[OFB Cafe] Engine overheating

[Rick Bowers]

At Wednesday 7/16/2008 12:29, you wrote:


>--------------------------------------------------
>From: "Peter Hollings" <PeterHollings at Comcast.net>
>Sent: Wednesday, July 16, 2008 7:08 AM
>To: "An Open Discussion Forum on Just About Everything,Especially for
>Techies." <cafe at ofb.biz>
>Subject: Re: [OFB Cafe] Engine overheating
>
> > I think the fan clutch is a better explanation. Also, it is cheaper.
>
>It's a better solution, I don't know about explanation.  And viscous fan
>clutches aren't cheap, but by the time you get done fiddling around wiring a
>power supply to a relay, then from the relay to a fan motor, find a spot in
>the intake manifold to screw in a temp sender for it, figure out a way to
>mount an electric fan and shroud on a big cross flow radiator (I assume this
>is Rick's Durango with the 360 in it), you can just put the new clutch in
>and be money ahead.

Yes, I tend to agree. I was wondering if the electric fans had any 
specific advantages. Obviously, not.

>You can replace the clutch yourself too.  I don't remember if the Mopar 360
>has a bolted hub or threaded, but I think its threaded.  Leave the belt on
>the pulley, and with an air chisel, bite into the front side of the big nut
>on the clutch hub (the hub is LH thread so you have to turn it the opposite
>direction - clockwise - to screw it off the water pump shaft), and squeeze
>the trigger on the air chisel to break it loose.  The 360 in a Durango is a
>tight fit so you have to take the bolts out of the fan shroud and move the
>shroud to get the fan and clutch assy out.  And be careful that you don't
>nip any radiator cores with the fan blade when pulling it out.  Those
>radiator cores are fragile and its pretty easy to put a hole in one if you
>don't watch what you're doing.

Yes, it's my Durango/360 and, yes I've replaced these before. The 
fan/clutch in my '74 'Cuda mounted to the water pump with 4 bolts. 
The 360 in my Durango uses a single, threaded nut. A poor design, if 
you ask me. But I'm sure it's cheaper for Chrysler to build.

The whole problem started about two years ago. My water pump went 
out, so I went out and bought a new one. I couldn't get the fan 
assembly off (don't have an air chisel) so I thought I could remove 
the water pump/fan assembly as a unit and deal with it out of the 
car. It turned out there wasn't enough space, with the fan shroud 
loosened, to pull the assembly out.

It was winter, and I don't have a garage, and I was under some time 
constraints, so I brought the Durango to a mechanic. It turns out he 
was a dishonest mechanic. I told him I couldn't get the fan off and 
needed the water pump replaced. I already had the new water pump.

When I picked up the Durango, the invoice was about $380! He CUT the 
fan off (doh! *I* could have done that if I'd wanted to) and charged 
me for a new one. The price was way too high, but I paid it and vowed 
not to go back to him again.

Two days later, the water pump was spraying fluid everywhere so I 
took it back to have it fixed. That night, when I picked it up I got 
another invoice for over $300! He told me all the hoses had to be 
replaced. Ummm, if they were that bad, why weren't they replaced the 
first time? Anyway, I told him where he could stick that invoice.

The second time I took it to him, I was waiting for my ride and he 
mentioned he couldn't make a living off just repairing cars so he 
sold parts, too. I'm guessing rather POOR parts -- so now I need to 
replace his crappy clutch!

>After you get it out, unbolt the fan from the old clutch and inspect the
>fan.  If it has any cracked blades, replace it (a busted fan blade @ 5,000
>rpm will blow the shroud right off the radiator and come thru the hood).  To
>tighten the fan hub, assuming you don't have a fan hub wrench, you can grab

I'm not clear on this part. Do you mean tighten the fan/clutch 
assembly to the water pump?

>the nut with a big Channel Lock pliers with the movable jaw to the
>counterclockwise side of the nut.  Then hit the handle of the moveable jaw
>with a rubber mallet a couple times to snug it up.  The clutch hub will self
>tighten under normal operation and won't come loose because it takes quite a
>bit of power to run the fan - if you tried to run that fan with a 5 hp
>Briggs and Stratton lawnmower engine you'd only get it to about 2,600 rpm.
>--
>Chris
>
>
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