***SOLVED***Within the thread it was determined that the clutch is leaking fluid which indicates a failure. Researching a replacement, I discovered that it appears highly likely that the pricey Delco replacement is manufactured by Hayden, who also makes the other versions sold by Napa, Autozone, O'Reilly's and perhaps others. Some may be made in China. The Murray (Hayden) I found at O'Reilly's is clearly the same mold as the Delco unit. Both say "MADE IN USA." Delco/Murray(Hayden) comparison here with an immediate followup post with more thoughts and details.Original Post begins here...On return from our last outing, the fan clutch would engage as usual, but remain engaged much longer than usual and eventually disengage at lower than usual temp gauge readings. This appears to be an atypical type of fan clutch failure.I removed it today and noticed some grease and gunk in the bi-metal spring.In researching the subject I came across some interesting thoughts in this thread.1. The thing could be the 30-year-old original with 105,000 miles. I figured it was due anyway. However, some GM and fan clutch folk appear to believe that these things very rarely fail and are often replaced needlessly.2. Is the gunk around the spring acting as a blanket to heat the spring prematurely and keep it warm well after it should have cooled?3. Where did the gunk come from? Is it a leak of silicone from inside the clutch that's trying to tell me she's not long for this world?4. If it needs replacing, is there a preferred replacement unit?EDIT: On pg 2 I pointed out that the story is 8 months old and my recollection may not be perfect. So I removed the part in the first paragraph of this OP where I had said I thought the clutch engaged at lower temp gauge readings than usual. However, I am very certain that it took much longer to disengage and at lower than usual temp gauge readings.I also posted a photo on pg. 2, so I'll post that here too. Note that there is grime on the clutch, but only the spring is "wet."

Normal. I used to fly in Super Constellations (Electra jet) and used to laugh that they sounded like a Chevy 454 fan clutch. A bit of oil is normal. Fan spins logie when cold by hand but very tight when hot. Two varieties of replacements and everone chooses the cheap garbage one. The good ones ain't cheap McGee.Ignore it or turn up the radio ;)

Clean the thermal spring and try it. Mine wasn't working at all, I replaced it with a Hayden Severe Duty Model.

I would rather have your problem then the one where it doesn't workYou do realize that these thing work like a torque converterAnd the thermal spring controls a valveIf you are going to replace it, get the severe duty modelAnd the seven blade fanThey move a lot more air than the five blade models

MEXICOWANDERER wrote:Ignore it or turn up the radio ;)Oh, I have no problem with the fan noise. It's reassuring, actually.But the issues is that now it is definitely coming on way too early and remaining on way too long. I've driven this rig for 10 years now. I know her her like my the back of my hand.And Wiz,Yes. I understand how it works.I completely agree that it's failing in the right direction. Believe me, that is not lost on me in the least. Nor was it when it began to behave this way when I was struggling to return home with a failing distributor. Except that it was squealing the belt if I went over 50 which is right where she would begin to run ok with said failing distributor. That was quite a dance... until it was time to pay the piper.Now if it IS failing... then how do I know it won't fail in the WRONG direction... when I'm 6 hours from home.... with my wife and kids little ones in the rig... pulling the boat... on a long and lonely.... hilly... HOT desert road?I would definitely opt for the severe duty. And I believe it's a 7 blade. Perhaps the previous owner did the mod. They did a number of appropriate mods and took good care of her. But I'll look next time I'm over at the storage yard.I've read good and bad about Hayden. I'd say mostly good.I can say the same about the OEM. And given GM's rep following the bankruptcy... I'm no longer inclined to default to GM parts without a little research at least.Do you guys have any opinions on Hayden and or the GM clutch?

It sounds to me your fan clutch is working and working well. I cleaned mine with a tooth brush and some electrical cleaner. I was trying to my mine come on earlier thinking the dirt would insulate the spring. On the older model P30's there may be 2 or three slots to insert the end of the spring to adjust when it will engage mine only had one slot. Your radiator if original my be partially blocked or just needs to be flushed, and the fan clutch is doing what it can to remove the heat. Your thermostat can be failing to open all the way and again you fan is working harder to compensate. I would check your radiator first, look for debris between the AC condenser and radiator look for bugs dirt build up on fins clean if necessary. Check thermostat in boiling water see if it opens a 1/4 in I have seen tstats open only 1/8 in right out of the box. Check you radiator for cold spots indicating a blockage. See what you delta T is from input to output of your radiator. Try the simple things first before you change the fan clutch.

***SOLVED*** '86 P30 Overzealous Thermal Fan Clutch

MEXICOWANDERER
Explorer
Apr 18, 2016

HAYDEN 2797 Thermal Info
Standard Rotation Severe Duty Thermal Fan Clutch; Fan Mounting Holes are 5/16

$42.79
KendallP
Explorer
Apr 17, 2016
So I found more and more recent threads with happy Hayden customers. And since no one local had the Delco unit in stock, I thought I'd take the old unit down to O'Reilly's, along with my trusty scale. Right off the bat it was apparent that the Murray (Hayden) 2797 was notably smaller in diameter than old Betsy. The weight was a little lower, but my guess was... proportionately so, i.e. the new one weighed about what I would have expected given it's smaller overall size. Granted I didn't have my abacus and slide rule with me, but I felt we were in the ball park.

