Solved Coolant temperature and possible AC issue?

[GreaseMonkey1709]

Howdy all! Did some major work on wife's 1998 Explorer 4.0SOHC, and am stumped...
Couple months back, I did the dreaded timing chain repairs after the guides shattered, and now the car runs amazing! However, I attempted to reuse the apparently garbage plastic thermostat housing, which proved to be a mistake... After 2 gallons of readded coolant later, I ordered a fancy aftermarket aluminum thermostat housing, which has been amazing so far, no overheating at all, and no leaks.

Now here's the weird part... After installing this new aluminum thermostat housing (which came with new sensors, and new thermostat), I noticed the temperature gauge rise VERY quickly to operating temp, within about 30-40 seconds of a dead cold start... It does this consistently, with no change. The upper rad hose doesn't even feel remotely warm yet, once it does this, so I assume the thermostat isn't even remotely close to the claimed temperature yet... A day later, when getting on the freeway on ramp, I got P0117 check engine code, obviously in relation to the temperature sensor(s).

While all this happens, the AC will only blow scorching hot air while sitting still idling, but switches to icy cold when I start moving...

I thought maybe I switched the 2 sensors on the housing by accident when I plugged them in, but came to discover that the harness is actually slightly different between the two, making that impossible (presumably?)

Any ideas?? This car is killing me

 

[Lee's Automotive]

Howdy all! Did some major work on wife's 1998 Explorer 4.0SOHC, and am stumped...
Couple months back, I did the dreaded timing chain repairs after the guides shattered, and now the car runs amazing! However, I attempted to reuse the apparently garbage plastic thermostat housing, which proved to be a mistake... After 2 gallons of readded coolant later, I ordered a fancy aftermarket aluminum thermostat housing, which has been amazing so far, no overheating at all, and no leaks.

Now here's the weird part... After installing this new aluminum thermostat housing (which came with new sensors, and new thermostat), I noticed the temperature gauge rise VERY quickly to operating temp, within about 30-40 seconds of a dead cold start... It does this consistently, with no change. The upper rad hose doesn't even feel remotely warm yet, once it does this, so I assume the thermostat isn't even remotely close to the claimed temperature yet... A day later, when getting on the freeway on ramp, I got P0117 check engine code, obviously in relation to the temperature sensor(s).

While all this happens, the AC will only blow scorching hot air while sitting still idling, but switches to icy cold when I start moving...

I thought maybe I switched the 2 sensors on the housing by accident when I plugged them in, but came to discover that the harness is actually slightly different between the two, making that impossible (presumably?)

Any ideas?? This car is killing me

Could be a lower temp tstat that opens too quick or a faulty temp sensor

 

[Turdle]

Both sensors can't bad. You have an air bubble in cooling system.

Raise the front high, get radiator cap higher than the heater hoses on firewall, run heater, hot temp, floor vent. Let cool, check coolant level in radiator. Fill reservoir only after burping.

If this fails, you could have a bad thermostat. Is it possible it was installed backwards?

 

[Lee's Automotive]

Both sensors can't bad. You have an air bubble in cooling system.

Raise the front high, get radiator cap higher than the heater hoses on firewall, run heater, hot temp, floor vent. Let cool, check coolant level in radiator. Fill reservoir only after burping.

If this fails, you could have a bad thermostat. Is it possible it was installed backwards?

My bad I had a similar issue when my ect sensor went bad it would climb within 20-30 seconds of a cold start

 

[GreaseMonkey1709]

Both sensors can't bad. You have an air bubble in cooling system.

Raise the front high, get radiator cap higher than the heater hoses on firewall, run heater, hot temp, floor vent. Let cool, check coolant level in radiator. Fill reservoir only after burping.

If this fails, you could have a bad thermostat. Is it possible it was installed backwards?

Hm... I'll try that after work tomorrow, but I did the exact same procedure I used when I reinstalled the engine, when I added coolant and burped it... Although the leaking thermostat housing probably allowed the air bubble to escape

And no, it's impossible to install the thermostat upside down, due to the design of the upper thermostat housing.

 

[GreaseMonkey1709]

My bad I had a similar issue when my ect sensor went bad it would climb within 20-30 seconds of a cold start

Not sure what brand the sensors and thermostat are, which makes me suspicious of both when I installed the aftermarket housing... I just hate throwing parts at things.

 

[Lee's Automotive]

Not sure what brand the sensors and thermostat are, which makes me suspicious of both when I installed the aftermarket housing... I just hate throwing parts at things.

