No Heat!

[knightrider31782]

Hi everyone, i just purchased a 2000 Toyota Tacoma, 2.4L, automatic,
2wd, about a month ago. It was a fleet vehicle for a company that my uncle worked for so i got it for dirt cheap, but is in very good condition but it has 360,000 miles on it, anyway the problem i'm having with it is that the heat does not work, it just blows cold air, so far i have replaced the thermostat and the fan clutch, but it didn't help at all, the truck also overheats sometimes, but not always and the outside temp doesn't seem to play a roll in wether it wants to overheat or not, and it only does it if it has been driven for a while, and only at idle in park or at a stop light for at least 5-10 minutes, so i beleive these 2 things are related although i could be wrong. The engine does not loose any coolant
and the cooling system seems to be operating normally, the next thing i was planning to do was replace the water pump, but i don't want to waste the money\time if that is not the problem, the pump does not make any noises and doesn't leak, so i was wondering if anyone else out there has had a similar problem? or has any ideas on how to diagnose these 2 problems? or how else i could tell if the water pump is operating normally?

[knightrider31782]

OK guys heres what i found so far when messing around under the dash, i found that the switch that controls hot, cold and in between clicks when u turn it from one end to the other, so the cable some how controls some push rods of such under the center of the dash which tell the blower to blow cold or hot air and the switch was only moving it a little bit from one end to the other making it pretty much lean to the cold air side, so i manually moved the rod all the way to hot, and sure enough it went to freezing in my cab to toasty warm so i'm not real sure what needs to be replaced though but for the rest of winter i'm going to just leave it on hot and in the summer i will move it back over to cold for my A\C, and when i have more time (and when it gets warmer out) i will take apart the dash more and see exactly whats causing the cable to hangup when turning the nob, and as for the over heating i haven't done anything yet until i see if its gone, but am still open for suggestions with that problem, and maybe to as why that cable is clicking and hanging up like it is. Ok well i will check back in a few days to keep u posted on the situations and see if anyone has any ideas yet.

[Flash75]

I don't think the heater problem is related to the engine overheating problem. You said the cooling system is working ok but obviously it isn't because it sometimes overheats. I doubt if replacing the water pump will help. It's a good idea to verify that your heat gauge is working correctly, use a kitchen thermometer to check the coolant temperature. It's good idea to get the cooling system and radiator cap pressure tested. Most good garages and radiator shops can do the pressure test. Try flushing and cleaning the cooling system with a heavy duty cleaner suitable for aluminum. If that doesn't work remove the radiator and have it checked for flow capacity, it may be clogged.

Clifton

[knightrider31782]

Originally Posted by Flash75

I don't think the heater problem is related to the engine overheating problem. You said the cooling system is working ok but obviously it isn't because it sometimes overheats. I doubt if replacing the water pump will help. It's a good idea to verify that your heat gauge is working correctly, use a kitchen thermometer to check the coolant temperature. It's good idea to get the cooling system and radiator cap pressure tested. Most good garages and radiator shops can do the pressure test. Try flushing and cleaning the cooling system with a heavy duty cleaner suitable for aluminum. If that doesn't work remove the radiator and have it checked for flow capacity, it may be clogged.

Clifton

I haven't done anything with the over heating problem yet, (because its snowing outside right now) but i just wanted to add to your reply that the radiator was replaced about a year ago when it was owned by the fleet company, for what reason i have no clue, but i would think that could narrow the problem down a little more, and the coolant was also flushed out a year ago, and has been done about every year before that, since it was new, i would also like to add that it uses long life coolant, i'm sur that doesn't make a difference either way but just wanted to have the facts clear. ok i will check back this weekend and hopefully have an update. oh yeah i forgot someone also told me that i could have air or an air bubble in the cooling system, causing it to over heat, and i was also told that there should be a bleeder screw on the thermastat housing but i cannot find one. If anyone knows where it is on this perticular truck please drop me a line, and on how to bleed the system of any air bubbles. ok thanks again i will pressure test the system and cap as soon as i get a chance, but like i said before it isn't loosing any coolant, and the oil stays very clean between changes, but i'm not sure if the cap is holding enough pressure, so i will check it out anyways. Thanks.

[Flash75]

The shop manual does say to bleed the system after changing coolant. I have a 2.4 engine and cannot locate a bleeder screw and the manual doesn't say how to bleed the system. Try loosening the top hose at the radiator for bleeding. I have also loosened a heater hose on other vehicles for bleeding. It may help if you can jack up the front of the truck when filling the system.

Clifton