Heat problems
Thread Starter
Junior Member
Joined: Oct 2010
Posts: 12
Likes: 0
Heat problems
Hey have a 89 f150, When I got it the coolant system was gunked up with rust bad, and the heater did not work.
I flushed the system using a coolant flush additive, No luck still no heat,
I flushed the system indivisiualy, radiator, heater core and block. No heat still.
Ok well I changed the heater core and flushed the system again with a water hose at full pressure busting all my hoses lol... yeh replaced them all and still every time I flush it pure rust comes out. SOME heat now... but not enough to keep me too warm on the 20 degree mornings.
replaced the water pump aswell for good measures and glad I did because I never seen so much built up gunk behind it...
The heat gauge I put in seems to be working, I can say the only thing I havnt replaced is the Thermostat (because I forgot to put it on while I had everything off lol).. but its getting up to 195 degrees and stays there, I should have great heat at that temp.
What can I do about all this rust? I heard CLR but I also hear it doesn't work well with aluminum, The over the counter Radiator flush didn't impress me much.
I need some heat aswell!!! any opinions?
I flushed the system using a coolant flush additive, No luck still no heat,
I flushed the system indivisiualy, radiator, heater core and block. No heat still.
Ok well I changed the heater core and flushed the system again with a water hose at full pressure busting all my hoses lol... yeh replaced them all and still every time I flush it pure rust comes out. SOME heat now... but not enough to keep me too warm on the 20 degree mornings.
replaced the water pump aswell for good measures and glad I did because I never seen so much built up gunk behind it...
The heat gauge I put in seems to be working, I can say the only thing I havnt replaced is the Thermostat (because I forgot to put it on while I had everything off lol).. but its getting up to 195 degrees and stays there, I should have great heat at that temp.
What can I do about all this rust? I heard CLR but I also hear it doesn't work well with aluminum, The over the counter Radiator flush didn't impress me much.
I need some heat aswell!!! any opinions?
Senior Member
Joined: Jul 2007
Posts: 3,805
Likes: 480
From: Cape Girardeau MO
A belated Welcome to the Site!
If you can push water through the heater core, rust or not, you should be getting some heat. I would recommend pushing water through until no rust, but understanding your efforts, we'll move on.
Are you sure the heater damper is working? On our model year, it's controlled by cable - make sure the damper swings fully closed on the full right slide of the temp control lever. There is a clip on the cable that can be adjusted. If nothing else, make sure the damper is towards full heat and clamp it in place - worry about the rest when the weather moderates. This can be accessed through the glove compartment access panel - about 8 screws, and voila - full access to the core and the damper.
If your core has been replaced in the past with a 'cheapie' core - eh, well my experience is that this style core does not deliver full capacity due to some blinding in efforts to cut costs. Doesn't only affect heat, but defrosting abilities.
Make sure your system is full - leave the radiator cap off and let the thermostat do its job, and fill appropriately until full. A low level will affect the heater - usually will be good at higher RPM, not so good at lower RPMs.
A properly functioning OEM-spec core should be able to run you out of the cab, regardless of outside temps, IMO.
Good luck, and keep us posted.
IMO, you have found one of the best sites for members willing to step up and help, versus yield a bunch of cheap shots on one's abilities. The more you can tell us, the better the help - remembering the challenge to troubleshoot without actually being there. :-)
If you can push water through the heater core, rust or not, you should be getting some heat. I would recommend pushing water through until no rust, but understanding your efforts, we'll move on.
Are you sure the heater damper is working? On our model year, it's controlled by cable - make sure the damper swings fully closed on the full right slide of the temp control lever. There is a clip on the cable that can be adjusted. If nothing else, make sure the damper is towards full heat and clamp it in place - worry about the rest when the weather moderates. This can be accessed through the glove compartment access panel - about 8 screws, and voila - full access to the core and the damper.
If your core has been replaced in the past with a 'cheapie' core - eh, well my experience is that this style core does not deliver full capacity due to some blinding in efforts to cut costs. Doesn't only affect heat, but defrosting abilities.
Make sure your system is full - leave the radiator cap off and let the thermostat do its job, and fill appropriately until full. A low level will affect the heater - usually will be good at higher RPM, not so good at lower RPMs.
A properly functioning OEM-spec core should be able to run you out of the cab, regardless of outside temps, IMO.
Good luck, and keep us posted.
IMO, you have found one of the best sites for members willing to step up and help, versus yield a bunch of cheap shots on one's abilities. The more you can tell us, the better the help - remembering the challenge to troubleshoot without actually being there. :-)
Springer Spaniels Rule
Joined: Jun 2009
Posts: 3,445
Likes: 17
From: Milltown, NJ
It might be a little messy, but use a shop vac to suck the crap out of he engine, leave the water in it the water will help draw out the crap, disconnect the heater core hose and vacuum out through the hose.