Help! Engine running HOT, heater blowing COLD

Joined
Mar 2, 2007
Messages
4
I have a 1987 PU 4x4 reg cab. The temp gage shows HOT, almost overheating, but the heater is blowing ice cold air. I installed a new water pump, new thermostat, I checked the heater valves and they're all opening and closing properly. I've also noticed a slight smell of anitfreeze outside the car but never see drips or leaks. Any ideas???
Thanks, G
 
Joined
Jul 4, 2006
Messages
208
i agree with tntoyota.lift the front of the truck with a jack until radiator cap is a at least a little more than waist high.open the heater valve(turn temp to warm).add antifreeze.let it run with the cap off until the thermostat cycles(you will see the coolant flowing in the radiator).top off radiator.fill reservoir just over proper level.if it has air in that should take care of it
 
Joined
Feb 27, 2002
Messages
2,891
Probably a heater core. Welcome to 8 hours of bad back. Check your lines where they go into the dash, are both hot? Check the heater valve to be sure it's moving through the entire travel range when the cable to hot is pushed.
 
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Jul 10, 2006
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North Pole, AK
Hate to say, but it very well could be a bad HG. MIne had the exact same symptoms, and I found a bad Hg to be the culprit. In case it's not, pull the termostat and see if the truck colls down. If it does you have a bad/ reversed thermostat.

TK
 
Joined
Mar 2, 2007
Messages
4
I have a funny feeling its the heag gasket too. There are no leaks but i keep very slowly loosing water and I can smell a slight sent of anti-freeze... I'll try to prime the system (as discribed above) and check again for leaks. Then, I guess its time for a new HG and while I'm at it, I might as well replace the head (timing chain was done by the PO). Thanks again guys!
 
Joined
Feb 25, 2007
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Nampa Id
what color is your antifreez. my coolant (green)turned a dull grayish green color in only a month when my gasket started leaking
 
Joined
Apr 1, 2007
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Northern Arizona
Your heater blowing cold, could be a clogged core. My `85 4Runner was blowing cold. I flushed it out, at the lines going into the firewall, several times. It would work a while and then blow cold again. I finally had a radiator shop do a power flush to the heater core. Not all shops can do this, so check around first. They told me that it was a 50/50 shot at clearing the heater core and the worst that could happen is that the core would start leaking. That was 7 years ago and it has worked fine since the flush. What cause my to be plugged was most likely someone had put Stop-Leak in the radiator and it plugged the heater core too.

Kevin
 

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