mechanical fan clutch

[Darkbloodmon]

What about making one out of sheet metal?




It’s not the cooling capacity, it’s the airflow. The OEM radiator has plenty of capacity, just lacks airflow when the fan is failed or undersized.

Out of curiosity, what’s the volume of your cooling system with your radiator? It’s a Mishimoto, right?

I spent some time looking up at it thinking how I could fenagle it but the lower shroud is designed to drop into a slot on the Upper/main shroud with a channel for the harness. It's kept in place by plastic push tabs on the lower shroud protruding to the Upper/Main to hold it in place, there aren't any fixtures on the side of the radiator that low to mount a bracket too and hold the harness too. The rad has factory mounting positions for the OE shroud.

Air flow a side it a heat sink with water flowing through it, the larger fluid capacity is a larger heat sink alone before its run through a radiator. Larger fluid bodies take longer to heat up than smaller fluid bodies.

Yes its a Mishimoto unit 6.4g capacity, two row, 19 Psi system.

 

[BigPapa]

I’ll TRY to remember tomorrow to look at the fan clutch wiring on our buses. I’m pretty sure it’s mounted to the engine, not the shroud like the trucks.

 

[AH64ID]

I spent some time looking up at it thinking how I could fenagle it but the lower shroud is designed to drop into a slot on the Upper/main shroud with a channel for the harness. It's kept in place by plastic push tabs on the lower shroud protruding to the Upper/Main to hold it in place, there aren't any fixtures on the side of the radiator that low to mount a bracket too and hold the harness too. The rad has factory mounting positions for the OE shroud.

Gotcha, so you'd have to go full custom.

Air flow a side it a heat sink with water flowing through it, the larger fluid capacity is a larger heat sink alone before its run through a radiator. Larger fluid bodies take longer to heat up than smaller fluid bodies.

Yes they do, but you're not heating the whole system at once. You have a hot block, and very hot cylinders, heating up a smaller portion and mixing it with the fluid in the radiator. It takes no time at all to heat up the entire system under load.

Yes its a Mishimoto unit 6.4g capacity, two row, 19 Psi system.

6.4 gallon's just in the radiator or total capacity?

 

[Darkbloodmon]

Gotcha, so you'd have to go full custom.

Essentially, it'd be much more than what I did the first time to repair the crack in my shroud which was zip tie stich the crack.

Yes they do, but you're not heating the whole system at once. You have a hot block, and very hot cylinders, heating up a smaller portion and mixing it with the fluid in the radiator. It takes no time at all to heat up the entire system under load.

Aye, but for what I do heat hasn't been an issue.

6.4 gallon's just in the radiator or total capacity?

Doubt it but I haven't measured it. Looking at the FSM for the cooling capacity on a stock application its about 7.5 gallons for the total system. I'll check my logs and see how much coolant the system took when I cleaned it for a flush.

 

[Ozymandias]

Came back to this thread looking for part numbers and I can't seem to source the lower portion of the shroud. No superseded P/N, discontinued everywhere I look including Ebay. Saw a few trucks being parted in my area but people are asking crack prices for plastic just as old as the vehicle it came off of.

Same problem here, I'm looking for the upper, driver side, shroud bracket.
200$ upwards on eBay. Crazy.
No way I'm going to pay that.

 

[ranger 393]

I have been running a Mechanical fan clutch for several years here in Az with no issues. I have pulled my 43ft toyhauler all over Az and has never had cooling issues.
I havent noticed any change in ac performance.. Just my personal experience.

 

[BigPapa]

Here you go. The Fan Clutch wire has a red arrow pointing to it. Yes, I'm sure it's a totally different harness, but I don't see why you couldn't extend and/or reroute your existing wiring where it doesn't have to utilize the fan shroud.

 

[NIsaacs]

Different animal I think.

#ad

 

[Ozymandias]

Different animal I think.

Yes, the one from @BigPapa is a simple On/Off clutch whereas ours is a Vistronic.
I have to re-read this thread to find out what the actual question is...

 

[NIsaacs]

Yes, the one from @BigPapa is a simple On/Off clutch whereas ours is a Vistronic.

Yes, his, the wiring is behind the belt/fan, the Dodge is in front of them. Looks like it would be very vulnerable to hitting the fan, if anything went wrong.

