[Z09B4U]

Exactly what I was about to say. SEO 9C1 included RPO V08, using a mechanical engine-driven primary fan, and electric secondary.

Thank you for clarifying, regardless of the snark.

Apologies for the snark I pasted the wrong quote by mistake.

 

[GoremanX]

Reason I asked is because my 96 RMW (LT1 with tow package) and 93 RMW (L05 with tow package) both have a mechanical fan, and it's been remarkably reliable. Seems like a thing that would've made sense on a 9C1 car.

 

[Z09B4U]

GM was still using PCM controlled mechanical clutch fans on some platforms in the 2000s. On newer applications they seem to be used when the grill/radiator are too small.

In the search for ultimate MPG the mechanical fan adds more drag than a electric. Somewhere I found a link where they used a dyno to prove the 10HP drag of the mechanical on a LT1. The electrics do not use as much.

 

[GoremanX]

I don't doubt that at all. But when it comes to engine durability, nothing beats a mechanical fan. Not just because of the constant flow of air over the radiator, but also because of the constant flow of air over the engine even when the fan isn't needed. I'll gladly take the minor HP and MPG hit to improve the reliability and life of the engine. Both my RMWs are approaching 200k miles with their original powertrains

 

[Marky Dissod]

Didn't cops (9C1) and cabs (9C6) have a mechanical primary fan and electric secondary fan?

LT1 Caprices and RoadMasters with 2.93 GW9 got V92, which included a V08 mech fan and a 240W electrical secondary fan.
Some VERY EARLY '94 Fleetwoods (but not all) with 2.93 GW9 also got V92, which included the V08 mech fan and a 240W electrical secondary fan.

Once V4P became available in mid-'94, only Fleetwoods with V4P got 3.42 GU6 and the V08 mech fan and a 240W electrical secondary fan.

All weaker geared Fleetwoods got V03, two electrical fans.

All L99 Caprices, and all LT1 sedans and wagons with 2.56 (GM8) or 3.08 (GU4), got V03, two electrical fans.

However, 9C1 secondary fans were uprated from 100W to 240W until late-'96 (by which time GM didn't give a schidt).

 

[GoremanX]

Yum, alphabet soup 🤤

 

[Marky Dissod]

With GM OE fan-on thresholds, the V08 mech fan starts cooling long before the V03 electrical primary fan does.
The V08 mech fan very rarely if ever needs any help from the 240W secondary electric fan.

Think of the V08 mech fan as a 7,457 Watt primary fan that can alter its fan speed progressively (only costs 10 horse @ 5000RpM), whereas the V03 150 Watt primary electrical fan is an On / Off affair for B- & D-cars.

With reprogrammed fan-on thresholds, V03 cars behave more like V92-V08 cars in terms of temperature control, especially in stop-n-go traffic.
However the secondary electrical fan may come on more often (how often depends on several factors).

 

[Jimpala95]

A nice advantage with the mech fan 94-96 cars is one can easily switch between 160 or 180 stat without having any fan programming needed. I just returned from a 1,200 mile road trip down south and back to Chicagoland. I normally run a 180 in my 94 B4U. But for the trip temps were forecasting mid high 90's so I swapped in a 160. Worked nicely to shave off easily 20 degrees. With a stock 180 my LT1(stock) runs operating temps 9-14 degrees higher than 180 rating,depending on outside air temps and traffic.Ditto for the 160,car runs cooler over same conditions.9-13 over stat rating,temps taken with good temp gun. That all said,I do notice if I run a 160 over winter months the heater is a pinch cooler not piping hot like with the 180.
Jim

 

[AP9]

GM was still using PCM controlled mechanical clutch fans on some platforms in the 2000s. On newer applications they seem to be used when the grill/radiator are too small.

In the search for ultimate MPG the mechanical fan adds more drag than a electric. Somewhere I found a link where they used a dyno to prove the 10HP drag of the mechanical on a LT1. The electrics do not use as much.

