New Guy with a question!

[Adams95]

Hey everyone I've been a longtime lurker here, but I finally have my own explorer and now my own question. Here's just a little bit of info about my '95 explorer sport 4.0 ohv:

My buddy owned it since before i met him 3 years ago (he bought it at 65,000 miles), over the past year he's brought the explorer over to my house a few times to do some much needed repair of worn parts. After working on this truck and finding out how easy it is to work on, I started to really warm up to the idea of owning an explorer and started looking around for a good deal.

Fast forward to a couple days ago...His family is moving and he didn't think the explorer could make the cross country trip. I ask him about the explorer and he's nice enough to give me the truck! (I'll post pics tomorrow for everyone)

Now it has a few issues that I'm working out, keep in mind the truck is at 215,000 miles or so. Here's the issue I'm currently working on:
Horrible gas mileage and loss of mid range power...about 8-10mpg.

First thing I notice is the engine never gets to temperature. I helped him replace the thermostat 2 months ago and that helped bring up the temperature a good amount but it only goes up a 1/4 of the gauge, not halfway. Keep in mind its getting around 100 deg here in vegas and with the A/C running full blast the gauge doesn't even move above that.

The cooling fan spins all the time, even on completely cold startups. I've checked the fan clutch and when the engine is cold it has a fair amount of resistance, I'm able to spin the fan about 1/4 of a turn with my hand.

Only thing left to check is the ECT right? Tomorrow I'm going to pull it out and test the ohms, but is there anything else this can be?

Any kind of input is welcome and thanks for reading through my long post

 

[svt4cam]

Greetings and welcome to the board. Cooling fan should always spin it's on a viscous clutch which cuts down it's RPMs @ higher engine speeds. My guess would be you have a bum thermostat. I've had this problem several times over the years with replacement Tstats. Buy a new one and toss it in a pan of boiling water to make sure it functions normally before installing. If the engine never gets up to normal temp that could account for some or all of the crappy mileage.

 

[yavapaires]

I agree with the above post. However, there are a couple things I would add. 1) you can't trust the factory gauge to be accurate. On my 96 the gauge only shows about 1/3 of the way under normal conditions. Watch the gauge from when you start up to when the engins is warmed up. Mine will go up to about 1/2 or maybe a little more, then when the thermostat opens, it will drop to about 1/3 and stay there. I might see some deviation at times. 2) I would get a thermometer and manually check for proper operating temp. Infrared would be best. You can check Harbor Freight, or some other online outlet. They are usually quite pricey from the local parts house.

 

[yavapaires]

Another thought, Check for a bad O2 sensor

 

[Joe Dirt]

...and since it's a '95, check the codes, live and stored- easy with a paperclip.

 

[Adams95]

Hey everyone, thanks for the suggestions. I kinda screwed up checkin the codes this afternoon...I got the key on, engine off codes: 335 and 336. However after I got the codes for the key on, engine on test I reset the computer. Come to find out the codes I got were for missing the Goose and not cycling the O/D button...lol

However, today I cleaned the MAF and the Air Charge Sensor. After doing so I started up the truck and what a difference! Before the idle was hunting and even in park if you punched it real quick you could hear the motor kinda fighting itself through the initial rpms. Now the idle is perfectly stable at 900rpm and sounds healthy when you give the throttle a nice blip. It does drive a bit better, but still is missing a lot of power.

I also pulled the headlights now and am cleaning them as we speak. I plan on changing the thermostat tomorrow and flushing the radiator. Do you think with the KOEO codes I can determine anything? Also another important note is that the CEL never comes on when driving around, no matter how long.

Here a couple pics I took today, you can see how bad the headlamps look too

Also here's a pic today when i was out driving around, this was in 105 degree weather and the A/C blasting. I think you just might be right svt on the thermostat, when I picked up the new one today I made sure it was 198 degree.

 

[bobflood]

If that pic of your temp guage is what you normally see, I would not worry. My '97 5.0L has run that temp for years, regardless of outside temp, load, speed, etc - I consider it "normal"

 

[Joe Dirt]

Agreed...

Nice Ex! Very clean!

 

[Adams95]

Thanks Joe! I love this truck and have just been going through givin it the TLC it's been needing. Last night I used Meguair's Plastix to get the terrible oxidization off my headlights. I learned some important lessons, that some of you might already know...

1. Don't bother trying to clean the inside of a headlamp
2. Using Formula 420 to clean your headlight like a water pipe = fail

I think the headlights are a pretty nice improvement and will definitely do the trick until i get projectors. As you'll see in the picture, the driver side headlamp was the one I tried to clean the inside of.

My project for tonight is to do the radiator flush, I know for a fact my buddy never "burped" the coolant system, so there is definitely air bubbles in the coolant. Not to mention I opened the radiator cap to see the coolant looks exactly like Chocolate Milk...So I'm sure my little explorer will be feeling like a champ after this.

Also I did a fair amount of driving today and after cleaning those sensors the truck drives much better and has a little bit better throttle response. I think the big difference is going to be when I swap out the 2 oxygen sensors in the exhaust. I found out from my friend that even though the truck is at 200k+ miles, he's never changed the O2 sensors...

 

[shadowless127]

My temp gauge is also a little screwy, but my trusty OBD-II Scanner tells me temps, so I'm not terribly worried.

Coolant flush is also on my list... mine looks like it's never been flushed.

