Big Radiator Fan "HUB"

[Ray Davis]

That's kind of the temps I was expecting. I'm not seeing the cycling as you described. In fact, temps would rise when driving slow, indicating to me there may be a problem. I'm gonna have to check this out before any more trips.

[Jon Wehrenberg]

Mine will run anywhere from 195 to about 210 depending on OAT and if I am running on level ground or pulling the hills, or descending a hill. That is based solely on my interpretation of a little round gauge whose accuracy I have never questioned or checked.

[JIM CHALOUPKA]

Finally got the old clutch unit out PITA. Very heavy aro 40# and must be lifted by outstreached arms with the casting passing through a space in two places simultaneously that only have .030 in clearance.

More to follow.

JIM

[JIM CHALOUPKA]

Prevost calls out AX74 to be the correct belt to go from the engine to the fan gear box.

My bus has AX73. Does anyone else use AX73 and why.

I have had no ill effects with the AX73 and am reluctant to change, but I also would like my bus to be up to Prevost specifications.

Opinions and discussion please!

JIM

[lonesome george]

Jim,
Mine has AX74 belts. I don't think the shorter belt can hurt anything, it is only about a 1/2" difference in center distance. I have had the entire pivot plate for the right angle gearbox and fan clutch out of our coach, where the bottom half of the pivot mounts to the chassis there are some large slots for adjustment of the whole thing. If you want to use the AX74 belt you may need to make an adjustment at that slot. What I made sure of is that the when the mount moves thru it's range of travel with the belts off the fan did not hit the shroud when the air bag was compressed and it did not hit the radiator before the mount stacked up on the hard stop on the air bag mounting bracket.

[phorner]

Jim, while your're in the radiator area, you may want to check the condition of the radiator core.

While at parliament coach recently having my OTR serviced, I also wanted to thoroughly go over the engine cooling system. I wasn't having any high temp issues, but since we're headed out to Arizona and Nevada at the end of July, I wanted to be pro-active.

So, we drained the coolant and pulled off the lower radiator hose to take a peek at the core. Not bad, but there was a build up of deposits that looked nasty, although none of the passages appeared plugged. I'll bet this hasn't ever been inspected on my coach.

After a thorough cleaning and several flush cycles, the difference was quite obvious.

Fresh coolant and a new coolant filter followed the cleaning. I do believe this process has dropped the running temperature a few degrees, as we never exceeded 199 on a 3 hour trip in 90 degree ambient air temperature. And, the temperature would drop down to about 193 after the fan kicked in.

Not the cleanest job to undertake as it's a challenge to capture all the coolant as well as the cleaning treatment gunk.

But I like the feeling of knowing that I've done about all I reasonably can to assure a trip without an overheating episode.

[JIM CHALOUPKA]

Good suggestion Paul. I will wait with that for now. Putting it off until I change the EC 1 coolant. I think that's the right designation.

A note on the fan clutch. I am confident in stating that my clutch has been changed before at least one time, so anyone with 115,000 ish miles would do well to keep an eye on things.

JIM

[Pete]

Jim, mine has the AX73's. When I had my fan clutch/radiator problem, prevost tried to put the AX74's on and could not get the clutch/a/c platform adjusted far enough away from the radiator to avoid possible contact. Thus the AX74's were installed.

[dreamchasers]

Jim, mine has the AX73's. When I had my fan clutch/radiator problem, prevost tried to put the AX74's on and could not get the clutch/a/c platform adjusted far enough away from the radiator to avoid possible contact. Thus the AX74's were installed.

Pete,

I have heard you mention concerning losing the three belts that drive the gearbox and the result was your radiator fan extended damaging your radiator. Sounds painful.

I checked my bracket and a piece of the metal bracket holding the small air bag that controls the belt tension will prevent this over extension of the fan. If you unit does not have this bracket design, perhaps an upgraded bracket would prevent future mishaps.

Hector

[Pete]

I'm sorry, thus the AX73's were installed. Sorry bout that