 

[BigPapa]

Alright, showing my 3rd Gen ignorance, AGAIN.....

Is the Fan Clutch between the fan and the radiator on the 3rd Gen's, on the front of the fan?

 

[Ozymandias]

Yes, very much the same as the old viscous clutch before.
The wiring is feed up to the center of the fan along a metal rod from the lower left corner.

 

[BigPapa]

OK. I understand now. I didn't know the clutch was mounted like a viscous clutch. That does seem a bit crazy.

On our buses, they either have the hub mounted electrical clutch or an old school viscous clutch.

Sorry for my ignorant confusion....

 

[Darkbloodmon]

OK. I understand now. I didn't know the clutch was mounted like a viscous clutch. That does seem a bit crazy.

On our buses, they either have the hub mounted electrical clutch or an old school viscous clutch.

Sorry for my ignorant confusion....

No worries, I got happy for a sec looking at the picture you posted hoping there was another clutch off of a different Cummins engine application that would be backwards compatible before reading further.

For what ever reason Chrysler thought it was alright to put a harness in front of a deep pitch diesel engine fan clutch only to have it secured between two pieces of plastic mounted behind the radiator. It works until it doesn't, but constantly heat cycled plastics on a 20 year old vehicle are bound to fail eventually.

 

[Ozymandias]

It isn't Chrysler only, many modern Semis have that setup.
This is a proven design and works well with very little problems.

(mine cut the wire once, i don't blame it but have put a big ziptie at the bottom end of the wire to hold it more secure to tue shroud)

 

[CharlesinGA]

The '03-'04 shrouds are quite different from the '05 and up. The shroud mounts on the radiator, and the overflow bottle forms part of the shrouds outer ring that contains the air. the lower part of it fits very close to the radiator and effectively blocks about a third of the radiator from air flowing thru. There is a channel molded into this at the bottom toward the vehicles right side, and the fan wire harness has a matching molded section with a ring molded around it. You press this molded section into the channel in the shroud and then install the lower section, which locks it in place.

Its this molded channel in the bottom of the main shroud that rubbed a hole in a cooling tube of my original radiator. New GPD radiator is thinner, so the shroud does not touch the core. (new GPD radiator is a single row of 1¼ inch thick flues, while the original radiator is two rows of tubes with about 3/16 gap between them and the core is 1½ inch thick.)

There is a lot of room between the engine and shroud on the '03-'04 and its easy to replace the water pump or tensioner. Later models with the engine mounted shroud have much less room and its a lot more work. I did the water pump and tensioner on my neighbor's '06 because it had shredded the belt for reasons unknown, and he wanted the stuff changed but had just had surgery and could not do it.

The crank pulley was full of rubber from the belt, and I had to clean every groove all the way around with a pick.

The wires on the fan are contained in a plastic U channel and unless this gets detached or breaks the wires, on an '03-'04 will not contact the fan, if all of the pieces are there.

Charles

 

[User113]

For what ever reason Chrysler thought it was alright to put a harness in front of a deep pitch diesel engine fan clutch only to have it secured between two pieces of plastic mounted behind the radiator.

I wonder if it wasn't a "Daimler" idea and not a "Chrysler" idea? Lots of other crazy Mercedes notions seem to have slipped into Chrysler products under their ownership...

 

[Darkbloodmon]

I wonder if it wasn't a "Daimler" idea and not a "Chrysler" idea? Lots of other crazy Mercedes notions seem to have slipped into Chrysler products under their ownership...

Could be, Alot of companies were sharing the same crack pipe back then even more so now.

 

[Topzide]

I agree on the influence from Daimler. I had an '07 Caliber, you could see what looked like a European car under the hood! Sometimes the engineers need to take a break and get some fresh air! What happened to the days of trails that lasted months on roads and not in simulators. Some of the ideas have proven useful, others should have been pulled and thrown in the scrap bin!

 

[Tuesdak]

I wonder if it wasn't a "Daimler" idea and not a "Chrysler" idea? Lots of other crazy Mercedes notions seem to have slipped into Chrysler products under their ownership...

Same setup as GM’s (same era) Trailblazer with wires in front of the fan. At least they are now behind the fan like in my 2018 RAM.