Need more heat

I have an 87 B2000 that runs fine but I'm not getting enough heat... I get some but it does not seem consistent and I'm going to need way more once winter hits and the temp drops to -35 Celsius and sometimes -50 Celsius (for you guys in the US, that's really, really cold ) once you factor in the chilling effect of the wind.

What steps should I take to diagnose my heat problem?

Someone told me to empty the rad, hook up a water hose to the "out" and flush it out, then put in fresh antifreeze. Is this advisable?

I'm looking forward to your suggestions.

Cheers !!

P.S. I just checked a Celsius/Farenheit conversion chart and the temps are pretty similar in the minuses, ie -35C is -31F and -50C is -58F.

maybe a hott thermostat.. make sure your heatcontrol valve works and all the heater switches work on the consol

your heater core itself may be corroded and partially plugged. if you replaced it - better flow = more heat

My heat did not work that great ether and when it did it was very weak. before you do anything under the hood get down on your knee and look up beside the gas pedel under the dash. when you are looking turn the hot cold switch (or get someone to trun it for you). if you dont see anything moving down by the gas pedel (it will be right above the tranny hump) then your hot/cold switch is busted. That is not uncommen on these truck out of the 2 I had bouth were busted. If you wont I can take a pic when it gets light out and post it up of were im talking about.

also if that isn't it before ppl go drastic sayin the heater core is bad - there are ways to see if it is .


is your floor boards wet? - bad heater core
is there a smoke coming from your vents ? heater core

but like you said - drain out your radiator and take the thermostat out - check it if its busted thats your reason why no heat as well - get a new thermostat and gasket (8$ for both give or take ) and clean your thermostat housing really good then put it back together then leave the drain plug out of your radiator and put your hose on in the top - have someone start the truck let it run while you flush the system . flush it til its all clear water .shut the truck off then put the plug in again and refill with a 50/50 mix of anti-freeze and water (or use straight antifreeze) .. Then start the truck let it get warm again and put the heat on full blast see what it does .. you should be toast in mins.



If its still cold and does not fix the issue then your heater core is clogged- before disassmebly order your self a new heater core and when it comes in then disassemble .


to change your heater core you have to unhook the hoses that go thru your fire wall in the middle of the wall be prepared for water/antifreeze there . And move them away . Now go in side - ready? ok- you're gona need 10 mm sockets to get the bolts out of the dash . thats right you have to remove the dash to get the heater core out of the truck no ifs ands or buts . I've taken 2 dashes out its not that hard to do -


brake down :

***1 bolt on each end of dash (hidden by covers ) take them out -
on the top of the dash theres 3-4 bolts- you'll need to get a wobble extention as this is a difficult place to get with a regular socket-

***on each end of the dash theres 1 bolt on that stays in the dash you are removing the nut off it as this bolt slips into a bracket on the cab walls.

***Take gauage cluster out i believe if i remember right theres 1 bolt in there
under the dash again the lower vent that is screwed in - remove that theres a mounting plate for the colum - 2 bolts 14mm-15mm remove them that will let the colum lay down out the way .

*** open glove box remove insert theres 1-2 bolts in there -

*** remove heat /ac benzel and unbolt the controls for your vent and settings (simple little nuts one them ) you'll have to unscrew the heater control from the dash as you will have to push that thru inorder to get the dash away enough to gain access .



I'm sure i'm forgeting something but for warned if you do this your self its easy - and saves you money - sending the truck to a mechanic to do will cost you 300-400 simply cause of labor involved with takin your dash in and out . hehe . if i'd known how to take the dash apart 4-5 years ago i would have kept the mazda i had back then it had a bad heater core too- had wet floor - shop said 300-400 to do it -

the part it self will probably run you about 50$


DAMN I JUST wrote a techy . lol .

And I thank you for it... especially the part about removing the dash. I'm probably going to do that anyway since I have a broken passenger vent grill that I want to replace. If by doing what you propose (new thermostat and antifreeze) I get my heat back then cool. However, once I remove the dash to change the grill I will also plan to change the heater core, for good mesure.

wet floor board is a clear sign of bad heater core-
and a aweful smell in grey smoke coming out the vents would be heater core as well . as a word of avise. .


If i had a mazda here i'd do a bunch of pics for dash removal - did you know you can remove the broken vent after you take the dash out?? It should pop out form the back . i still have my old dash but its at storage - i'd love to do a tech on the dash removal but i don't have a mazda here any more to show /point where you take bolts out -


Go here to look for a new heater core : they are superb in service and quick with shipment. i've bought parts from them a couple times .

AS For the thermostat housing - its 2 10mm bolts - also when you put the new thermostat in make sure the thermostat is pointed (theres an arrow on the thermostat) towards your radiator - This is also a good time to inspect your radaitor for damage leaks and corsion . (SP?)

Thermo should also have a small air bleed hole in it.Put the hole at 12 oclock when u install it. BJ

Should my fan be running all the time or should it just kick in when needed?

It seems to me my fan is running all the time...

Could be the source of my problem with the low heat ???

Yep.Fan should engage when u first start truck up.U hear a loud roaring noise.Fan clutch has a bimetal spring in it.As engine warms up,spring expands and causes clutch to slip less and therefor fan runs more to cool truck.In cold weather spring contracts,clutch slips more and fan turns less.Good way to test is spin the fan before u start truck on cold day.Fan should spin freely.Check again when truck is hot.Fan should be hard to spin.If ur clutch is bad I have a good one out of my 2200 I will be glad to sell reasonably.BJ