heat problem

86 Toyota. Truck gets warm up, turn the heat on, 2 minutes later, its cold air. Anyone know?
Reply to
J K
Loading thread data ...

Do you have a temp. guage? If so, does the coolant temp change? Do you hear any gurling sounds from the dash with the heater valve open and reving the engine? If so, may be air trapped in the system (heater core is highest point in the system) or you may have a head gasket leak (blowing exhaust into the cooling system - do you have any coolant loss?). Also, check the cable that operates the heater valve on the firewall. It slips off real easy.

You might have a look at this:

formatting link

Reply to
Roger Brown

hear any gurling sounds from the dash with the heater valve open and reving the engine? If so, may be air trapped in the system (heater core is highest point in the system) or you

you have any coolant loss?). Also, check the cable that operates the heater valve on the firewall. It slips off real easy.

Reply to
Jim

The heater core is simply a heat exchanger. Obviously, not enough of the heat transfer fluid (your coolant) is passing through the tubes. Not too many things that could cause this. Either it's stopped up or the valve is not allowing enough fluid to enter the tube side of the exchanger. I haven't heard of it happening in Toyota's but my '96 Impala SS has a real problem with the heater core gooping up on the tube side (it's a comon thing with these cars and has something to do with that orange coolant the system uses).

Also, scale doesn't conduct heat worth a damn. As scale builds up inside the tubes of the heater core, your heat transfer coefficient will get drastically lower. This combined with the lower fluid flow (scale makes the tube ID smaller) can seriously impact the amount of heat that the heater core can deliver, eventually making it useless.

I don't buy the 'trapped air' thing. It's a forced convection system. I don't care how high the heater core is, unless the fluid flowrate is pathetically low (ie, a trickle), the air will be pushed out. And, in that case, the low fluid flowrate is the problem and not the supposedly 'trapped air.'

If this is something that happened all of a sudden, I would guess that your valve is not opening. If, on the other hand, you don't regularly flush your system and the heater has been gradually loosing its punch over the years, I would guess that the thing finally clogged to the point that it just can't do the job anymore.

Luther

Reply to
Luther

In the old days, if you were traveling across the desert and your car was overheating, one trick was to turn the heater on high and turn on the fan. Sometimes that little bit of added radiator area would keep your car from boiling. Another trick was to put a 2X4 or something similar between the hood and front bulkhead, then close the hood so it only caught on the safety latch. The opening allowed more air to flow into the engine compartment helping, a little, to keep the engine heat down.

Memories are fading... :>))

Tom - Vista, CA

Reply to
TOM

It usually bleeds off itself, you can drill a small (1/16") hole in the thermostat flange to help it escape, or run the engine up to temp with the radiator cap off/heater valve open to allow excess air out of the system. Can also help to park facing up a steep hill to get the heater core lower than the rest of the system. I've never had this problem myself (w/ trapped air) but have heard the above suggestions on how to eliminate it.

Reply to
Roger Brown

Try removing the free bumper I gave you. You never did pay for the $52.00 shippijng charge. I should have just laid the thing on the street and gave it to the first person who stole it. I would have had the same satisfaction and not all the hassles of shipping a bumper half way across the country.

Reply to
Brad Taylor

satisfaction

Brad, For what little it's worth to you, this proves the "what goes out comes around" doesn't it? He cheated you and now he's got a broken vehicle. Sometimes we get to see it come around and it makes it a little sweeter. I know I'm not supposed to be that way but I can't help myself. :-) davidj92

Reply to
davidj92

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.