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radiator hotter than block on overheating fleetwood? [was: 93 fleetwood fans]

Started by dochawk, September 07, 2022, 09:20:40 PM

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dochawk

update:  at the end of page 6B-16, I found

QuoteThermostat Assembly Opening Temperature..... 83°C (181 °F)

but still no thermostat entry.  So when the sockets arrive tomorrow that fit the torque wrench that followed me here, I'll assemble without upper thermostat, and see both whether coolant flows when first turned on, and whether the engine stays at proper temperature without boilover.


Quote from: Daryl Chesterman on September 30, 2022, 01:40:24 AMhmm, when I exported the pdf to pdf in preview, I found that *some* of the thumbnail were simple page numbers in the pdf, and others were named pages.  So it *wasn't* OCR.

And for the record, although it took something like 45 minutes with fans blazing on a MacBook Pro, performance is *much* better on the exported pdf.  That, and I can add a bookmark and save without it going into death throes . . .

On what you are referring to as page 662 (shows 6B-9 in the upper right corner), in the lower corner above Figure 3, it says:

Install or Connect
NOTICE: The wrong type of thermostat assembly
installed in the thermostat housing assembly will
cause some engine coolant to only flow through the
bypass into the left end tank of the radiator assembly
causing insufficient cooling or possible engine overheating.
NOTICE: Make sure the thermostat assembly is
installed in the correct location. Installing the thermostat assembly in the intake manifold located on
top of the engine will cause excessive coolant pressure and possible overheating.
NOTICE: See "Notice" on page 6B-1 of this section.


I don't know what the "Notice" is on page 6B-1, but the above section does refer to the thermostat on the intake manifold on the top of the engine, and it possibly causing overheating.  I have worked on Chevrolet 350 engines and there was no thermostat on the lower-right front of the engine.  Could this engine have two thermostats?  According to NAPA's cataloging, the thermostat is supposed to be a 180°, and is supposed to have a rubber seal with a slot on the inside circumference of the seal that the rim of the thermostat should fit in, as well as a paper gasket.  Generally speaking, the spring side of the thermostat goes down into the intake manifold with the rim (with seal) sitting in a shallow recess, then the paper gasket goes next, then the thermostat housing.

According to Rock Auto, your thermostat should be a Motorad 7307180, which is a 180° thermostat.  So, I would not use the 195° thermostat.  Rock Auto's thermostat also shows the rubber seal around the circumference of the thermostat rim.  The diameter of the replacement thermostat should fit inside the recess in the intake manifold.  Does the section 6B-1 show the thermostat in the water outlet at the top of the intake manifold?  It sounds like you are going to have to sort out if there is also a thermostat on the front-right side of the engine, also!  I would also be very careful where there is a rubber seal around the thermostat, as well as a paper gasket, as it might cause too much thickness leaving a gap between the ears of the water outlet and the surface of the manifold and when tightened, bending the ears of the water outlet.  It is possible that you only need one or the other and not both.

Good luck!
Daryl Chesterman
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

dochawk

update:  at the end of page 6B-16, I found

QuoteThermostat Assembly Opening Temperature..... 83°C (181 °F)

but still no thermostat entry.  So when the sockets arrive tomorrow that fit the torque wrench that followed me here, I'll assemble without upper thermostat, and see both whether coolant flows when first turned on, and whether the engine stays at proper temperature without boilover.

1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

dochawk

Major success!

I took the thermostat in the upper housing completely out (rather than the 195F replacement that may not be the right diameter disk, anyway.  I'm suspicious).

When it got to 20 minutes running in the driveway without acting up, I added to the full cold line of the overflow tank, I drove 2 miles down the hill, and back up.  Still stable.

Then 7.5 miles largely downhill, and back.

Tank still at same level, and top of engine block reading about 183.

Tomorrow morning, I'll try the 20 miles and back that went wrong last week (to church!), and if that works, I can go home on Monday (it will be too late to drive back by the time things are settled after church.

However, I did this today without the AC on, as the secondary fan wasn't coming on.  I'll check fuses, and then if it works with a toggle, go that way.  If not, I suppose I drive home with the windows down . . .

I'll report late morning tomorrow.

For now, I've earned a beer.

Oh, and the only thing that I ended up using from the tools once they arrived was the 3/8->1/4 adaptor--it takes a long socket to do the posts that hold down the faux thermostat cover!
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

James Landi

Hi RIchard,

I haven't been closely following your post, but my "work around" approaches are of a similar genre to yours when apparently simple yet major mechanical challenges occur. So I'll add my 2 cents--- there's a fan module usually mounted under one of your head lights-- it's a transistorized component on most modern cars that's rather sophisiticated. The body control module or engine control module provides a low voltage "signal"  to this transistorized switch (the ones I know of don't have servo-mechanical switches)--- and more important: the "ground" for the fans is also controlled by the module--- the ground wire provides feedback for the computer so that when a diagnositic scan tool is used, the mechanic has several significant readings to assess the entire operation of each fan, its respective threshold for cycling on, etc. I just replaced one of these in my 1988 Cadillac and had been seriously considering using under dash toggle switches so I could make the "judgement calls."  Once I replaced the module (around 90 dollars), all is good.  Hope this helps and is informative.   James 

dochawk

I didn't find those modules--but then again, I didn't look very hard, either.  That's a job for when I get home and can order the module (if, in fact, it's the culprit).

It will generally be over 90 for tomorrow's drive, so the ac will be on, and the correct consequence is both fans running.

I shortened the leads on my toggles today, and remounted the base of the relay socket block, which should hold the toggles a little steadier, and prevent them from meandering from where I place them.

I think I'll add a tie-down as well to snug the spade lugs into the sockets.
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

James Landi

It certainly won't be concerning to run both fans, switched manually by the good doctor.  When I was living on a school teacher's salary and driving my '56 sdv during the oil embargo of '73, my heater valve developed an arterial bleed, so I replaced it with a house plumbing ball valve... suited my purposes just fine.  I could bore you with other "work - arounds," but suffice it to say that my "better 7/8's" often found them less then entertaining.   Happy day,  James

badpoints

I would just either wire both fans together or use the working control line for both relays.