 

[RomeovilleIL]

Adam, that temp location looks normal on the guage so dont be concerned if you replace parts and end up with the same guage reading.

I see the brake lamp is lit. Is it on all the time? Normally that indicates the brake fluid level is low or the parking brake is applied. The poor milage could be dragging brakes!

 

[Adams95]

I did the flush last night and I'm sure my little truck appreciated it. The coolant was a clay like color but no chunks were in it. I drove the truck to work this morning, which is about a 20 min stop and go drive. It never got up to the temp in the pic above and gauge kept going from almost warm to cool, depending if I was stopped or driving.
Should I be concerned? I'm thinking I should test thhe ect. What do you guys think?

 

[bobflood]

I did the flush last night and I'm sure my little truck appreciated it. The coolant was a clay like color but no chunks were in it. I drove the truck to work this morning, which is about a 20 min stop and go drive. It never got up to the temp in the pic above and gauge kept going from almost warm to cool, depending if I was stopped or driving.
Should I be concerned? I'm thinking I should test thhe ect. What do you guys think?

Assume that the guage goes down when you are moving and up when stopped - right? I would look at fan clutch and/or thermostat first, then the sending unit for the temp guage.

 

[Adams95]

Assume that the guage goes down when you are moving and up when stopped - right? I would look at fan clutch and/or thermostat first, then the sending unit for the temp guage.

Bob you are correct, I just replaced the t-stat with the flush and the fan clutch appears to be in working condition...I spun the fan by hand when the engine was cold and it can only spin about a 1/4 turn no matter how hard i spin it.
Is there another way I can test it?

 

[bobflood]

Bob you are correct, I just replaced the t-stat with the flush and the fan clutch appears to be in working condition...I spun the fan by hand when the engine was cold and it can only spin about a 1/4 turn no matter how hard i spin it.
Is there another way I can test it?

Assume that your fan is driven off the engine directly thru a viscous coupling? I believe the fan concept is that as temp goes up, coupling stiffens up and fan spins closer to engine speed and thus pulls in more air across radiator. If yours is stiff when cold, it may indicate that it pulls too much air and thus cools too much when engine temp is still low.

 

[Adams95]

See from what I've read on the forums here, is that the fan clutch slows the fan RPMs down when the engine is cold, but lets the fan spin freely at normal operating temperature.
If this is the case the fan clutch appears to be working, when I get home after work I'll pop the hood and spin the fan and see if the resistance is no longer there.

 

[bobflood]

See from what I've read on the forums here, is that the fan clutch slows the fan RPMs down when the engine is cold, but lets the fan spin freely at normal operating temperature.
If this is the case the fan clutch appears to be working, when I get home after work I'll pop the hood and spin the fan and see if the resistance is no longer there.

I think that is backwards. If the fan viscousity is stiff, it will turn at the same speed as the engine - ie, it's "max" speed. As it warms up, the viscousity drops so it "slips" more and the fan blade will spin slower than the engine.

 

[Adams95]

So after testing the fan clutch with the engine warm, it is very stiff. Which from what I read on here is the appropriate result. But other than that, I started thinking about replacing the O2 sensors, they have 200,000 + miles on them. However when I run the KOEO/KOER both tests come back as '111' all systems normal.
Do you think its worth replacing the O2 sensors even though the truck isn't throwing any codes? Also with a '95 4.0 OHV shouldn't there be only 2 upstream O2 sensors and thats it?

 

[bobflood]

So after testing the fan clutch with the engine warm, it is very stiff. Which from what I read on here is the appropriate result. But other than that, I started thinking about replacing the O2 sensors, they have 200,000 + miles on them. However when I run the KOEO/KOER both tests come back as '111' all systems normal.
Do you think its worth replacing the O2 sensors even though the truck isn't throwing any codes? Also with a '95 4.0 OHV shouldn't there be only 2 upstream O2 sensors and thats it?

Ok - let me try this again, cause I partially screwed it up last time. The whole concept behind the viscous coupling is to allow the fan to turn SLOWER than engine speed, thus pulling less air thru the radiator, at lower temps. With the engine OFF and the engine COLD, the fan should spin more "freely" because the viscousity should be lower. Thus it will run slower than the engine speed and pull less cooling air thru the radiator. As the vehicle heats up, you want to pull more air thru the radiator, so thus the viscousity should get stiffer, allow less slippage, and the fan therefore should turn faster. You said earlier that you only can spin the fan about 1/4 of a turn when the engine is cold - that seems like too little, thus indicating that the viscousity is too high and the fan will pull more air than you want when the engine is cold. This could retard it from stabilizing at operating temp.

Why would you want to replace O2 sensors without an indicator from the computer that they were bad?

 

[Adams95]

Ahh thank you bob, that makes much more sense, it's also the best explanation i've read of what the fan clutch does exactly. What kind of resistance should I expect when spinning the fan while cold? 1 full rotation or so?

I replaced the IAC last night, I had tried cleaning the old IAC however it only helped the idle a little bit. The previous IAC was constantly howling, and the idle would sometimes hunt between 900-1200rpms back and forth. After replacing it the truck drives much smoother and the idle is rock solid.

Also the reason I was thinking about replacing the O2s was just because they are the stock sensors and have 215,000 miles on them. What do you think bob? Thanks for all your help throughout this thread as well