Is it normal for my heater to warm and not hot? I've replaced my heater core, new t-stat, new radiator, new hoses. And it still just warm. What direction can I take on this? I can drive 20 miles and the heater is just warm. The temp gauge is half way. So that should be good enough to get hot heat?

 

Did you check the blend door in the heater box when you replaced the core? The hinges will break as they are just plastic, and pincles and other such things can fall down the defroster tubes and keep that blend door from working right. Just a place to start.

 

I didn't check it but i can hear the door opening and closing

 

how is your coolant mix?
feel the heater core hoses,do they feel hot?
do you have a real temp gauge? if so what is the actual coolant temp?
if your coolant temp isn't a good 190-200 you can block part of your radiator with some cardboard.
the coolant system in these trucks are massive,so they keep their cool towing in the summer heat.in fact i was able to run all summer without a working fan clutch,and not overheat (Maine doesn't get "terribly" hot.though we pushed 100* days with high humidity quite a few times this last summer.)
so it's to little surprise some may experience a lack of heat in the cab during very low temps.
did you use the proper Motorcraft E5TZ-8575-C Thermostat?

you may also want to inspect your temp switch in the dash,to make sure its actually turning up the heat the whole way.

in the older trucks,the seal around the blend door deteriorates.you may want to replace it.
some peoples are so bad,they installed a shut off valve in order for their a/c to properly work good in the summer.
of course,if you did this mod,you need to make sure the valve is open now,and it may be time to finally fix the blend door,so you can keep warm.

my truck heats me right right out of the cab even with windows down below freezing temps,and i need to turn the blower motor down,and eventually the heat as well,or i'll cook lol.

some members who do not tow heavy,etc remove the fan completely for better fuel economy and heat in the cab during the winter months.
a real temp gauge should be installed before attempting this.i would also be tempted to keep the fan and tools required to be able to put it back on roadside, should you need too.
or better yet,now would be a good time to experiment with electric fans,and see how things go.when the weather starts to warm back up in the spring,you could tell if the stock fan is better suited.

 

my coolant mix is more of 70/30 the reason i say this is because. I fill the truck with striaght water then i let it back out and refill my radiator with striaght antifreeze no 50/50. so my block had water in it already. So i'm not sure if this a 50/50 mix or not.
My heater hoses are HOT!!! I'm going to check my door this evening when i get off work.

 

well the first thing to start with is of course would be to test and correct the mixture for your location.

Coolant Mix and Overheating

http://www.magers.org/handy/antifreeze.html


once that is corrected,you may find the heater core is air trapped.
this doesn't normally happen after a core change,but it can.

 

but i did notice the first day i changed my heater core, it was really HOT and the temp hand went over a lil. But this morning it did heat up nearly the same. Now the day i changed it wasnt that cold outside either not sure if this has anything to do with it. But today it was like 20 degrees outside and it didnt get hot just luke warm.

 

This!

My truck was luke warm, I replaced the heater core and now it is a furnace, even last week when it was 17 degrees...

 

you might need to block the radiator in the winter time keep in mind these are diesel engines with massive cooling systems not a lil gas burner lol. my truck runs about 195-200 degrees in the summer and its been about 0-6 degrees this weekend and now it runs 175-180 and the heat sucks so im gonna be blockin off part of my radiator to get the engine temp up. it runs much better at the 195-200 range

 

What do you normally use to block it off?

 

haha cardboard is an option there are attachments for the front end just have to google it

 

just a peice of cardboard, tie it up to the core support

 

What happens when the cardboard gets wet and turns to mush? or do you cover it with something first? I'm thinking I might want to try this, its 3/4 of the way to work before I start getting heat.

 

take the fan off the truck you will have better heat and mpg

 

yea but its way easier to zip tie the cardboard than it is to go get a fan clutch tool and jack with that and chance it slipping off and putting a fist into the radiator