2.3L ('83-'97) 2.3 can't stay warm

[John501]

I know there are other threads on this but I have slightly circumstances. My little ranger's 2.3L can build/keep heat this winter. At first I though it was a stuck thermostat and bad sensor, so I replaced both, and I tested the thermostat before hand it came back good and opened at 192 degrees. The new sensor also works correctly since I tested the radiator with a thermal gun. The radiator at idle dropped the coolant over 45 degrees, I took the readings at the inlet and outlet hoses. So I covered half the radiator with cardboard, and it seemed to work great the gauge was almost at the half way point. But that was 50 degree weather, today got to the low 30s and I was driving home when I noticed the gauge barely holding on the the "N" in normal. I got home and check if my cardboard was still there and it is, even with half the cooling of the radiator covered I still can keep heat in the truck. I plan to cover 3/4 of it now and see what happens but I just want to know. Has anyone done something like this and still had the problem? Is there anything else I should do to the truck to help remedy this issue?

Thanks,
John

 

[19Walt93]

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.

 

[scotts90ranger]

Yeah, that, it's likely the heater core, my '90 has always had great heat but the gauge has always lived at the line just before the N in Normal, two different clusters, at least two different coolant temp senders... 3 different engines

Heater core is two hose clamps and 5 screws to change just an FYI, they're more expensive than they used to be like when I changed mine 15 years ago but I'd start with a flush, I need to do that on my '97 as it's acting similar to what you are talking about (and MUCH harder to change...), anything under 50F and I get very low heat output. On the '90 anything over 30F and I just leave it on floor defrost with the fan at the lowest setting and sometimes I'll have to drop it below full hot... always been t hat way turbo or not...

 

[Dirtman]

2.3's naturally run cold. They have a ton of iron and alot of cooling for such a small engine. I've known guys who have filled the blocks with concrete and ran them with no cooling system in demolition derbies. Obviously the car and engine was destined to be scrapped but they ran fine without cooling during the races.

But as said, your heater core would be the first thing to check. As well as the fan, if the clutch fan is stuck locked up it will also cause the engine to stay colder than it should. Also check that the thermostat is the right one, not only temp wise but size. I've seen them not seal properly in the housing and allow coolant to constantly flow around them.

 

[John501]

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.

Sorry guys this is on me, I forgot to add I put in a new heater core a month ago since the old one leaked coolant on my floor. I did go out and check the fan clutch, it didn't seem locked up or anything. Ive heard the heater core loop is always open is that true? As in it always has hot coolant going to it whether or not the heat is on. I do think that thermostat could have a leak around it, I double checked the size of the tstat which was right but the housing it goes into had tons of little rust crevasses for it to leak around so I might need a new one of those. I did find out my radiator is also leaking a little near the bottom close to the drain too. By the end of this the cooling system will be new.

 

[scotts90ranger]

So are you just having cold temp on the gauge or having low heat output? If the gauge is just low, forget about it... If no heater output then something must be going on.

Yes, there is no valve on the heater circuit, it's always circulating.

I put the old fan clutch on my '97 and covered 2/3 of the radiator with cardboard to try to get some heat output out of it but it didn't help. Turns out the computer sensor is seeing 180F but the gauge is low when it's colder out, I think the gauge sender is in the heater circuit...

 

[franklin2]

Sorry guys this is on me, I forgot to add I put in a new heater core a month ago since the old one leaked coolant on my floor. I did go out and check the fan clutch, it didn't seem locked up or anything. Ive heard the heater core loop is always open is that true? As in it always has hot coolant going to it whether or not the heat is on. I do think that thermostat could have a leak around it, I double checked the size of the tstat which was right but the housing it goes into had tons of little rust crevasses for it to leak around so I might need a new one of those. I did find out my radiator is also leaking a little near the bottom close to the drain too. By the end of this the cooling system will be new.

Even though it's new, flush it like the other guys suggested. If it works again for a week or two and then quits again, that is a sure sign you have a dirty cooling system with a bunch of debris laying in it somewhere.

 

[19Walt93]

Even though it's new, flush it like the other guys suggested. If it works again for a week or two and then quits again, that is a sure sign you have a dirty cooling system with a bunch of debris laying in it somewhere.

Bingo. New means new, new doesn't mean good. If there's rust in the system it'll plug a new one just as well.

 

[John501]

Even though it's new, flush it like the other guys suggested. If it works again for a week or two and then quits again, that is a sure sign you have a dirty cooling system with a bunch of debris laying in it somewhere.

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?

 

[John501]

So are you just having cold temp on the gauge or having low heat output? If the gauge is just low, forget about it... If no heater output then something must be going on.

Yes, there is no valve on the heater circuit, it's always circulating.

I put the old fan clutch on my '97 and covered 2/3 of the radiator with cardboard to try to get some heat output out of it but it didn't help. Turns out the computer sensor is seeing 180F but the gauge is low when it's colder out, I think the gauge sender is in the heater circuit...

Both cold on the guage and in the cab

 

[scotts90ranger]

That is strange... still have the tiny thin stock radiator (like 1/2" thick?), that's what my '90 came with before I converted to the V6 setup on it with the turbo and what my '97 has. The '90 has always had good heat, using more horsepower there's obviously more heat output now but even if I'm wheeling and sitting idle for half an hour it'll cook you out snow wheeling...

I'm gonna have to pull the engine in a few months to reseal but I can picture most of that system. I'm trying to remember the stock coolant flow path to the heater, I think thermostat housing to heater core then return to intake manifold? If so, intake manifold might be plugged up or something... definitely possible.

Computer coolant temp sensor is in the intake manifold where the coolant port on the intake manifold is and the gauge sender is on the back of the head behind the intake manifold. If the water pump was rusted away and not pumping you would think the coolant temp in the head would be high not low...

 

[John501]

That is strange... still have the tiny thin stock radiator (like 1/2" thick?), that's what my '90 came with before I converted to the V6 setup on it with the turbo and what my '97 has. The '90 has always had good heat, using more horsepower there's obviously more heat output now but even if I'm wheeling and sitting idle for half an hour it'll cook you out snow wheeling...

I'm gonna have to pull the engine in a few months to reseal but I can picture most of that system. I'm trying to remember the stock coolant flow path to the heater, I think thermostat housing to heater core then return to intake manifold? If so, intake manifold might be plugged up or something... definitely possible.

Computer coolant temp sensor is in the intake manifold where the coolant port on the intake manifold is and the gauge sender is on the back of the head behind the intake manifold. If the water pump was rusted away and not pumping you would think the coolant temp in the head would be high not low...

Yeah I believe it's all stock parts, except the replacement sensor, t stat and heater core. I think the water pump is fine, but I'm going to flush the system and see what happens.

 

[scotts90ranger]

Thinking back at it I think I missed a hose before, I think the return from the heater core is straight from the heater core but the supply to it is a combination of the small tube on the thermostat housing and the port from the intake manifold.

I'm still trying to wrap my mind around what's going on since it's similar to what my '97 is doing, on that thing the computer sensor is reaching 180F but the gauge is reading low sometimes, I think it has a flow valve in the circuit though and I might get to flushing the heater core out with CLR this weekend if I can...

 

[racsan]

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.

 

[RonD]

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