Could this be why the Fleetwoods with the V4P trailer towing package are sometimes cited as 250 bhp & 310 lb-ft torque? I find it hard to believe that those engines truly would have been downrated.

I do remember now reading multiple times in the past that 9C1s had dual electric fans but with the 240W secondary....not sure why I keep thinking they did have the mechanical fan.

Sorry for straying further off topic here....

 

[Marky Dissod]

Could this be why the Fleetwoods with the V4P trailer towing package are sometimes cited as 250 bhp & 310 ft-lb torque? I find it hard to believe that those engines truly would have been downrated.

The V08 belt driven mechanical fan 'costs' are commensurate with the figures you cited.
(A plastic mech fan upgrade from a younger Gen3 V8 costs less horsepower than the metal fan, by the way.)
Note that the same parasitic loss also applies to RPOs V4P & V92.

 

[PURPLEPEARLCAPRICE]

Looks very clean under the hood. I'd verify correct fan operation first.
1. While engine is running, temporarily unplug the temperature switch and both fans should turn on within seconds.
2. When the vehicle is warmed up, turn the A/C on. Assuming your A/C is in proper working condition, one fan should turn on if you're at idle or driving at low speeds.

Let us know how the flush goes, would be curious if this was all caused by junk in radiator/block/core.

I'll keep you guys posted!...I'm going through everything all new hoses the 160° after the water is crystal clear...I'm even planning a new tank as well!... everything has been fine...I'm almost positive it was a air pocket in the system but I planned on doing all this anyway.

 

[Marky Dissod]

... even planning a new tank as well!

Had an early '94 radiator and / or reservoir, I'd try to keep it / them both at all costs, if at all possible.
Burping the LT1 cooling system is much easier using the hose between the radiator and the reservoir, than that 'bleeder' that sits on top of the Opti-.

... almost positive it was a air pocket in the system ...

Burp the system several times over the course of, say, a week or two, just to be sure.

 

[PURPLEPEARLCAPRICE]

Had an early '94 radiator and / or reservoir, I'd try to keep it / them both at all costs, if at all possible.
Burping the LT1 cooling system is much easier using the hose between the radiator and the reservoir, than that 'bleeder' that sits on top of the Opti-.Burp the system several times over the course of, say, a week or two, just to be sure.

I appreciate the heads up...tank is original and I'll have to take a closer look at the radiator...my cars build date is 3/94... whatever benefits the car I'm all for it...it's my baby and you don't see too many on the streets here where I'm from especially in the condition mine is in...alot of the ads I see out here they are all clapped out.

 

[Marky Dissod]

It's painfully obvious that your radiator and reservoir are 'original' BECAUSE they share a direct connection.
Try to replace either, you'll find that 'new' reservoirs and radiators can no longer connect.

Change the coolant every two years (maybe add some RMI-25 - google it), you'll be able to keep either the radiator, the reservoir, or better yet, both.

 

[Z09B4U]

How to get rid of Dexcool (long) - Chevy & GMC Vans

Citric acid Mercedes coolant flush (thought vomit)

While this is kicking around in my head as something that I want to do soon, figured I would post it here for others to see.. I have already replaced the thermostat and housing gaskets last year. To remove oily residue from cooling system: disodiumtrixosilicate-pentahydrate. Part number: A...

www.benzworld.org

 

[Z09B4U]

The down side to actual cleaning is the gunk may be plugging a leak. Do not be surprised by a leaking rad or heater core after a good cleaning.

 

[PURPLEPEARLCAPRICE]

This car has a build date of 3/94...has the green coolant thank God....being in my profession I have access to everything and even got accounts with all major parts stores ...I do all my fluids once a year and my fuel filter once or twice a year and several other things I do (I'm extremely anal when it comes to maintenance on all my vehicles)....I just picked this car up Easter Sunday and I did a few things so far but still got alot more to go!