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2.3L ('83-'97) 2.3 can't stay warm


John501

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Well lets think about this for a minute......................

The thermostat is 190deg(approx.) which means it shouldn't be open at all unless coolant at the thermostat is 190deg
So there would be no, or very little, coolant flowing to radiator until t-stat opens a bit

So the covering of the radiator with card board is not done for the radiator, its done to prevent cold air from coming into engine bay while driving
Radiator should stay cold in winter months, its not a required part of the engine's coolant circulating system, its only used to bleed off EXTRA HEAT generated by the engine, thats the point of the t-stat, it only includes the radiator IF engine coolant gets above 190degF

If temp is still low that means the engine itself can not generate enough heat with fan circulating the cooler air in the engine bay
You could remove the fan but thats a pain, an electric fan conversion is a possibility but costs money

Check your fan clutch, it may be broken and stuck in "locked" mode
After engine sits over night or at least 6 hours, open the hood and try to spin fan, it should be hard to spin
Start cold engine, let it run for 20-30seconds, shut it off
Try to spin fan again, should be EASY to spin, unlocked mode, if not then fan clutch is bad, which causes too much air circulation in cold weather

You could insulate the heater hoses, doesn't cost much for those "pool noddle" type foam insulation tubes
Heater hoses do bleed alot of heat, even a bit of insulation on the longer sections can help

Feel free to cover the whole radiator to stop the air flow into engine bay
You see that done on many semi trucks in winter, they use zippered or snap on grill covers to stop air flow into engine bay to keep engine temps up
Thanks, ill try this out tomorrow I never really knew exactly how to test the fan clutch my friends just said if you cant spin it its bad. so ill try this better test in the morning after its sat for awhile.
 


Rock Auto 5% Discount Code: 7FA902352B4C01: April 5th, 2021

John501

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Ive had 3 trucks with the 2.3 lima, all 3 had low heater output, below 50 I have 1/2 the radiator covered with cardboard. The current truck has all new parts ( radiator, water pump, thermostat, heater core ) Ive thought about tossing the mechanical fan for a electric one, just have a manual toggle switch for it. I always keep heat control on floor/defrost. it will keep the window clear but even though its a regular cab ive never been too warm in the winter, my ‘93 supercab 4.0 though would heat up nicely.
A mechanic friend recommended just removing the fan completely during winter since the truck doesn't need it so I might go that way. Yeah I got an explorer with the 4.0 it never fails to super heat the cabin.
 

franklin2

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Alright when I throw a new radiator at, I will also flush it out, and probably put on some hoses too. How should I go about flushing it, I have used a watering hose before and just blasted it through each part of the system. Any tips on it?
Take the heater hoses off the engine, and the spray the water hose in one, and then the other flushing the water both ways through the heater core till you get good flow out of the other hose. Try to avoid taking the hoses off the heater core at the firewall, its very easy to crack the header in the heater core when trying to the get the stuck hoses off.

You can also do a quick diagnoses when the engine is fully warmed up, and you should be getting heat but you are not. Sitting there in the driveway idling fully warmed up, you should not be able to hold your hand on the upper radiator hose. That will tell you if the coolant is fully warmed at or above 190F. If that checks out, then feel the heater core hoses. They too should be hot. You may be able to grab them for a second but you will quickly let go, they are pretty hot also. If they are not and you can hold onto them, or you can hold on to one but not the other, then there is not enough flow through the heater core.

Also make sure your heat door is closing properly. It mixes outside air with the air going through the heater core to control the temperature. If it's not closing all the way when the control is moved all the way to hot, it will let cold air into the system all the time.
 

John501

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Take the heater hoses off the engine, and the spray the water hose in one, and then the other flushing the water both ways through the heater core till you get good flow out of the other hose. Try to avoid taking the hoses off the heater core at the firewall, its very easy to crack the header in the heater core when trying to the get the stuck hoses off.

You can also do a quick diagnoses when the engine is fully warmed up, and you should be getting heat but you are not. Sitting there in the driveway idling fully warmed up, you should not be able to hold your hand on the upper radiator hose. That will tell you if the coolant is fully warmed at or above 190F. If that checks out, then feel the heater core hoses. They too should be hot. You may be able to grab them for a second but you will quickly let go, they are pretty hot also. If they are not and you can hold onto them, or you can hold on to one but not the other, then there is not enough flow through the heater core.

Also make sure your heat door is closing properly. It mixes outside air with the air going through the heater core to control the temperature. If it's not closing all the way when the control is moved all the way to hot, it will let cold air into the system all the time.
Man, thanks for the write up, I appreciate it. I'll update the thread with the results.
 

