Viscous fan clutch? DT466E 3800 dognose

johnbloem1974 · 01-03-2017, 09:56 AM

I was coming back from New Year's camping trip yesterday and noticed the coolant temp starting to climb higher than usual. (I have a scanguage connected so at least I'm getting an accurate number) I started to get a little worried as it got closer to 220 and I could not hear the fan engage like it normally does... I slowed down a bit, took back roads and was able to keep it below 220 and make it home.

Here's the question: are those things notorious for just going out? Is there anything I can adjust/fix on it or does it just need to be replaced.

Second question - is the replacement of it fairly easy?

Thanks in Advance!!

John

DoubleO7 · 01-03-2017, 10:08 AM

IIRC
when cold you can turn it by hand but "stiff".
Fan and the hub where blades are attached, not the part that the belt rides in.
Over time the shaft seal leaks and when the fluid leaks out it gets easy to turn fan by hand. Virtually no effort needed to move it.

I have same engine and chassis so I can look later tonight to see how difficult.

johnbloem1974 · 01-03-2017, 10:36 AM

just went out and checked - engine cold - fan turns pretty easily, doesn't have too much resistance on it. Also looks like there is some crud around the shaft like a small leak. I bet the clutch is shot.

Thanks!

John

cadillackid · 01-03-2017, 02:47 PM

viscous fan clutches... theres a few "issues" on internationals with them..

1. yes they can "just quit".. or they seem to take longer and longer to engage over time. so the engine creeps hotter..

2. they measure the AIR temperature from the radiator and NOT the coolant temperature.. so if you have any type of coolant flow issue or clogged radiator fins. the first thing that will happen is the fan wont run because the air temperature from the radiator is not high enough to engage it..

3. IHC SPlit radiator design doesnt help things... typically your turbo air is cooler than radiator air which keeps the fan clutch more towards disengage... esp when its cooler outside.. if your rad fins are clogged but your turbo fins are not.. even worse..

4. if your clutch has an exposed temperature coil (which many do) that coil cazn get covered / caked in dirt over the years. insulating it from the heat - raising engagement temperatures...

How I fixed mine.

1. I took the fan off and pulled the shroud back and cleaned my radiator fins.. (INSIDE OUT... the dirt is brought in from the front so blowit back out the front..).. I used high pressure shop air nozzle and then a garden hose and then shop air.. I didnt want to bend the fins or risk it with power washer....

2. I replaced the clutch with a part from kit-masters.. call your IHC dealer, give them the VIN, tell them you are looking for fan clutch.. they will give you a price.. ask the OEM part number, and then kit-masters can cross reference the IHC OEM part number..

3. what you will get is (hopefully) a thermal viscous clutch with an adjustable coil. (when you call kit-masters go through support and ask them what temperature its set at from their factory)... I reset the temperature down to 150 (2 notches from the factory 170).. on my DT-360.. now my fan engages fully when my coolant temp is close to that 185 point.. ive seen it go to 190 when it was a cooler day and I was pulling a hill... your mileage may vary with the DT-466..

4. I put the clutch on not by disassembling everything under the hood like the book says but by separating the fan from the clutch before unbolting the clutch.. on the DT-360 it was 4 bolts for the clutch to engine.., on the T-444E it uses a fan clutch wrench (I have the wrench set for those.. not sure what the 466 has)..

I slipped the clutch out, replaced it and put it back together without having to take anything else apart.. on my T-444E I had to remove the serp belt for a little clearance..

hope this helps

I have 2 happy cool-running busses after replacing those clutches on both..

-Christopher

BigDavid · 01-03-2017, 02:52 PM

The guy I got my bus from said he noticed it was running warmer than usual. He welded the fan solid & has never ran warm since.

Just a option.

johnbloem1974 · 01-03-2017, 03:51 PM

Thank you, Christopher!! I will give it a clean first and see what that does and keep you posted!

BigDavid - That's a thought too! Probably lose some precious MPG's though... ;)

John

Carytowncat · 01-03-2017, 06:28 PM

Quote:

Originally Posted by BigDavid

The guy I got my bus from said he noticed it was running warmer than usual. He welded the fan solid & has never ran warm since.

Just a option.

Thank you because as i was reading this i began to wonder why have a clutch at all?
I think i recall that engines perform better if brought up to temp, which would be tricky in winter but at least does not risk damage in summer.

Good to know an alternative exists.