Yeah same when i first got my X i replaced the housing with a cheap plastic one on ebay and actually had a bad sensor right out of the box i just ordered the aluminum housing for the 02 4.0 X that has the clip in style sensors and i ordered a factory thermostat from the dealer i only ordered them because the plastic housing is leaking and i have no heat which could be a possible issue with a clog or could be a fault tstat too so i decided to order everything and get it fixed before it gets cold

 

[donalds]

Here is how I get the air out of my cooling system

Coolant Bleeder valve

I have been putting off changing my wife's coolant The thousands of threads on burping the system THERE HAS TO BE A BETTER WAY This is what I came up with Hope this helps someone some day This mod cost me $5.39 and about a hour I put a flat spot on the coolant pipe with a hammer Just feed...

www.explorerforum.com

 

[Lee's Automotive]

Here is how I get the air out of my cooling system

Coolant Bleeder valve

I have been putting off changing my wife's coolant The thousands of threads on burping the system THERE HAS TO BE A BETTER WAY This is what I came up with Hope this helps someone some day This mod cost me $5.39 and about a hour I put a flat spot on the coolant pipe with a hammer Just feed...

www.explorerforum.com

Now that's convenient except I ordered the one-piece hose so I can delete the metal pipe since its rusty

 

[donalds]

Now that's convenient except I ordered the one-piece hose so I can delete the metal pipe since its rusty

Rust can be removed and parts can be painted

 

[Lee's Automotive]

Rust can be removed and parts can be painted

Yeah true but i'm lazy lol im actually following this thread and using the hose for the 01 explorer 4.0 Upper Radiator Hose - confused - 1998 4.0 liter SOHC

 

[Pete Deering]

Howdy all! Did some major work on wife's 1998 Explorer 4.0SOHC, and am stumped...
Couple months back, I did the dreaded timing chain repairs after the guides shattered, and now the car runs amazing! However, I attempted to reuse the apparently garbage plastic thermostat housing, which proved to be a mistake... After 2 gallons of readded coolant later, I ordered a fancy aftermarket aluminum thermostat housing, which has been amazing so far, no overheating at all, and no leaks.

Now here's the weird part... After installing this new aluminum thermostat housing (which came with new sensors, and new thermostat), I noticed the temperature gauge rise VERY quickly to operating temp, within about 30-40 seconds of a dead cold start... It does this consistently, with no change. The upper rad hose doesn't even feel remotely warm yet, once it does this, so I assume the thermostat isn't even remotely close to the claimed temperature yet... A day later, when getting on the freeway on ramp, I got P0117 check engine code, obviously in relation to the temperature sensor(s).

While all this happens, the AC will only blow scorching hot air while sitting still idling, but switches to icy cold when I start moving...

I thought maybe I switched the 2 sensors on the housing by accident when I plugged them in, but came to discover that the harness is actually slightly different between the two, making that impossible (presumably?)

Any ideas?? This car is killing me

While all this happens, the AC will only blow scorching hot air while sitting still idling, but switches to icy cold when I start moving...
1. That cause by the coolant fan. Fan clutch is not working. Air is not being drawn in. Thus it cool when moving. Very Common problem with a electric fan cars.

noticed the temperature gauge rise VERY quickly to operating temp, within about 30-40 seconds
2. That is because of the fan clutch not working

 

[GreaseMonkey1709]

While all this happens, the AC will only blow scorching hot air while sitting still idling, but switches to icy cold when I start moving...
1. That cause by the coolant fan. Fan clutch is not working. Air is not being drawn in. Thus it cool when moving. Very Common problem with a electric fan cars.

noticed the temperature gauge rise VERY quickly to operating temp, within about 30-40 seconds
2. That is because of the fan clutch not working

The fan clutch is functioning, that's one of the first things I checked. It's also not electric, don't think 2nd gens ever got electric fans from the factory...

 

[Turdle]

Now that's convenient except I ordered the one-piece hose so I can delete the metal pipe since its rusty

Send it to me, I'll make it purty

 

[Lee's Automotive]

Send it to me, I'll make it purty

Lol I already have the one-piece hose but thanks for the offer, bro

 

[Pete Deering]

The fan clutch is functioning, that's one of the first things I checked. It's also not electric, don't think 2nd gens ever got electric fans from the factory...

I was just pointing out a common problem with electric fans car. In short you have a air flow problem.

Did you remove the blade assembly from the clutch? If so its reversed

 

[Taxhero]

With the a/c issue, that can be very common if there’s no airflow through the condenser, such as if you’re having issues with the fan clutch. Once you are moving you’re getting the air going through regardless of the fan.

If you removed the radiator, be sure it isn’t blocking part of the condenser, or that you didn’t damage the cooling fins.

The best way to test the ac while a vehicle is parked is by having a squirrel cage fan blowing air through the front, simulating the car moving. This is important especially when it’s hot out and humid. Also have your high and low pressures checked. Too high pressure is going to cause it to be hotter, and the heat from the condenser will also affect coolant temperature with the hot air blowing through the radiator

 

[GreaseMonkey1709]

After alot of parts shotgunning, I discovered it was a faulty temp sensor (ECM). switched back to the factory one, everything functions correctly now.

only took me over a year

 

[C420sailor]

Interesting.

I wonder if there is system logic to cut the AC compressor off if the ECM detects the engine overheating…

 

[GreaseMonkey1709]

Interesting.

I wonder if there is system logic to cut the AC compressor off if the ECM detects the engine overheating…

That's exactly what I thought, but I was constantly getting check engine codes that I finally caught with my scanner after several months, and it was the ECM complaining that the engine wasn't reaching op temp fast enough

That being said, I can only assume that it was going into limp mode, and that doesn't allow the AC compressor to cycle?