Engine overheats when Idling

[donalds]

Idle in park = 656
Neutral = 656
Drive or reverse = 624

 

[prince402]

For whatever it's worth, I had the same problem on my 94 Eddie Bauer with the 4.0 at about the same mileage. I installed a new radiator, new fan, new water pump and nothing helped. I just wanted to let you know that your problem is not unique. I never did find the cause.

 

[efBrianM]

Yesterday, I started the flush job, as recommended by some here. Went to O'Reilly's bought a quart of "radiator flush and degreaser" by Blue Devil.
Their directions are:
1. Drain the coolant out. 2. Refill with water and this 1 qt of flushing agent. 3. Run the engine for 20 minutes with the heater controls set to max.
For a deeper clean, drive it for 1 - 2 hours. I started it up and let it set and idle for 45 minutes - I was doing this in the evening, about 73 deg out, and the temp gauge stayed where it should be. I then I shut it off and let it set while I ate some supper. Went back out, and went for a 45 - 50 minute drive. Turned it off and let it set to cool off. Directions state that the flushing agent can stay in the engine for up to 4 hours. I figure it was in there for about 3 1/2 hours. I finished draining the stuff out at about midnight - way past this old man's bedtime.
Note that this is a 'gravity' drain! 4. Flush the system with water until all cleaner is removed. This is where I'm at today.

I want to do a back-flush with 'pressure' instead of just relying on the gravity drain, so I bought a Flush & Fill kit by Prestone that provides fittings so a garden hose can be hooked up.

Directions say to install the Flush TEE into the 'heater inlet' hose. Someone please tell me which heater hose is the heater inlet.

Brian

 

[Josh P]

If it was me, I'd buy a mechanical water temp gauge and connect it where the sending unit is for the dash gauge. That would determine how hot the coolant actually is. Use an IR thermometer to probe the upper and lower hoses. Does the 01 explorer have an instrument cluster voltage regulator? My 87 ranger would show running hotter than actual due to a bad instrument voltage regulator.

 

[efBrianM]

Ok, overdue for an update. I finished up the flushing job per my description above. Good news.
Test with the A/C "off":
With the vehicle parked, outside temp about 83-84 deg., started the engine and let it warm up,
and then let it continue to run for almost 1 hr - temp gauge stayed where it should of!! This is a pretty good improvement.

Test with the A/C "on":
Outside air temp about 85 deg., drove the vehicle at 20 mph with the A/C on for about 20 minutes
temp gauge stayed where it should of!! This also is a pretty good improvement.

Still doesn't like to idle with the A/C on, in park.

Not 100% fixed, but feel pretty good about the improvement.

I can see small black stuff floating in the coolant, so I'm going to flush it again.

 

[C420sailor]

Yeah...I mean, with the AC on you’ve got the condenser (in front of the rad) sending heated air into the radiator. So that decreases the radiator’s efficiency. Plus you have more load on the engine. Double whammy.

Still shouldn’t break a sweat in those temps, though. Do you have actual ECT numbers? Data always helps....

 

[fast_dave]

@efBrianM

Just sayin'

For a 1995, given that it's 26 years old (big emphasis on age hence the BOLD) and 188K, you're "in the zone" for head gasket replacement.

You wrote earlier that this overheating condition gradually started to show up the past couple of summers...

To me, this is the initial signature of a failing head gasket before actually blowing it out .

That small black stuff you're seeing in your coolant might be exhaust, oil, or head gasket particles, or a combination of all.

Long life coolants have made this condition not as frequently seen compared to when we were growing up with only choice being "green" coolant, BUT head gaskets haven't changed and they do have a service life.

Think about it, yours have had 26 years of daily heat cycles and they might be telling you something.

 

[Turdle]

For the idle speed issues, you may have a sticky IAC (Idle air control) valve. There is a thread with instruction for cleaning that.

 

[EB4X]

/\ True Dave...but I had my original H.G.'s on my '94 4.0 ohv when I sold her right around 247,000 .....no signs / symptoms of H.G. demise...ran flawlessly.

 

[donalds]

Lucky its a easy fix
Kinda cheap to

 

[C420sailor]

This is a SOHC though. Far, far less fun

 

[donalds]

This is a SOHC though. Far, far less fun

Well yea then that sucks

But a blown head gasket on a sohc is rare

 

[fast_dave]

@C420sailor - Sorry - I see my mistake - OP's signature is "1995 Explorer Expedition" so I assumed OHV

After seeing your comment, I went back and re-read the thread from Post #1 and the OP's talking about a 2001 w/ a SOHC.

@efBrianM - change your signature to what you're currently driving, LOL!

 

[MakinJeepsWeep!]

I tried to read everything but you have checked that you do not have a hose collapsing on you? I have a 96 with 275k some odd miles on it and i can sit dead still still over a hour ac full blast with 5.0 and the temp doesnt move, same in my 06 merc 4.0 with 210k some odd on it however i do stress to use a motor craft tstat the merc will even throw a check engine light if not a motorcraft tstat in it somthing about it opening at the wrong time. Sorry if i missed some post and this has already been covered.

 

[efBrianM]

Do you have actual ECT numbers? Data always helps....

Still have some of the abbreviations to learn, so what's ECT?

 

[efBrianM]

@efBrianM

Just sayin'

For a 1995, given that it's 26 years old (big emphasis on age hence the BOLD) and 188K, you're "in the zone" for head gasket replacement.

You wrote earlier that this overheating condition gradually started to show up the past couple of summers...

To me, this is the initial signature of a failing head gasket before actually blowing it out .

That small black stuff you're seeing in your coolant might be exhaust, oil, or head gasket particles, or a combination of all.

Long life coolants have made this condition not as frequently seen compared to when we were growing up with only choice being "green" coolant, BUT head gaskets haven't changed and they do have a service life.

Think about it, yours have had 26 years of daily heat cycles and they might be telling you something.

My bad on the profile. We have a 1995 OHV and a 2001 SOHC, so the information is still useful to me. The '95 has almost 216,000 on it.
Both engines have served us well, but their age is catching up to them.

 

[C420sailor]

Engine coolant temp. A code reader with live data can tell you exact coolant temp.

 

[efBrianM]

This morning I was sitting in the parking lot waiting on some results from a pharmacy. I let it idle and after awhile, the temp gage started going up. 78 deg's outside, no A/C!. Still think the flushing helped. Still planning on doing the flush again, changing the remaining 20 yr old hoses, and I'll go ahead put in another T-stat. It will be a couple of days, as I need the vehicle to make a couple of water hauling trips.
Side note: looks like I joined the 'rona club today. I may have to use the ship to home on the online purchases instead of running into town and picking them up in person. Feel ok though.

 

[efBrianM]

Engine coolant temp. A code reader with live data can tell you exact coolant temp.

Should have guessed that. Do the code readers that the parts stores use, have live data?

 

[donalds]

For the 2001
I'd go with a USB elm 327. OBD adapter
and free forscan App for pc

Under$20
EBay ... Amazon...
Best way to go IMO