So I've got a 97 ranger 2.3/5spd w/ 120,000 miles and counting

early this winter I noticed the engine was having trouble warming. I though, no big deal, thermostat is sticking open.

The old one was a motorcraft, no clue if it was the original.

I replaced it with a cheapie from autozone. I noticed the spring on the new one seemed weaker than the old one. Overall it appeared to be inferior in design.

Anyways I threw it in, and the truck never warmed up then.

So I bought a motorcraft replacement.

Well, it warms up now, but it seems to be just as slow as with the original thermostat.

As winter got colder I had to resort to putting a mat in front of the radiator. Even then the engine is slow to warm up and when it does it seems the heater could be a lot warmer than it is.

I'm pretty sure it's not the heater core cause the engine itself takes forever to warm up.

The cooling system is not leaking on me, I've monitored the coolant level for a while and seen nothing disappearing.

I burped the air out very well I believe, parked on a hill and squeezed the hose while running and everything.

Back during the summer I made 2 5 hour trips back to back and shortly into it my engine light came on. Later on i had autozone pull codes and it was complaining about the camshaft position sensor. Occasionally the engine will have stumbleing spells, especially while cruising. I just chalked that up to the cps issue. I have yet to replace it.

So anyways, what do you reckon is causing my engine to not warm up well? I live in central indiana and recent temperatures range from 0-32 F

Any help would be appreciated.

 

i myself run a cover over the front grille during the winter (or below 50 degrees out) my truck warms up fine in the summer but, it does take longer when its bone-cold out. i had a 2.3 once and the only cooling system issue i had with it was a airlock that would cause it to overheat when you fully drained and refilled the cooling system. try finding a pyrometer (its a tool thats reads surface temps) see what your engine is really running at temp wise, you could check out temps at various locations and heater hoses. may or may not help, but thats where id go next.

 

You know you're pyrometer idea is not a bad idea!

I have a cheap one already.

So how do you like the "other" website so far?

 

nice '78. dad had a '77 F250 with the same motor & driveline. real snwplowing beast, just wouldnt want to feed it everyday, got 9 mpg. no matter what. you do have the thermostat in right? i recall something about my '88 2.3 having a small valve off to one side and it was supposed to go in a particular way. dont know if yours would be the same, just a passing thought.......good luck.

 

I couldn't see anything that would indicate that the thermostat needed to point in a certain direction.

I think what your thinking of is a air purge valve that helps burp the system.

 

When was the last time you had your cooling system flushed out? If there is a bunch of crud in the cooling system, the engine will warm up slowly. Perhaps a good back flush may solve your problem.

 

The thermostat should always be installed with the spring-side facing the engine.

Regarding particular installation on a 2.3L, my Ford Manual says this:

CAUTION: The thermostat seal (8590) must be positioned on the water outlet connection before the water thermostat is installed.

To prevent incorrect installation of the water thermostat, the water outlet connection casting contains a locking recess into which the water thermostat is turned and locked. Install the water thermostat with the bridge section in the outlet casting. Turn the water thermostat clockwise to lock it in position on the flats cast into the water outlet connection.

Clean the upper radiator hose connection, cylinder head and water outlet connection surfaces. Coat a new thermostat housing gasket with Perfect Seal Sealing Compound B5A-19554-A or equivalent meeting Ford specification ESE-M4G115-A. Position the thermostat housing gasket on the cylinder head opening.

It is critical that the correct water thermostat installation alignment be made to provide coolant flow to heater. Insert and rotate water thermostat to the left or right until it stops in the water outlet connection housing, then visually check for full width of heater outlet tube opening to be visible within the thermostat port in assembly.

This port alignment at assembly is required to provide maximum coolant flow to the heater.

 

Good idea to opt for the Motorcraft thermostat imo.

The thermostat DOES go in a certain way.

The "spring" goes in first/toward the engine & if it has the built in "air release valve", it should be in the up/12:00 oclock position, as this will aid in burping air from the cooling system upon refilling.

About the only way I can think of an engine over cooling is from a sticking open, or improperly installed thermostat, or the wrong temp range thermostat.

We should use the specified 195 deg thermotat, as thats the temp range the engine & oil were designed to operate with.

Another way to check the engines operating temperature would be with a scantool that'll monitor the computers engine temp sending units PID input to the computer.
This temp sending unit is seperate from the one that operates the temp gauge.

If you'll look in the "Tech Info" thread atop this forum, you'll find a link to the temp gauge sending units resistance profile, so with an ohmmeter you can see if it's output to the temp gauge is within spec, if you come to suspect it.

If the engine is warming properly, but the heaters output seems weak, try back flushing the heater core, as it may be sludged up, if the cooling system has been neglected.

If the heater core seems ok, look to the temp control, or blend door acting out.

You could also use a telescopic IR sensor to optically monitor engine block temp, without having to touch the engine. Many autoparts stores have them to loan for a refundable deposit, on their "loan-a-tool" program.

