Explorer fan question

[toddz69]

A lot of us have the Explorer fan/clutch setup on our trucks now.

Has anyone ever actually heard the fan "come on", i.e. sound like a jet taking off for awhile. And if so, how much did the engine cool down before it stopped and what brand clutch do you have on it?

My truck is open and fairly noisy with engine and wind noise and I don't think I've ever heard the fan spool up. I read conflicting information on what temp it's supposed to kick on too.

TIA,
Todd Z.

 

[DirtDonk]

Haven't noticed a distinct change on mine even at higher temps Todd. But I do think it runs at least partially all the time. Never really disconnecting fully.
I didn't think much about that though, as most fan clutches I've ever had had quite a big of drag to them even when cold.

Now, my brother's '66 Corvette fan acted like a secondary jet engine linked directly to the temperature gauge. Dead silent one minute, but as soon as the needle would hit just over 180 it would come on without any doubt to anyone less than 100 yards away!
And you could get mesmerized just watching the gauge bob up and down, dancing around that 180 mark as the fan cycled on and off. Even at idle!

Even at 205 I can't tell any difference with the Explorer stuff.
You have a plastic or steel fan?

Paul

 

[toddz69]

Haven't noticed a distinct change on mine even at higher temps Todd. But I do think it runs at least partially all the time. Never really disconnecting fully.
I didn't think much about that though, as most fan clutches I've ever had had quite a big of drag to them even when cold.

Now, my brother's '66 Corvette fan acted like a secondary jet engine linked directly to the temperature gauge. Dead silent one minute, but as soon as the needle would hit just over 180 it would come on without any doubt to anyone less than 100 yards away!
And you could get mesmerized just watching the gauge bob up and down, dancing around that 180 mark as the fan cycled on and off. Even at idle!

Even at 205 I can't tell any difference with the Explorer stuff.
You have a plastic or steel fan?

Paul

I have the plastic fan. Yeah, it's running all of the time, it seems, although at a reduced speed, I think.

I have memories of the fan on our '77 F250 making a huge roar when it locked up and I can hear it engage on my Super Duty too when it warms up. On the old F250, you could watch the gauge go down too. On the Super Duty, our 'gauges' are just electrical switches to the best of my knowledge so the gauge doesn't ever really move unless you're in trouble.

So you're saying your truck gets to 205 and you don't hear the fan lock up? How are you seeing the 205? Aftermarket gauge with a lot of granularity or just squinting with your eyecrometer at the stock gauge?

The reason I'm asking is because my truck has gradually run warmer and warmer over the past 6-7 years (as best as I can recall) and it's now where it ran between 200-210 on Friday with max ambient temps of 109-110 and it got to 204-205 yesterday with max ambient temps of about 109. Not a lot of climbs at that temp - just running down the freeway at 65-70. My stock gauge in the cluster is reading 190'ish the whole time while my mechanical Autometer Sport Comp gauge is the one that measures in 2 deg. increments that I'm constantly watching.

Now I know that's technically not overheating but it's the trend that bugs me. Broncobowsher and I have been chatting offline with some thoughts - just trying to be scientific and reasonable about our thought process.

Todd Z.

 

[bronconut73]

Definitely subscribed....

 

[broncodriver99]

I don't have any info on the Explorer clutch but am running the Jag fan clutch setup which should be fairly similar. When really cold or in hot slow traffic the fan does make some noise but most of the time when cruising I think it is more of a gradual spool up instead of an on/off action. As mentioned I don't think they ever really disconnect but simply slip the viscous drive.

It sounds like your clutch may be failing. Is there any fluid around the hub? They can leak their oil. There should be some resistance to spinning it when the truck is off, if it free spins it is bad. Other than that I am not sure what other symptoms they may have when failing.

 

[broncodriver99]

Just looked around on rockauto and it should be a Hayden #2841. Their spec says it should engage at ~170 degree air temp.

Here is some info from Hayden.

http://www.haydenauto.com/upload/haydenauto/documents/cat_hayden/2007-hayden-fan-clutch.pdf

 

[toddz69]

Yes, I've read through Hayden's materials as well and my fan doesn't really display any of the 'failure' symptoms they describe. I do have a spare clutch (purchased brand new a few years ago) that I might put on the truck just to try out if I have the time.

Todd Z.

 

[904Bronco]

Paul's Bronco has a brand new fan clutch and Fan... (ok, maybe 5K on it) Old one was cracked.
Thermostat is 192*, so 205* is well within the range. Brand new WH replacement 3 core Rad. There is BCB A/C as well. He has Auto meter electric gauges... (my former rig) Aluminium fan shroud, with about 1/2 the blades out.