Then... as I was contemplating all of this... I saw it.......

"MADE IN U........ S.............A!!!!"

Hoodathunkit!

"Lifetime warranty, right?"

"Yep."

"Here's my card."

The patent number shown in the photo below belongs to Standard Motor Products. It would be real interesting if that same stamp showed up on the Delco version.

Got her home and calibrated my scale with a dumbbell I borrowed from MEXICOWANDERER. Then took some measurements for my adopted grandfather, here. I estimated the volume of each of these discs (cylinders) to be...

Old - 62.54 ci
New - 53.69 ci

The new one has 85.85% the volume of the old

And the weight?

Old - 60.3 oz
New - 51.3 oz

Percentage.......

85.07 (or 85.1 for you significant digit fanatics)

What does this all mean?

No idea. The new one is definitely less massive, but the densities appear to be similar.

I'm still hopeful I can find the Delco locally for comparison. Otherwise I may order one. However...

Interestingly enough, the Delco unit on Amazon comes with the following disclaimer:

"Note: ACDelco partners with other manufacturers to supply the parts your car was originally built with. This product is in an ACDelco package, however the part may have been manufactured by an independent ACDelco supplier and could have a different color or shape than the product image above."

Also... a guy in the questions and answers section on Amazon verified his Delco was the same diameter as my shiny new Murray/Hayden unit.

Picture time...

And note the last 2, which are screenshots of Delco's parts page when searching for their clutch for a 1986 P30 with a 454. The last photo is the closeup you get from clicking the thumbnail. It's visually identical to the Murray. Internally? That's anyone's guess, but there is evidence to suggest that they are identical in every respect.

First... 2 days worth of "weeping" while lying face down. Both are now sitting upright on the bench as though they were mounted on the water pump.

YOO-ESS-A!!! YOO-ESS-A!!!

Calibration using MEXICOWANDERER's dumbbell
KendallP
Explorer
Apr 15, 2016
MEXICOWANDERER wrote:
...You lived how many years without a complaint with the heavy duty OEM fan clutch? now replacing it with the same part number raises noise issues? Now stop and think: Do you Reeeeeally believe GM put a standard duty fan clutch on a P30 with 454 chassis?

Or are you going to keep trying to re-invent the wheel? :)

If you'd spend more time actually reading instead of defaulting to your favorite passtime of breaking your adopted grandson's huevos, you would know that the write up was NOT talking about the OEM, but rather a lighter duty Delco clutch that runs high when disengaged. THAT is why the guy likes that unit for the hot desert and THAT is why the unit is noisy... ALL THE TIME. Not just when engaged... LIKE MY BELOVED OEM!!!

I absolutely DO want exactly what GM put in there 30 years ago. Problem is... today ain't 30 years ago.

Found one at O'Reilly's. A Murray made by Hayden. It's exactly the same, visually as the Chinese Delco. I'll let you know what the scale says.
wolfe10
Explorer
Apr 15, 2016
Mexicowanderer,

Actually, you exposed a SECOND problem-- stuck thermostat.

130 degrees F. says the thermostat was stuck OPEN.
MEXICOWANDERER
Explorer
Apr 15, 2016
EXPERIENCE NOT CONJECTURE
1980 Vogue motorhome. 440 L3 engine. Bad level ground higher speed overheating problem. Owner would not believe it was his new fan clutch. Wanted a radiator. So I got him a new radiator. Custom built FIFTY percent more tube and fin area. An extra row of tubes (5). And substantially high fin count per inch. Oh indeed it helped, but 230 degrees was still too hot. I bet him a lobster dinner in Mammoth that the fan clutch was at fault. He sneered and yanked the fan and clutch off. Temperature plummeted ONE HUNDRED degrees. That's right, 130 degrees level ground no fan on a 95 degree day. I made him pay up. He had pork chops.

Stand behind one of those giant wind turbine generators on a windy day. You can flick your Bic and the flame will barely waver. A malfunctioning fan clutch can block airflow as dead as strapping cardboard across the grille.

You lived how many years without a complaint with the heavy duty OEM fan clutch? now replacing it with the same part number raises noise issues? Now stop and think: Do you Reeeeeally believe GM put a standard duty fan clutch on a P30 with 454 chassis?

Or are you going to keep trying to re-invent the wheel? :)
KendallP
Explorer
Apr 15, 2016
MEXICOWANDERER wrote:
"In the desert southwest the HD Delco is the only way to go"

What part of that PDF is confusing?