A bunch more thoughts for consideration, let us know what you find.

 

Ok well I used my infrared temperature sensor doodjamaflopper and I got 110-120 deg F at the top radiator hose going to the thermostat. I had just ran the truck for 15min or so, with the radiator rug still in place, and it was as warmed up as I could expect it to be.

The thermostat I put in, as well as the one I pulled out, was a 195 deg F version. So it's definitely running too cold.

At this point my heater is warm, but it can definitely be warmer. It would take a while to heat up the reg cab at this point. Heaters in other similar vehicles, after warmed up, would make my hand sweat, this one would simply make my cold fingers not hurt anymore.

I'm sure I didn't get the thermostat flipped around, otherwise my engine would be overheating!

As far as rotating it in the socket and the valve at 12oclock. I didn't see anything on the thermostat that looked like an air valve, it was uniform all 360 degrees.

I didn't see any tabs or grooves or anything else that would lock the thermostat in place, but I didn't turn it and it did catch and stop, and it held itself when I bolted the housing back on.

I believe the heater output was not blocked.

I didn't use a gasket, but I cleaned the surfaces and used some real tacky rtv stuff that's rated for coolant system use.

I suppose a piece of it could be lodged in the heater outlet, but the engine still runs cold so who knows.

I suppose a piece of it could be keeping the thermostat cracked open, but I would think the thermostat would be able to close on it anyway.

Now, something else that may be related, that I just thought of. The vent to the left of the steering wheel is never as warm as the main vents. It seems to put out much less air flow, and it is never nearly as warm as the main vents. I usually have it closed off for this reason. I figured it was a crack in the duct work or something, but you guys mentioned the blend door. Could this be related?

Now I'm not sure what the blend door does, does it blend hot & cold air to achieve your desired air temperature? Or does it move the air flow between the various vents?

My vent selector **** seems to work fine. I can tell it's vacuum controlled, but it quickly switches from windshield to floor to vents, to other combinations, etc. I do not notice any problems with it except that when I turn off the heater and shut down the engine, sometimes I hear the thing turn and it stutters and stops, like it's not totally smooth when it encounters less vacuum. I figure that's nothing.

And like I said, no coolant loss as far as I can tell. No smell, no grease spots, no level changes in the overflow tank. I don't bother opening the radiator cap because it lets air in according to the owner manual.

So based on all of that, what do you guys think?

 

And by the way, the truck runs fine other than the occasional stumble that's probably due to the bad camshaft position sensor that need replaced. That and it's got a slight exhaust leak I think at the donut gasket between the headers and the rest of the exhaust. I never smell exhaust or get a headache, but you can hear puft sound from it.

Seems like all stickshifts have that sound to their engines; coincidence? Maybe it happens easier because of the constant jerking from shifting? I don't know. But every stickshift vehicle I've seen, heard, seems to have a slight to severe exhaust leak.

Maybe it's cause people with tight budgets buy sticks, and they're less likely to fix a minor exhaust leak... Just a thought... It applies to me

I doubt this would effect my engines running temperature, but I have removed the air inlet muffler/baffle and replaced it with a slightly bigger piece of exhaust pipe. I also removed the rubber boot in front of the air filter that sits inside the fender. I read that this can help a little with performance, by opening up air flow.

 

Still sounds like a over cooling problem with those temperatures.

Just because the thermostat is new, doesn't automatically earn it a pass, as I've seen bad new parts right out of the box.
So you could pull the thermostat cold and see if it's stuck, or otherwise fouled open when cold.

How ever, you said you omitted using the specified thermostat gasket on thermostat installation & the thickness of the gasket may be needed to properly clamp & hold it into place when you install the upper radiator hose outlet connection, so it doesn't move & you get bypassing around the thermostat under pressure.

Could also be that some of the RTV has fouled the thermostat such that it can't close.

If the cooling system is dirty & hasn't been cleaned, why not consider back flushing it & add new coolant while it's opened up.

More thoughts for pondering.

 

I guess I'll have to flush it real good and maybe take a look at the thermostat again.

I was just hoping that there was something obvious I was missing that would explain everything. Guess I'm not that lucky

 

If you do the cooling system back flush yourself, remember our Rangers cooling system is designed for about 15 psi, so DON'T apply full home system water pressure, which is around 60-80 psi, when doing the flush & pop something.

You can get a "Prestone" flushing "T" kit to connect a garden hose to, at most WallyWorlds for less than $5 that works well.

I've used it with a section of scrap hose to fit it in when doing the flush, then removed it when finished, as I didn't want to leave the flushing "T" in place.

I also chose to back flush the heater core separately, so any crud collected there wasn't moved back into the engine block.

It also allowed me to monitor what was coming out of the heater core & when it ran clear.

Edit: The thermostat air bypass valve, if yours has one, is nothing more than a tiny stainless ball that seals a hole & is captured in a cage on the outer dia of the thermostat. So if yours has one, orient it up to the 12 o'clock position if possible as that could help get a better de-air burp.