I have not heard Explorer fans do what you describe Todd. With all the wind noise associated with a Bronco, it is difficult...
Now my 02 F250 7.3 definitely lets you know that it has kicked in

Regarding gradually increasing temps, could anything else in the cooling system be suspect?

 

[B RON CO]

Hi, I didn't think the fan and fan clutch assembly we're doing much at highway speed. Seems like yours is pretty normal as for drag, smoothness, no vibration, etc. Did something change like tires, GVW or ? Maybe check the timimg and advance. I know a product like water wetter helps. I would check out the mechanical things first. Good luck

 

[Viperwolf1]

There is an alternative to the steel explorer fan clutch. It's a 4 Seasons part #46049. It pulls more air at all speeds than the stock clutch.

http://classicbroncos.com/forums/showthread.php?t=269694&highlight=serp+fan+clutch

 

[toddz69]

There is an alternative to the steel explorer fan clutch. It's a 4 Seasons part #46049. It pulls more air at all speeds than the stock clutch.

http://classicbroncos.com/forums/showthread.php?t=269694&highlight=serp+fan+clutch

Thanks Viper - I remember reading that thread last year.

I did another quick scan of it and it appears that model pushes the fan into the shroud about 1" more? Mine is currently positioned about what I would consider 'perfect' in terms of amount in/out of the shroud. The clutch I bought a few years ago and put on the shelf is considered a 'severe duty' unit iirc.

Todd Z.

 

[toddz69]

Paul's Bronco has a brand new fan clutch and Fan... (ok, maybe 5K on it) Old one was cracked.
Thermostat is 192*, so 205* is well within the range. Brand new WH replacement 3 core Rad. There is BCB A/C as well. He has Auto meter electric gauges... (my former rig) Aluminium fan shroud, with about 1/2 the blades out.

I have not heard Explorer fans do what you describe Todd. With all the wind noise associated with a Bronco, it is difficult...
Now my 02 F250 7.3 definitely lets you know that it has kicked in

Regarding gradually increasing temps, could anything else in the cooling system be suspect?

Yes, my 01 7.3 SD makes the same noise when it kicks in . I think the Explorer fan should also do the same thing but perhaps the air temp coming through the radiator at that spot isn't high enough for the clutch to engage.

Your last question is the one that's been rattling around in my brain for the past number of years.

As an engineer, I'm always thinking, "what changed?" And in this case, not much that's obvious to me anyway.

Changed radiators at some point from HD 3 core (locally made unit) to WH staggered 4 core because the 3 core material wasn't available anymore. But I think the temp rise had started before that change.

No engine modifications during that time. I did change a distributor or two for various reasons but I started with and still have 12*BTDC timing - been that way since '97.

The only obvious change is that I've changed trans cooler configurations. I went from a Super Duty trans cooler ~1" thick at the bottom of the core support to a 2" thick Setrab unit mounted higher in the airflow. I've been real tempted to move that thing out of the air path but then I come back to the obvious that the average temp has gone up with that thing in the same location for ~4 years now.

I've done several cooling system flushes with various products and the coolant gets changed pretty regularly because I'm always pulling my radiator out for one thing or another.

Water pump is the same one since '05 front dress swap (I think it's a Motorcraft unit) and it doesn't have a huge # of miles on it (maybe 60-70K max?). It doesn't have any leaks or shaft wobble to it.

What I haven't done is any compression testing, leak down testing, or chemical testing to see if those turn up any issues. Blackstone Labs analyzes the oil at every change and has never noted anything amiss.

Todd Z.

 

[toddz69]

Hi, I didn't think the fan and fan clutch assembly we're doing much at highway speed. Seems like yours is pretty normal as for drag, smoothness, no vibration, etc. Did something change like tires, GVW or ? Maybe check the timimg and advance. I know a product like water wetter helps. I would check out the mechanical things first. Good luck

I've used Water Wetter on at least 2 separate occasions with no reduction in temps that I could tell. Tires are actually a little smaller now, although the tire/wheel assemblies are slightly heavier than they once were. I've added a Warn M8000 winch up front but it doesn't disturb the airflow much.

Timing has always been 12* BTDC ever since I installed the EFI engine in '97. Computer handles the advance.

Todd Z.