If you read on... you would see that he is strictly speaking of the disengaged RPMs. And more reading will tell you that the particular Delco to which he is referring... runs at like 80% RPM while disengaged and therefore is... essentially engaged at all times and loud as Hell while driving a straightaway in the snow!

Again... just a few of the many, many threads I have read and am still reading. Most of the guys over there do not use that clutch because it is too loud at all times.

MEXICOWANDERER wrote:
...Or do you value and trust other people's assumptions more than your own eyes and a scale?

Well I'm not sure I trust anyone on the phone from Hayden either. I was thinking of taking mine down to Napa, Autozone, Oreilly's and Carquest and doing some comparison, actually. And I do have a good scale that I trust and I HAVE BEEN LISTENING, Gramps.

:)

Only concern is their stock on hand.
.
MEXICOWANDERER
Explorer
Apr 15, 2016
"In the desert southwest the HD Delco is the only way to go"

What part of that PDF is confusing?

"Some of this and some of that are made in China". Some Honda engines are made in China. My DROK panel meters are made in China. Just because something is made in China does not automatically make it junk. It depends on production design and supervision. Nowhere can I find one single solitary suggestion (never mind words) that the heavy-duty Delco clutch is made within 500 miles of Hayden Products. The light duty GM fan clutch may be built by Hayden but NOT the heavy duty version. This IS WHERE you, armed with astute eyeballs and common sense have to compare the difference in design and weight between OEM and Hayden. Call Hayden. Ask them how much their fan clutch weighs. That should not be an insurmountable task. Compare their claim to a genuine GM clutch.

Or do you value and trust other people's assumptions more than your own eyes and a scale?
KendallP
Explorer
Apr 15, 2016
MEXICOWANDERER wrote:
Ooooooooo a waffler to rate right up there with the Blue Dress ex-president...

You gonna trade that sucker in, or not?

Hydraulic oil will migrate via gravity. Always stand upright the fan for 24 hours before spinning it.

Fans are sorta important. A wrecked motor is valueless as a trade-in. Monitoring a temp gauge all the time is tiring. An electric fan that is brushless with sealed oil filled ball bearings is hard to find.

You claimed that this fan is acting weird. You have a choice, do something or do nothing about it. It isn't getting any younger.

HOLY OVERASSUMPTION!!!

You got ALL that... from THIS???

"24 hours of lying face down after your Brakleen and no moisture to be found on that spring. Part of me has to wonder if the dollop I witnessed wasn't just the effects of gravity on the goop around the spring."

And I thought my wife and daughters were drama queens.

Isn't there a bottle of lithium with your name on it somewhere in that converted bus of yours? If not, there's got to be a farmacia close by.

I was the one who thought the moisture between the coils was from the clutch. My point was that it may be a slow leak and... perhaps... the dollop I saw was less new leakage and some of the old stuff dropping out... when other nameless individuals... currently residing in Mexico... were less concerned... until the dollop photo was posted.

Yes. I'm still looking for the best option. Was searching, actually, when I went to check back in to the thread.

I have done a LOT of research on this over the last several days. These times they have already made a changin'. It appears I am going to be hard pressed to find one I can be confident in... and that includes the OEM units made in Red China... and possibly as an outsource to Hayden.

Here are just a few of the links I'm in presently. But there are more. Many... many... many more.

The GMCforum boys have been working on this for awhile with quite a bit of testing done.

Hope our mods are more interested in knowledge base than those pesky rules. Though I don't recall ever having a problem in the 10 years that I've been here...

http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&goto=263245&rid=0

This guy has apparently done quite a bit of testing. Here's one of his write-ups...
http://www.gmcws.org/Tech/Engine_Cooling_System_Basics_-_Steve_Ferguson.pdf

And some back and forth saying Haydens suck and Haydens rule over the Delco that only lasted a week...
http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&th=35632&goto=291246&rid=0

What a world
MEXICOWANDERER
Explorer
Apr 15, 2016
Ooooooooo a waffler to rate right up there with the Blue Dress ex-president...

You gonna trade that sucker in, or not?

Hydraulic oil will migrate via gravity. Always stand upright the fan for 24 hours before spinning it.

Fans are sorta important. A wrecked motor is valueless as a trade-in. Monitoring a temp gauge all the time is tiring. An electric fan that is brushless with sealed oil filled ball bearings is hard to find.

You claimed that this fan is acting weird. You have a choice, do something or do nothing about it. It isn't getting any younger.
landyacht318
Explorer
Apr 15, 2016
I read these thermal clutches should not be stored on their back or face, After i once did so.

When re installed it was spinning full speed and making a huge racket, cold. One hot cold cycle and it returned to normal function. That was 10 years ago.

In the Overkill arena. How bout some large electric pusher fans in front of the radiator? Put them on a voltage booster and spin them at 20 volts. Add misters to help remove heat.

I always see claims of those removing the thermal fan clutch for electric fans and how much they love it, quieter, more powerful, more placebo MPG's too, but I never hear any longevity reports.