Flareside98

Hi there,

Im new to the forums as a member (always have lurked due to the amount of helpful things) but now Im in urgent need of help. I apologies if this is posted in the wrong board as this is my first post.

I have a 1998 4.6L V8 and the heater has decided to stop working. Im in northern British Columbia where it's normal for the temperature to drop to -20 to -40 degrees Celsius (-4 to -40 Fahrenheit for the friends from the south). Earlier in the fall the heater would work as normal and no issues but one morning it just stopped as I was running around downtown. If I have defrost on full blast it will blow cold air for about 20-30 minutes, then if I switch to panel heat the air is a bit warmer but will not get any warmer than that.

The first thing I did was check my coolant levels which were full. I had an oil change done just for good measure (I was a bit over) and that didnt resolve the problem either. My father thinks its my thermometer but I am doubting that because my engine temperature acts normal and the gauge reads as it should (correct me if this could be the case, Ive read that it could be the thermometer if the engine temp is very low or very high and the heater reacts to this measurement, but mine has been acting normally).

I had an older code pulled that I knew about before for running lean, but when I first found it a few months ago, the heater was working normal.

Im looking for some troubleshooting other than that, as a student running to the mechanic isnt very cost efficient and I would say im fairly handy at problem solving so Im not afraid get my hands dirty (all my maintenance and repairs have been done by myself)

Thanks for any advice.


Update: Went for a drive so engine warmed up, both heaterhoses going into the firewall were warm.

BrittonN

I feel ya! I'm from Northern BC too, -18 here right now. I had a problem like you're having with an older vehicle of mine that I sold. The Aerostar vans engine would be warmed up but the cab heater would only blow cold air. My uncle who is an hvac mechanic recommended a heater core flush, which I never did. Once I sold the van the lady I sold it to had the heater core flushed and that seemed to fix the problem.

Im not sure if you can flush the heater core yourself, but that may be something to look into.

jstockert

I would check the blend door actuator. Maybe broke and not opening the blend door. Thus no heat.

Flareside98

Still no warm progress :/

I turn the key to get all the gauges working and can hear the blend door motor turning when I adjust the **** so Im thinking of ruling that out. It has a consistent sound every turn and no clicking or snapping noises to indicate its broken.

Ive changed out the thermostat and has made no noticeable difference, it still heats up normal and shows a normal temperature as I had before. I didn't change the coolant or flush the system with water but my next step will be taking it to a shop to flush the whole system or the heater core and clean it out.

Any other takers?

c9night

Try installing new thermostat it is pretty easy. It is about $15 easy fix. If it is heater core you are looking at 1,000 or better. It takes about 13 hours to pull that out and the it is behind the dash. Be careful of flushing it out. If you do it could break things and cause leaks.

Flareside98

I did the thermostat this afternoon, was much easier than I expected but still having problems. If I do a flush (which seems like the only option I have left) i'll bring it to a mechanic to do it.

Is there any fused related to the heater? Wondering if it could be as simple as that.

TheUnforgiven71

My opinion is the blend door your hoses are warm and providing heat to the heater and you state that you have no issues with temp or fluid level issues so it has to do with the flow of the heat which is the blend door the motor doesn't have to be bad in order for the blend door to be bad the connector of the blend door is cheap plastic that gives out after so long which won't open the door even though the motor works fine, just to let you know it's not an easy job, I have the same truck and getting to the heater n blend door requires pulling out the dash board n tight spaces to work in. I wish you Good luck with it though.

bobkyle2

The blend doors on these trucks are total crap. You might hear the blend door actuator turning, but i bet the door is broke.

Check out the heater treater f150 on youtube, They tell you how to remove the blend door without taking the whole dash out. Its a mess either way you change it.

Manuellabour247

A flush on your heater core isn't as bad as they say......in summer months. Easiest way is to get a hose with an adjustable nozzle, then disconnect your hoses at the firewall if possible. All you do after that is lightly open the nozzle to put flow one direction through the core system. Let it run for a bit, then do the same for the other side. I have done this for years on all brands of cars and trucks. Seems to work perfectly......but again it was during the summer or fall. With your cold temperatures, I'm not sure a hose would work unless you have a heated garage to do it in. Then all you would need is a pan big enough to catch the fluid.

EDIT**Also, Ford has a problem with the blend doors going out. Just one of the small parts that will eventually bite you in the rear. There are tricks to help get it out....but I hope you aren't a weight lifter with meat hands or you're going to have problems getting to it. Lol

gustrider4

They make a flush kit that you can by at NAPA. thats were i got mine. in my bros 1999 expedition, we rulled out that it wasnt the thermostat, wosent the blendor, so we went ahead to flush it. and now its heats. Not to 100% like my f150, but it does get the truck warm enough to make it comfortiable.