Eureka!.......it was the fan clutch all along!......

The lack of "fan roar", as described on this site, made me suspicious that I had a clutch problem.....

Swap-out was fairly routine, took about 2 hours....For the eight 1/2" nuts involved, I recommend a flat "box ratchet" wrench...standard ratchet socket & handle won't fit, and regular box wrench keeps you sprawled-out over the air cleaner/pillow too long...

Took a spin the the Interstate....90 degrees ambient....needle barely got to center mark....could hear fan kick in & out....Life is good! Radiator is original, so a replacement is on the list, but at least it's useable for now.....

Thanks to all for the feedback

....and Billh, after inspecting from every possible angle, I'll bet you a pair of fuzzy dice that I've got a one piece shroud...Sometime after '78, they must have decided on a better approach and split it.....

Lee What is the part number of the fan clutch? Were you able to get it at NAPA? I'm sure that mine is bad. Dennis

Don't have NAPA number, but:

clutch is from Four Seasons, 1801 Waters Ridge Drive, Lewisville, TX, Part #36704 (For a '78 P-30/454) {no website found}

They "claim" it meets or exceeds OEM....Only time will tell, but at least I'll now know what to listen for when it dies......"retails" at $125, but my retail parts source charged $79.00 - who knows what the things are worth?.....

Regarding 454's, over-heating & fan clutches, there's a good thread at:

http://www.rverscorner.com/info/manifolds.html

Glad you are cooler now. However, I fear that the fan kicking in while level cruising in 90 degree ambient indicates the radiator is still a little hot. Right now, the fan is compensating, but I wonder how things will go uphill with a toad. Are you using 50/50, WW or what? Was that with dash air on? Do you have a trans cooler?

Maybe I am doing the overkill thing here, but anyone who has towed up Chriaco, Sherwin or Montezuma in summer will nod.

Billh, I agree with you on all counts...It's incremental progress, and I've still got a ways to go. In my favor, the unit is only 24 foot, used mainly for traveling up & down the east coast flatlands, and lightly loaded for civilized camping for two. Here's the plan:

1. install a mechanical temp gauge so I can work with real numbers rather than guess at relative indications of the OEM gauge......

2. After this season, R&R the radiator, going with your US Radiator recommendation.

3. Dash air is coming out (physically) so I can get to plugs in that corner. (My shop is fabbing-up a new idler assembly to take the compressor's place so I'll have a tensioner device & use standard belts.) The a/c evaporator can then be removed from front of radiator, unloading some heat load.

4. Install deep tranny pan with cooling tubes to help unload front cooler....

4. I'm running about 15% anti-freeze with WW....Just gotta remember this fall!

This will get me through this summer, with things to do over the winter.........

Any other suggestions?

Lee, it sounds like you have a good handle on it. In fact, you are ahead of me on the idler pulley to replace the dash air compressor. Gonna do that sometime. I would be interested in any info your shop would share on that. That will also help with my doghouse lowering program.

As for your tranny pan, the one you have may already be the deep one. Most P30s had one much deeper than the automobile pan. I have been afraid of leaks with the tubes running through the bottom. My tranny man says they sometimes leak.

Being a 24 footer, you shouldn't have too much heating, particularly with your driving.

I now too have the fan roar that I have been missing. I went to the local auto parts store and found a fan clutch. It is a Hayden. I called the Four Season's in Texas and they told me that they make the clutches for Hayden. Thanks for the help.

Too late for Dennis & me, but I picked-up a tidbit from a self-professed fan clutch guru that I wish I knew before I swapped-out:

According to him, bug guts, road oil & other crud builds-up all around the spring thermostat on the face of the clutch, rendering it inoperative as to temp sensing & hub lock-up......A solvent cleaning and air blow-out of the spring area will, in many cases, restore clutch to full operation......

Maybe true....maybe not, but before buying a new unit, it would be simple enough, via mirror & Braille, to clean-up the front spring on the existing clutch without any disassembly and give it a try.....I know my old unit was indeed full of crud between the thermostat windings.... But now that I have a new unit installed, there's not enough money involved to pursue it any further....Next time though........

Lee, Thanks much for the info on cleaning the fan clutch. I had never heard the roar everone is talking about when you first start up the 454, so last night I used a tooth brush with a little detergent and water, cleaned the little thermostat in the front of the fan.
I started the Barth up this morning and by golly I heard the fan kick in for a couple of seconds. I'll have to wait until it I get on the road to see if it functions properly

THANKS AGAIN
RALPH GLOVER
1976 27' BARTH

The bug and crud buildup will definitely impair heat transfer, but even my clean clutches seem to fail a few years down the road. Heck, I even give them a light coat of flat black to improve heat transfer.

Duteman, I would be interesting in hearing more on why you think Delvac 1 is better than Mobil 1.

If I had the one piece shroud, I would have to make it a 2 piece with some aluminum L's. I would use a cutoff wheel and cut it in half, then pop rivet the L's on the shroud so that they mate together. Screw it together with bolts and wingnuts. Even with a divided shroud, it's a bear to get out.