 

[MarsChariot]

Todd,
Interesting question. I know that the fans on Explorers definitely "came-and-went" with a definite off and on sound, as I heard a friends Explorer doing that when it was idling in the driveway. Now that I think about it, so did the first Explorer clutch on the Chariot. That one came off a junkyard Explorer and was stock original. But the new replacement I do not recall hearing it do that. The original one could be spun by finger when at rest and it would turn several revolutions. The new replacement is so stiff that it spins maybe once. I thought that it might free up with time, but if so, it needs more time. It may be that the replacements are just stiff and spin pretty much all the time, so the difference between engaged and not engaged is less noticeable.

 

[DirtDonk]

While I have not heard the distinct roar associated with the fan locking in, there have by no means been any heating issues. Even with the A/C going full the engine has never run hot (even on coolish days the body gets a lot of heat transferred through it) and only gets into the 200 range when it's pretty hot outside.
When it was 110 here a week or so ago and I was running the A/C pretty much constantly (obviously!) I still never heard the sound, but the engine temp was consistent.
IN fact it's been very consistent. It always runs at 180 on cool days, just a tick/needle width above 195 on the hot days, and when really pushed it might creep up to the 200-205 range for a few minutes. It does come down, but I don't hear it in the fan.

Then again, this particular Bronco is pretty darn loud most of the time. It's still a hollow shell with Dynamat in some key areas, but not throughout. Maybe I just can't hear it kick in?
But no heat issues with the engine that's for sure.

Paul

 

[js521]

I'm running a 96 Explorer 5.0 with the steel clutch fan. On a trail run a few weeks ago I could here the fan engage right at 200 degrees. Would only run for a short time.

 

[toddz69]

While I have not heard the distinct roar associated with the fan locking in, there have by no means been any heating issues. Even with the A/C going full the engine has never run hot (even on coolish days the body gets a lot of heat transferred through it) and only gets into the 200 range when it's pretty hot outside.
When it was 110 here a week or so ago and I was running the A/C pretty much constantly (obviously!) I still never heard the sound, but the engine temp was consistent.
IN fact it's been very consistent. It always runs at 180 on cool days, just a tick/needle width above 195 on the hot days, and when really pushed it might creep up to the 200-205 range for a few minutes. It does come down, but I don't hear it in the fan.

Then again, this particular Bronco is pretty darn loud most of the time. It's still a hollow shell with Dynamat in some key areas, but not throughout. Maybe I just can't hear it kick in?
But no heat issues with the engine that's for sure.

Paul

Thanks Paul - and yours is even a 'worse' configuration than mine in that it has the evaporator in front of the radiator. Your engine's behavior is pretty much how mine was for years. Ran in the 180s in cool weather, 190 or low 190s in the summer and might hit 200 for a short bit on the longest/toughest climbs.

Todd Z.

 

[toddz69]

I'm running a 96 Explorer 5.0 with the steel clutch fan. On a trail run a few weeks ago I could here the fan engage right at 200 degrees. Would only run for a short time.

Thanks for your data point! Someone who's actually heard the fan lock up at a certain temperature. And when the fan kicked in like that, how much of a dip in operating temperatures did you see?

Thanks,
Todd Z.

 

[DirtDonk]

Also have a low profile winch, so we can add that in common as well.
Over the years, it's entirely possible that the sending unit and/or wiring have had some changes internally. Or the gauge itself even.

Seems like it would be more likely to be the engine just running a bit hotter, but the instruments are imperfect as well.
And speaking of smaller tires... You said heavier and smaller? What about engine rpm into the equation then? If you tend to go at the same or similar speeds, but the engine is turning a couple of hundred rpm more, maybe that's all it took.

Paul

 

[toddz69]

And speaking of smaller tires... You said heavier and smaller? What about engine rpm into the equation then? If you tend to go at the same or similar speeds, but the engine is turning a couple of hundred rpm more, maybe that's all it took.

Paul

Engine rpm is about the same as my 'smaller' tires are very, very close to the ones I had before. The previous ones were 35" Goodyears on 15" Ford Alcoa rims. I now run metric-sized 17" Toyos that are about 34" in height on 17" Circle Racing wheels. When I first got the Toyos, I put them side by side with the Goodyears and they seemed to be almost identical. I know that with wear, etc. that they're a little shorter now. Interesting observation, aside from any cooling considerations, is that I can get further up hills now before the trans downshifts out of OD with these tires and wheels than I could with the Goodyears. At first, I thought it couldn't be possible because the tire/wheel combo is most definitely heavier and I didn't feel like I had any gyroscopic effect that was helping. It must be the slightly smaller diameter of the assembly that allows that to happen.

Todd Z.