DT-360 How hot is too hot?

[cadillackid]

on saturday we had our first real taste of summer.. it was 96 outside.. blazing sun dewpoint upper 60s..

im crusing down the road at 65 in the bus.. A/C blasting and saw my dash temperature hit 210 and creep just a hair above...

it never went any higher.. though I didnt hear my engine fan likeI thoght I should.. so I need to check of viscous thermal clutch...

anyway how hot is too hot for a wet sleeve engine like a DT360 or DT466?

is 210 too hot? what happens if it ran to 230? does it blow up?

I know diesels are much more sensitive than gas engines,(I once ran a gas engine up to 300 and it didnt blow up[the cooling system did but not the engine])..
I just dont know the actual limits and my service manual says nothing about what is considered Ok and whats not..

-Christopher

[EastCoastCB]

I haven't had a 360, but my 466 runs at 160 no matter how I use it. Only time I've seen it go up any was climbing up Monteagle in TN.

[cadillackid]

Originally Posted by EastCoastCB

I haven't had a 360, but my 466 runs at 160 no matter how I use it. Only time I've seen it go up any was climbing up Monteagle in TN.

I feel like my fan doesnt engage enough... ive always had issue over the years with viscous thermal clutches waiting way too long to engage..

I have a 180 Thermostat (us up here in the north need 180s).. so I exoect it to run 180-190 all the time.. I also wouldve expected to hear the roar of the fan at 210 and I didnt.. it was spinning when I stopped and opened the hood but id expect it to be running full speed (like when you first start the engine)...

thus far I havent found any good info on retro-fittng an air clutch into it..

does your DT466 have an Air clutch?

-Christopher

[Booyah45828]

Your likely fine. The whole how hot is too hot is always a tough one to answer. As long as it doesn't go uncontrolled and boil over I'd say your fine. The big problem is when it boils over, because then you have temp spikes and who knows how hot it gets in localized areas. As far as gaskets, liner O-rings, and the like leaking. That's anybody's guess. Could happen at 250, 210, 180, or when it's cold.

If it was mine, I wouldn't start to worry until about 230 or so.

A big question for you is when you stopped. Could you move the fan by hand? If you could, then you need a new clutch for sure. But going down the road at 55 you'd be surprised at how much air is flowing through the radiator. It's a lot more then what the fan could pull.

[cadillackid]

with a viscous clutch you can always turn by hand some... however when i idled down I wasnt getting the fan speed I feel i should be.. then again IHC might be like GMC was with their cars where the viscous clutch didnt really get going till close to 200 degrees radiator AIR temp.. which would be 205+ coolant temp..

its interesting at how my service manual doesnt even mention a viscous clutch.. I have air controlled shutters.. which are in manual disable mode for summer so they never close..

even with the air-clutches the service manuals dont talk about the actual temperatures in which they should engage, to give me an idea of where it should run....

I agree at speed the ram-air definitely is large... however the one thing a fan can do is reduce the ram air back-pressure and also reduce engine cxompartment temperatures which helps the engine run cooler..

I was definitely pushing my bus pretty hard ...at 65 my foot is to the floor 85% of the time.. however my aspiration for warm weather and hate of cold weather means that my bus will probably see more hot tremperatures than it will cold.. except for when im driving it to or from home in the winter or running it around home.. (ie taking my friends out, etc)...

since my service books make no mention of a viscous clutch it makes me wonder if the bus had an air clutch that went bad and was replaced.. or perhaps it was such a rare occurance or perhaps special order so it wasnt included in the service info...

I do find viscous clutches used on some other IHC trucks and even with DT-466 engines...

alot of parts from a DT466 and DT360 are interchangeable..

on my old cars....i used to be able to adjust the engagement temperature of these clutches.. and as a test I could disengage the thermal band and rotate it counter-clockwise .. if the fan went full speed i knew the clutch was good but out of adjustment... I think I'll see if I can do that to this one...

