-
Coolant Fan
I rep[laced my chipped fan with new on close to $300. Started up ran fine. This afternoon I started it and was having a problem with the engine starting. Happens when I fool with that switch in the back, which they say to turn on if you are working on the engine. Back to normal position and no start from the front, I go back flip the switch many time hoping it is a poor contact in the switch. No luck so I start the coach from the rear not a problem. The engine coughs and shakes start running, I see the fan cradle (8v92) jumping and I hear a snaping notice but the engine is running smooth. I stop for the night to flip the rear switch to off and I see one blade of my new fan with a chunk of it. Does this go back to the discussion earlier about airing up the fan bellows, in my case a pneumatic pistion.
Got two hundred miles on this trip and I have three issues, two with the bus.
God only knows what’s ahead for me.
Greg
-
12 Replies
-
Greg, because you have the pneumatic tensioners on your 8V92 (only OTR equipped coaches had them) there should be a limiter to prevent the fan from contacting anything because of lack of air in the system (belts loose) or due to a broken belt which would push the fan into the radiator.
If your blades are getting chipped I suspect something to limit travel and prevent fan blade damage is missing. Next rally you might want to check out OTR equipped 8V92 coaches to see how they are equipped.
-
Greg,
We have a 92 Liberty XL40 and the fan is about 2″ away from the face of the radiator when there is no air on the tension cylinder and it is collapsed all the way. When the air is applied the cylinder extends and actually pushes the fan closer to the radiator. The cylinder travel is such that if the belts break the fan can not contact the radiator.
As far as the circumference of the fan,,,, there is about an inch or so from the fan shroud. I do not see any way of the fan contacting the shroud or radiator unless there is an incorrect cylinder or the fan gearbox bearings are bad or mounting bolts are loose.
I have pics but unable to upload to this site for some reason.
-
If the engine starts up tough the fan and it’s cradle jump back and forth which casues the fan tips to hit the protector on the face of the radiator. I will have to look and see how to limit the travel. Very help suggestion.
-
If you limit the travel in that direction it seems to me your belt will be loose.
I question the belt length. Are you sure you have the correct belt ? It looks to me like my belt length keeps the fan from traveling far enough to hit the radiator protector. The cylinder must travel closer to the radiator if the belt was not there or too long. Otherwise it would not maintain tension if it were at the extent of travel. My belt is a 3 rib Gates Powerband A-92. I think that means 92″.
The cylinder travel should be short enough to keep the fan from hitting the radiator protector in case the belt breaks but the clevis mounts may be worn enough to allow the fan to hit if it is bounced, but again the belt would have to be longer to allow that. I have also read about a check valve to prevent bouncing. Not sure if our coaches have that.
-
There should be a mechanical stop in each direction on Greg’s fan mount. Originally there was not, or the stop was inadequate because a few early coaches with the heavy steel bladed fans had damaged radiators as a result of belt breakage.
-
I had the belt replace a few years back it, could be the wrong one. I do think mine is a Gates 93 so you may be right. I will get a new belt. I won a free Level III service from Prevost Mira Loma ($800) looka like this is going to cost me more just to go a get my prize.
-
Just keep in mind like Jon says, if the belt should break there should be a stop of some sort to prevent the fan from hitting the radiator protector,, if it is not the cylinder then a fixed stop. I have looked mine over really close and do not see any stop on the fan cradle, but maybe mine is the cylinder stroke. There is a check valve to prevent bouncing and maintain tension pressure, you may want to check or clean it while you have it down. It is located close to the tension release valve.
-
Robert
You nailed it I replaced my valve cover gasket and looked at the coolant belt. Gates a94 two inches too big. Called around today and could not find anyone selling a Gates A92 three ribber. One store called me back to say they Gates no longer makes them and you have to buy three single rib A92. Even Prevost in Mira Loma told me they couldn’t be sure they could get me one.
The air cylinder is the what is stops the fan cradle but when it is adjusted to tighten a tweon to big fan is doesn’t stop the cradle.
-
Glad to hear it.
I found this site for belts,,, I bought a spare last time.
http://www.vbeltsupply.com/ecommerce/a92-03-banded-classic-belt.html
-
Robert if I was not on the road I would have two of these in the mail.
Greg
-
Not sure how far away you are but I have a spare belt if you are in Florida. Will be in Ocala from tomorrow through Wed.
-
Thanks Robert but I am in AZ right now and got a new belt at Mira Loma for $50, will probably buy another off ebay or amazon later for a spare.
Log in to reply.