John501

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Alright an update on my ranger, I had my mechanic flush out the system. After this I got it warmed up to half way, I then opened the hot and check the heater core hoses, both are hot without the blower-motor running, although one was slightly less hot than the other one. I then turned on the blower, and one cooled down noticeably but was still hot. The upper rad hose was also hot, so the t stat works. I believe the blend door is switching to heat all the way, since I tested it manually with its cable. Today I was driving in very light snow, and noticed even with the truck fully warmed up, and the heater full blast just on defrost my windshield started to ice over. So I'm starting to think I should replace the heater core again, thinking it still might be slight clogged.
 

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Possible, if heater core is only partially passing hot coolant
Core can have good flow just thru the top area, so both hoses are hot but 1/2 the core, lower 1/2, is blocked so never gets hot and so heat in cab never gets as hot as it could

190degF is HOT, lol

The heater cores are not expensive and easy to change, pre-1995, so maybe worth it to do it
You can tell if old core was blocked by its weight after its out
The new core will weigh almost nothing
After dumping out the coolant from old core it should also weight the same, if its heavier then it was/is clogged

After new core is in hook up either heater hose at firewall and leave the other off
Add coolant to radiator until it starts to come out the open port of heater core, it's full, put other hose on
This is how you should always refill cooling system after coolant change or repair, 1 heater hose off at firewall, this allows air out of the engine side of thermostat.
 
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Yes, believe it or not if the heater core is partially obstructed the engine temp will go down. Unhook the hoses and flush it in both directions, if it doesn't help it certainly won't hurt and you can do it for free.
Can you explain this a little further? I'm not seeing how it could make the engine run cooler if the heater core is blocked.
 

19Walt93

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Can you explain this a little further? I'm not seeing how it could make the engine run cooler if the heater core is blocked.
It doesn't make sense and I'm not sure why it happens but I've seen it several times.
 

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FWIW, both heater core hoses should be so hot you cannot keep touching them with the engine warmed up. If you can keep contact with either, it is not flowing coolant through the core as much as it should, likely due to blockage in the core, OR an air bubble in the core. If you had air in the core, only a section of the tubes/fins would have hot coolant, so they would have their heat extracted, moreso than if all the fins/tubes were in contact with hot coolant. IOW, with less coolant in the core, more heat will be extracted from what is there, making it cool more.
tom
 

John501

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FWIW, both heater core hoses should be so hot you cannot keep touching them with the engine warmed up. If you can keep contact with either, it is not flowing coolant through the core as much as it should, likely due to blockage in the core, OR an air bubble in the core. If you had air in the core, only a section of the tubes/fins would have hot coolant, so they would have their heat extracted, moreso than if all the fins/tubes were in contact with hot coolant. IOW, with less coolant in the core, more heat will be extracted from what is there, making it cool more.
tom
Alright so my core definitely has a clog in it, or an air bubble, since I could keep my hand on one of the hoses. But I'm going to say it's clogged a bit since I tried to make sure no air got in it.
 

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If you run it with the cap off till the upper radiator hose is hot (that means the thermostat is open) any air in the system will be pushed out. Then make sure the overflow bottle is half full and the hose to the neck is in good shape, and put the cap on and turn the engine off and let it cool. It will then suck any coolant it needs from the bottle into the radiator as it cools, avoiding any air coming in.
 

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Just take one heater hose off at the firewall and fill system via rad cap opening until coolant comes out the core and the hose thats off
DO NOT start the engine, when you see coolant coming out then the air is GONE, for sure, the little bit that is left will come out on its own after a few heat up and cool downs, thats what the Over flow tank is there for
 

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Agree with Ron, that's what I did when I flushed mine, worked great ;)
 

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I would be almost tempted to just change the heater core on a pre '95 Ranger if it is plugged than screw around trying to unplug it... being 5 screws and two hose clamps... or at least take it out to do the unplugging since the hoses are going to be off anyway. I just was curious enough to feel the heater hoses on the '97 the other day and one is cold, here's where I'm envious of the second gen dash I almost convinced myself to look for for a daily driver...
 

John501

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Just an update for everyone, I put in a new radiator, and took out the t stat housing to clean it up. I was able to use a dremel to smooth out any pitting where the t stat gasket sits. That has help Abit it seems to have stopped coolant from leaking past the t stat. I'm going to try and do the heater core next week, I'll update the tread once that's done.
 


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