I also will get a tenperature probe and measure the AIR temperature coming from the radiator.. if the Air temp isnt that hot it means im dealing with an internal coolant flow issue.. if the air temperature is hot then time to work harder at the fan...

or maybe it all works perfectly and im just driving the bus too hard... then its easy.. I just let off and slow down... I do feel though like my fan shoiuld spin faster when stopped, revving the engine and it just stayed at one mediocre (but still air moving) speed..

-Christopher

[2kool4skool]

FWIW my 5.9 fan comes ON at 202f and OFF at 197f coolant temp. There's no doubt when it engages. The fan does not move when running unless it's hot enough to engage.

I have a ScangageD.

[cadillackid]

Originally Posted by 2kool4skool

FWIW my 5.9 fan comes ON at 202f and OFF at 197f coolant temp. There's no doubt when it engages. The fan does not move when running unless it's hot enough to engage.

I have a ScangageD.

im all mechanical so I cant use my scangauge II in the bus..

im assuming yours is an air-clutch?

-Christopher

[cadillackid]

so I put a new Borg warner Fan Hub on today and now I actually have a fan that spins!..

I talked to Borg warner tech support and they gave me the skinny on how to adjust the temperature on the fan clutches... the Borg warner Viscous fan clutches are factory pre-set at 190-195 coolant temp which translates to about 170 - 175 air temperature at the radiator...

alas on MOST of the DT360 / DT466 S3800's half of the grill opening is the radiator, the other half is the turbo after-cooler...

this throws a standard fan clutch for a loop because the air from the turbo cooler and radiator mix.. the turbo cooler air is much cooler than the radiator air.. so the fan clutch may never engage properly.. (an air clutch works off of coolant temp not radiator air temp so it can be engaged whenever you want or with a switch..).

many older busses will have the viscous style fan clutches and will cool fine until you attempt to pull a hill or work the engine hard...

Tech support at borg warner, and I came up with the idea to adjust the temperature down.. the thermal "spring coil" on the front of the clutch as "tick marks" on it... the green line is the factory setting... each tick mark is 10 degrees f.. you loosen the 2 star bolts and then move the slider with the "center line" to the LEFT for cooler engagement and to the RIGHT for HOTTER engagement.. I moved mine 2 tick marks to the LEFT and presumable that shoul;d engage the fan at 150-155 degrees AIR temperature from the radiator...

the results thus far on an 84 degree day are my bus gets up to about 182 and I hear the fan engage at a higher speed and then the bus temp goes back to 180 and the fan slows down... it is progressive unlike an air clutch..

also a viscous clutch has a minimum speed that cannot be set.. the particular one I bought has a minimum fan speed of 450 RPM ewhich keeps the engine cool under many circumstances without full engagement of the clutch... my old clutch had a minimum around 300 RPM or so.. (or may have been 450 originally but since it was broken it was slow)..





-Christopher

[2kool4skool]

Originally Posted by cadillackid

im all mechanical so I cant use my scangauge II in the bus..

im assuming yours is an air-clutch?

-Christopher

Electronic fan control.

Scan 2 wouldn't work anyhow, need the D.

[cadillackid]

Originally Posted by 2kool4skool

Electronic fan control.

Scan 2 wouldn't work anyhow, need the D.

Borg warner makes a kit to upgrade mine to electronic fan if I wanted to... I learned this after I already had my viscous clutch in hand so i went ahead and installed it.. and it works thus far so I'll keep it...

it appears the other clutch was the incorrect one for the setup... it likely worked for a long time as a fixed-speed fan.. it was designed to run the fan at a % speed of spindle.. as they wear and go bad they become unable to maintain the higher speeds...

since my bus lived in ohio and the school system it was used in has no summer programs with busses it likely was never noticed as bad.. till I got it and started runningit on the freeway in hot weather...

-Christopher

[cadillackid]

The new fan clutch fixed the issue... tyoday was little over 80 outside and I was running up a hill... temp got to about 182 on the dash and I heard the fan engage in and out to keep the engine temp 180-182 which is right where I want it to be... I have a 180 thermostat so that is keeping it right there... next week we see 90s but im confident it will stay cool...

I also had a lot less heat in the driver compartment since I was keeping the engine cooler.. it is now blowing alot of that heat away..

-Christopher

[2kool4skool]

Good! I mean Cool!