cold even after running the engine up to operating temperature.
Thank you in advance
Droff
I slid nearly off the upper hose to see it the thing was air bound and had no air come out(engine running) had some pressure, but was afraid to remove it off completly. I then pulled off the return heater hose and had flow come through. At this time I saw that the flow was very little. I checked the heater controls and found them to be working ok (flow door). I have no leaks or strange noises.
Questions
1. Could this be a problem with the water pump. Has anyone ever had a water pump go bad without leaking or making a lot of noise.
2. Could the heater core be plugged up (seems to me that there would be more pressure even if it were clogged up). Flow seems to be 1/5th it should be.
3. Would the bottom hose stay cold even after running the engine up to operating temperature.
Thank you in advance
Droff
Elder User
Joined: Jul 2004
Posts: 756
Likes: 1
If the engine doesn't run hot, the pump is probably ok.
I have had partially clogged cores before. I hooked a garden hose to them and blew them out in reverse flow with excellent results. Just beware if the core is weak, 40~80 psi of water pressure will blow a hole in it. When I did it I figured I was buying a new core anyways.
Another thing to look at is I have had foriegn objects get lodged in the air door and not allow them to close all the way. But with you having A/C, since your interior will be exterior when you get to the air door you may as well replace the core.
If it were me, I would attach a hose, and slowly open the faucet while watching flow, and watch all the gunk come out.
Good luck!
I have had partially clogged cores before. I hooked a garden hose to them and blew them out in reverse flow with excellent results. Just beware if the core is weak, 40~80 psi of water pressure will blow a hole in it. When I did it I figured I was buying a new core anyways.
Another thing to look at is I have had foriegn objects get lodged in the air door and not allow them to close all the way. But with you having A/C, since your interior will be exterior when you get to the air door you may as well replace the core.
If it were me, I would attach a hose, and slowly open the faucet while watching flow, and watch all the gunk come out.
Good luck!
Fleet Owner
Joined: Jan 2004
Posts: 26,007
Likes: 575
From: Brentwood,CA
there is a vacuum line coming of the valve on the heater core hoses take it and hook the line up to straight manifold vacuum if you then have heat it is the control board inside
Trending Topics
Elder User
Joined: Apr 2004
Posts: 544
Likes: 0
From: Ocala, Florida
I think you have a partially clogged heater core. I had that happen on a vehicle once. I had no heat in a blizzard. I fixed it the next day.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
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
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer