The tech at the shop mentioned to me that the shutters on my 4108 are not moving like they should. They apparently are pretty much always at about 45 degrees - sort of half open. He says that they should be more closed on a cold engine and more open on a fully warmed engine.
When operating on the freeway with temps in the mid-70s, the engine temp never got more than 180.
The tech suggested that I remove the cover and start dripping oil on the pivot points to free them up. There was nothing in the manual about this other than a brief paragraph, and no pictures.
Before taking anything apart I thought it might be a good idea to ask if anyone else has had experience with the shutters and could offer suggestions.
Thanks!
At least with MCIs, you only need them if you are going to idle overnight at 20 below. I would remove them.
JC
Probably sticking pivot points or seized shutter cylinder that operates them.. There is a reservoir to add shutterstat fluid to btw. There should also be a petcock to shut off the air to allow them to stay open. We kept them working on the 4104 as it would run cold on light load on the level or down long grades. We don't have shutters on our 4905 as it has the hydraulic fan.
Probably sticking pivot points or seized shutter cylinder that operates them.. There is a reservoir to add shutterstat fluid to btw. There should also be a petcock to shut off the air to allow them to stay open. We kept them working on the 4104 as it would run cold on light load on the level or down long grades. We don't have shutters on our 4905 as it has the hydraulic fan.
We removed the shutters on our 4104. They were pretty worn. If we ever needed to slow the air down, we'd just use a zippered jacket like the truckers do. Removing it helped keep it cooler when it would normally run warmer. Besides the thermostat take care of the rest.
oil and operate. repeat.
ok oil once and manually operate 78 times, then repeat.
if they are salvageable.
if not i would simply open and leave them
but i like my stuff to be as original as possible.
shutters are good.
Wisconsin can be cold.
Either working Torus on the hydraulic fan, or shutters, you will want one or the other for cold weather operation.
I kept the shutters functional, and neutered the damper doors in an MC8.
For the time being, find the air shut off valve, and get them all the way open. They either close all the way, or open all the way, they do not graduate.
happy coaching!
buswarrior
I dripped oil in the pivot points for a while and was able to get the shutters to move, but only with a lot of effort. It seems like the air cylinder is used to close them, and there are a couple of springs that are used to pull them open again when the temps raise.
They close easier than they open, especially since the air cylinder is helping that take place. I'm slightly concerned that if they close on their own now they won't spring open when necessary.
Anyone have any experience taking one of the shutter assemblies apart for a proper cleaning and reconditioning? Doesn't seem like it should be all that difficult, but I'm hesitant to just start taking things apart unless I have some idea of what to expect. Unfortunately, this is not covered in the manual.
the odds of rejuvenating them in one piece, whether in place or on the bench, are better than a total disassembly..in my experience.
on mine I lubed all the moving parts and worked them back and forth with the air cylinder unhooked . it didn't take to long to get them working like new but I had to replace 1 air cylinder and all was good .
many a time it was cold 0 to -10 f when we left home to go south and it makes a huge difference for heat
dave
Disconnect and remove shutter assy. Get it on bench and liberally spray pivot points. Let soak overnight. Repeat. Once the penetrant does it's job things will loosen nicely. Don't rush and try to force them to move too soon. You'll twist paddles and they won't close completely any more. Do not dissemble assembly, but remove springs before applying penetrant. Take cylinder apart, clean and lube. I remember they use leather or felt covered piston which is kept !ubed by a reservoir, that also has an on off valve. I believe they are Kysor shutters and use Kysor shutterstat fluid for the lubricant.PB blaster penetrant works well for this and is available at Wal Mart.
My manual X7564 shows the shutters, air cylinder, and temp control switch with limited info on service. This information was much more detailed in the 4104 manual when shutters were on all or them. Optional on 4108 and 4905's.
Think hard about replacing the springs, and confirming that they are actually in place to start with.
Find the air pressure shut off valve, both for now and future use.
My pictures reside on a drive that isn't accessible at the moment. Who has a picture?
Air turned off, shutters should stay open with the springs.
happy coaching!
buswarrior
I finally got around to working in the shutters. After only about half an hour of working on them, I was able to get the shutters freed up and moving quite freely. With the air line disconnected I can manually close them and when I let go the springs snap them open. This is a good thing.
I reconnected the air line and started the bus. At full pressure (but still cold engine) the shutters were staying open.
A quick phone call to Luke and I learned that they're probably set for summer use so that they stay open. There is an air regulator above the engine with two T-handles to control air flow. Luke says that in summer one is closed and the other open, keeping the shutters open. In the colder weather I simply reverse the two handles and this allows air to flow to the shutterstat.
There is nothing in my manual about the shutters that I can find. Anyone have any additional information about the shutter system which was an option on the 4108? Main thing I'd like to know is which T-handle is supposed to be open/closed during each season so I'm not guessing. If there is a manual page about these it would be great to see what they said.
Thanks.
in the "winter" position..the shutterstat will tell them to open when they reach the "it's to hot setting...i need to cool.
i never heard of a ...summer keep me open setting.
they are spring open
air closed
should do the same thing in January as it would in June.
Just going by what Luke told me earlier. There are two T-handles on the air regulator. My guess is that right now the air is shut off to the shutterstat.
Shutters are very important. And they have to be free operationals. They permit the engine to get to his operational temperature more quickely. The only concern is to watch them if they open beafore the fan kik in. If the fan start and the shutters are closed,the shutters will not open beacause of the suction from the ventilator. Overheating will soon beacome. The shutters should open first,then the fan can start working full blast.
Quote from: Templar52 on May 11, 2018, 06:28:38 PM
Shutters are very important. And they have to be free operationals. They permit the engine to get to his operational temperature more quickely. The only concern is to watch them if they open beafore the fan kik in. If the fan start and the shutters are closed,the shutters will not open beacause of the suction from the ventilator. Overheating will soon beacome. The shutters should open first,then the fan can start working full blast.
I'm guessing that this doesn't apply to my bus then, as my radiator fan is not on a clutch and spins all the time. The fan on the 4108 is not set up like it is on the 4106. That's the reason there are shutters from what I understand.
No and no.
Shutters that are freely moving and springs in place, they will not be kept sucked closed by the fan.
Notice their clever shapes, and the geometry of their movement and linkage, there is aerodynamic and engineered design involved here, those aren't just slabs of metal hanging in there...
MCI fan sucks full speed, full time against them. Just fine.
Happy coaching!
Buswarrior
Buswarrior - Have you seen the shutters mentioned in a GM manual at any point? I can't find them in my manual and would love to see what the manual entry looks like, if there is one.
My manual has a little about the shutter system. The air cylinder and shutterstat itself are non serviceable. The shutter stat is mounted in coolant passage of engine. One lines connects to shutter control air cylinder. The other line goes to shutter air control unit on firewall. It receives it's air supply that also supplies the engine control solenoids. The shutter air control unit filters air and injects small amount of shutter fluid to shutter air cylinder along with the air. There is also a shut off valve that will allow shutters to stay open when desired for servicing or in hot weather if desired. There is a cap you remove to add specific shutterstat fluid to reservoir periodically. It is absorbed into felt packing in reservoir which allows a light mist of fluid along with air to the shutter cylinder. Their is a fuller explanation in the GMC 4104 shop manual when they were standard equipment. On the later GM's shutters were optional. My 1975 parts bus has shutter system with mechanical fan. Someone removed shutters, but left rest of system. They are useful for maintaining engine temp on light engine loading on level or slight down grades, especially in cooler temps. The 04 had an adjustable shutterstat. Newer ones were fixed at 175 degrees, I believe.
Shutterstat fluid?
Any ideas where one can get such a thing or if there is an alternative which is currently available?
Here's a catalog entry that looks like the control on the bulkhead above the engine. If my understanding is correct, the T-handle on the face is the on/off valve for the air flow. The T-handle on the bottom is the drain petcock. Maybe what Luke was saying is that for summer use the air is closed and the drain is opened, and that for cold-weather use the air is opened and the drain is closed.
The brass nut on the top of the left-side part looks to me where I'd add the shutterstat fluid. Correct?
Maybe someone with a 4104 manual (or any manual showing the shutter system) can verify this?
The parts all look to be in clean and relatively good condition. I'd like to see if they work, but before I start just turning knobs and adding fluid I'm hoping that someone can confirm.
When we ran the bus this past winter, it seemed to take forever to get the engine up to temp. Now that I've got the shutters themselves freed up, I'm hoping that the shutters system functions and will help.
Found a 4104 manual on another bus site. Was able to answer my questions about the hardware. Copy of manual pages attached for anyone wanting to take a look.
Only question left is where to find either Shutterstat fluid or a suitable replacement. Thoughts?
Since it is air controlled, the bottom petcock is to occasionally drain any accumulated moisture. Our 04 spent off road time in the shop when not in use. You could hear and see shutters open when air in system dropped off after a couple of days. When they are closed and engine is running, shutting off the valve, they would come open after a few seconds