2.3L ('83-'97) Help with air in system/ no heat at idle 1996

[Kailash]

So basically i changed some sensors a couple weeks ago and drained the system. When I went to fill it up I could only get about half of the fluid in.

I really don’t want to have an overheating issue so I replaced thermostat, water pump, radiator. (Timing belt while I was there)

so I tried it again. I got a more fluid in this time but still not full capacity. I started it up and ran the heat but only got heat when I reved the engine. Heat stopped at idle. The engine didn’t suck more coolant as it warmed up.

I am getting a new radiator cap tomorrow but if that doesn’t do it I’d like some ideas.

I doubt it’s a heater core issue cause heat was fine before I drained it to begin with

my temp gauge is inoperative so no use for diagnostic

 

[scotts90ranger]

It's cold enough here your temp gauge probably isn't going to move (below 50 without my radiator restricted it won't move on my '97), especially just sitting parked at idle... my '97 takes like 5 miles for the gauge to move to/from work, I blocked off half the radiator just to get any heat output out of the heater which got the temp gauge up some and the fuel mileage to go back up when it's cold out... I have one of those cheap OBD II blue things with the Torque app and it still doesn't go over 180F when it's under 50 out...

When I had my radiator out after I got in the accident it only took about a gallon and a half to fill it up with the bigger automatic transmission radiator that's all you can get now...

 

[Kailash]

The gauge is bellow the c and doesn’t move. Fuel gauge is also inoperative so I think it might just be that part of the cluster

 

[scotts90ranger]

If the upper radiator hose or the heater hose that comes from the thermostat housing are getting warm then the coolant is flowing, the heater hose will warm up sooner since it is bypassing the thermostat. The system will not use any coolant out of the radiator until it warms up to increase pressure in the system then creates a vacuum as it cools, if it's pressurized there's no way to suck out of the overflow bottle. If that helps anything.

It does sound like there might be a wiring issue to your gauge, possibly a missing ground

 

[RonD]

To test Temp Sender and dash Temp gauge you just need to Ground the red/white wire on the Sender

In 1996 2.3 I show the Temp Sender as a 1 wire sender, grounded by its Threads when screwed into the engine
Its at the drivers side rear near the Oil Pressure Sender(also 1 wire)

2.3l locations seen here: https://cimg4.ibsrv.net/gimg/www.ranger-forums.com-vbulletin/500x441/0996b43f8021b7e1_d3c13ce3af4920cf917bb86d6913e996a27c731c.gif

Cold engine, unplug this sender's red/white wire, ground it to Battery negative or any convenient ground
Turn on the key
Temp gauge should go to HOT, all the way up
If so wire and gauge are OK
If not then there is a problem with wire or gauge

Never use tape on Sender threads, oil or temp, they need a good ground to engine


To make sure you get most of the air out when refilling coolant remove 1 heater hose at the firewall
Fill the system, air will come out of the engine side of thermostat via the heater hose and heater core port
When coolant starts to come out of both, put hose back on, and remaining air will be purged on first warm up

On startup feel BOTH heater hoses, both are cold, of course
Fan/blower off/low
Let engine idle for 3 to 4 min, feel the hoses at the firewall, again
Both should be heating up, heater core is clear, maybe
If one hose is much warmer than the other then heater core is clogged
Reverse heater hoses at the firewall, should do this every 2 years in any case, helps keep core cleaner
See if you get better flow back
Once both hose are warmer, turn fan/blower to HIGH
Feel the hoses again
One should be "a bit" cooler, if its alot cooler then heater core is clogged


1996 uses an electric Blend Door, common issue if Temp Knob doesn't seem to change temp
If you can change Temp, i.e. turn knob to COLD once you have heat, and it gets cold, then that's working


2.3l Lima engine is a large block of metal, so hard to get warm and stay warm with just 4 cylinders heating it
Common complaint is limited heat in cold weather, radiator is often not even used with temps below 32degF
People in northern areas often put cardboard in front of radiator in winter to keep engine temp higher, reduces cold air flow into engine bay when driving
Also pipe insulation on Heater Hoses
Coolant Temp gauge should run above 1/3 after 5-8min of driving on the 2.3ls, 3.0l/4.0l will run just below 1/2
The reason 2.3l runs lower is because Temp Sender is at the rear of engine, not the top front where coolant will be hottest, but it should still be 185-195degF at upper rad hose/thermostat

You can get 205degF thermostats for the 2.3l instead of the 190-195degF

 

[scotts90ranger]

I wasn't watching Torque app this morning but it took 10 miles to get to the C on the gauge this morning at 45-50mph on the highway (line of like 20 cars, it was cold but not slippery even though the front guy thought it was apparently...) so probably 120F and that's with the radiator half blocked off...

 

[Kailash]

Well I lost my log in but I think I got it all fixed a week or two ago.

I still have a slight gurgle when switching heat from on to off but I think that's due to a heater hose that is ziptied

 

[Kailash]

Thank you both immensely

 

[Kailash]

I'll share a few interesting points.

This all started because I had a bad temp sensor that I wanted to replace

So I Replaced it but the Guage was still reading below the C. Turns out Scott was right and it just takes forever to warm up/ always reads low. I was just too scared of the air in my system to run it long enough to find out

I tried Ron's venting method and was able to get more coolant in than before but still not full capacity until I also lifted the front of the truck up while filling

Yesterday I Replaced the idle control valve which improved the low idle I was having which I believe contributed to my low heat at idle

 

[scotts90ranger]

If you want a really neat way to fill a cooling system that gets rid of almost all air pockets in the system get a vacuum fill kit, I bought the Harbor Freight version for around $60 last year and it isn't too bad, we use the Snap On version at work since GM REQUIRES it to be used on their new direct injection V6 and V8 engines since the coolant passages apparently do dumb things, the LS engines are bad enough but the DI engines are worse... Anywho, it's simple and quick, you run compressed air through a venturi with some attachments creating a vacuum at the radiator cap, then shut off the air then open another valve to suck coolant from a bucket or jug while watching the pressure of the system. This way finds any hose leaks you might have testing the system for pressure backward and fills the system pretty good.

Last radiator I changed I was at my brothers and not by an air compressor so didn't use it, but it's kinda nice as it gets things full without doing dumb heat cycles...

When I fill a 2.3L I push and squeeze on the upper radiator hose to help get coolant to the top of the thermostat which helps a lot, if I think about it before I get too far I sometimes even go as crazy as taking the radiator end of that hose off and pouring coolant down the upper hose... but I'm usually lazy and squeeze the hose until I'm sure it's full then put a bunch in the overflow bottle and let it warm up then fully cool down...

BTW, glad you got things sorted out! I know I didn't have much heat last week when it was cold as heck...