BigDavid · 01-03-2017, 07:44 PM

As far as mpg goes, I calculated I got 11.89 coming back from Mississippi to Georgia. I need to put a few tanks in to really get a accurate number.

cadillackid · 01-03-2017, 09:03 PM

welding the fan clutch on a newer bus can be done however some implications.. on a big engine not likely to make a huge deal in fuel economy.. but the fan blades generally arent balanced for the full RPM of the engine... even when a fan clutch is fully engaged the blade is not spinning at the full RPM of the pulley.. so the bearing on whatever its attached is likely life-shortened..

your fan blade may also not be rated at the full engine RPM which means it could fly apart... that will usually destroy the radiator, the shroud, and often before you can shut down the engine it will bus the shafty or vibrate so hard it will shear the bolts..

secondly is even with a thermostat these biusses have a fair amount of coolant bleed to the radiator to keep the system from trapping air. so in cold weather your engine will have trouble making temperature esp if you idle at all..( alas why school busses have the pretty covers over the grill in winter.. ) or are like my DEV which has a fancy temperature cointrolled louver shutter that closes in winter.. (that I forgot to plug in the wire and so did me no good on my last trip to the great north)..

the belt - if your belt becomes even the slightest bit loose it will slip and break...

my suggestion? fix the clutch or buy a fan designed to be a straight run fan.. (yes you can buy fan blades that are designed to run at full engine speed for long periods of time..)
-Christopher

Tango · 01-03-2017, 09:42 PM

Dump the hydraulics and go electric.

cadillackid · 01-04-2017, 04:13 AM

When I checked for my 444e the retrofit kit was a grand or more and a new viscous was 220, adjusted properly they work great and you can easily get 100k plus miles.

The dt466 may be different as it was made much longer so it's possible there's cheaper options.
Christopher

PeteinSF · 04-17-2019, 04:32 PM

DT466E Kit-Masters = $387! Ouch.

cadillackid · 04-17-2019, 05:52 PM

shop around for it.. kit-masters is sold through various outlets.. they take the borg warner components and build the clutches.. mine were kit-masters buiolt but I bouight them, online for less.. all i did was get the kit-masters part number and shop it..

I ended up getting lucky and snagged the E-450 clutch from a guy who didnt know what he had.. for $250

_rideswell_ · 07-06-2019, 02:32 PM

On my DT466 the fan seems to engage at start-up when cold and shut off at 155* and does not turn back on.

On a warm day climbing a steep grade I can manage to keep the engine below 220* by running the heaters but obviously something is not right. Any ideas?

cadillackid · 07-06-2019, 03:07 PM

theres a few things...

1. the fan clutch measures the air temperature coming out of the radiator.. if the coolant passages are partially clogged then it results in higher engine temps, lower air temps.. so no fan engage.

2. the clutch can still spin up when it is cold and be bad.. its bi-metal temperature "sense" spring may be completely covered with dirt or is no longer functioning as it should..

3. some of these fan clutches are adjustable.. I bought a replacement for my DT-360 by kit-masters and turned it start speed down...

4. the startup-engagement is normal.. the fluid in the clutch settles overnight and it takes a few minutes for it to get spiun back into the correct places, thus the clutch will spin up at startup and for a couple minutes.. the clutch then returns to minimum speed.. which I know on my DT-360 is around 300-400 RPM fan speed...

-Christopher

_rideswell_ · 07-07-2019, 02:44 PM

Cadillackid,

Thank you for clarifying the start-up engagement. I could not figure that one out but now it makes complete sense.

I will try cleaning everything up and go from there.

Thanks again.

Quote:

Originally Posted by cadillackid

theres a few things...

1. the fan clutch measures the air temperature coming out of the radiator.. if the coolant passages are partially clogged then it results in higher engine temps, lower air temps.. so no fan engage.

2. the clutch can still spin up when it is cold and be bad.. its bi-metal temperature "sense" spring may be completely covered with dirt or is no longer functioning as it should..

3. some of these fan clutches are adjustable.. I bought a replacement for my DT-360 by kit-masters and turned it start speed down...

4. the startup-engagement is normal.. the fluid in the clutch settles overnight and it takes a few minutes for it to get spiun back into the correct places, thus the clutch will spin up at startup and for a couple minutes.. the clutch then returns to minimum speed.. which I know on my DT-360 is around 300-400 RPM fan speed...

-Christopher

Joe45 · 09-26-2019, 12:50 PM

My bus threw an overheat alarm at about 55mph in Phoenix, AZ back when I first drove it home. Scared the hell out me. I slowed down and temp dropped back to normal fast.

I'm about to pull the fan and clutch off of my t444e engine because the clutch is shot (fan spins easily). Tony at AAA Bus, where I bought the bus, is going to send me a new clutch (also a new alternator because mine is fluctuating volts).

Do I need a special wrench for the fan clutch removal?

Is it counter clockwise for removal?

Is there a better fan upgrade to help with temperatures?

I'm going to look into flushing the radiator etc.

Also thinking of routing the heater from the inside rear of the bus to somewhere underneath, to act as a second mini radiator. I've heard of people running the heaters to cool the engine, so I think its better outside than in.

Any other ideas?

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