| Author |
Message |
joe shelton (64.222.182.123)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 10:09 am: | |
My engine has been over heating on climbs and low speed (less than 60 mpr). I was going to remove the control oil lines from the fan drive and plug the ports on the engine and fan unit so that the fan would be blowing max air all the time. But my mechanic said it would be a big power drain and I should find why I'm having over-heating & fix that. Also the fan drive seal is leaking but I doubt that has anything to do with it. What do you all think? Joe 4106 |
Jim-Bob (12.46.52.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 10:44 am: | |
I agree with your mechanic. The bus was well designed & ran literally millions of miles with that fan drive. The drive was also designed to save fuel, horsepower, noise, and to let the engine warm up faster. If the bus is overheating, there IS a valid reason. Now, it COULD be the fan drive thermostatic valve. You can test that. Could be a clogged radiator or other issue.
Since as I understand it, the thermostatic valve controls the oil returning to the engine, thus the level (percentage of slip) in the fan drive, why don't you install a ball valve in the hose going to the thermostatic valve to see what happens if you close it, simulating the valve closing. You could also bypass (replace) the thermostatic valve with the ball valve for test purposes. That would be a pretty cheap test device. If the therm. valve is not the problem, you haven't buggered up the system.
The old GM engineers really did know their stuff. |
darisb (209.67.181.129)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 10:47 am: | |
Did you check your thermostats? Another thing you might want to check is your fuel pressure. My 4106 ran hot when I first got it. Especially on grades, but also in the desert.
My fuel pump went out. It hasn't over heated since the fuel pump was replaced. I took it on a 4,500 mile trip, shortly after replacing the fuel pump. I climbed the Rockies and the Grapevine in August. I tried to keep it around 1,700 RPMs on the grade, and it never over heated.
Regards,
Daris |
jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 11:12 am: | |
i agree with jim-bob... check your radiator for flow... you can use a infrared thermometer and find hot/cold spots in it... you might also check the water pump impeller.. to see if its slipping...thermostats are cheap and easy to change... |
John Bessette (170.215.80.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 2:29 pm: | |
Joe
I went to the direct fan do to my fluid drive was leaking bad and the guy at Deans coach said that was the way to go because they all leak. that gm did away with them in later models but that may not be the reason yours is heating up.
John
4106 |
joe shelton (64.223.180.226)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 3:28 pm: | |
good stuff. thanks. I'll start with thermostats and go from there. I have an infrared thermometer; so if I find a cold area on the radiator, what does that tell me? |
jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 3:42 pm: | |
measure the temps on the water lines AFTER the thermostats.. then measure the water temp BEFORE it goes into the water pump... temp differential should be 12-15 degrees... more than that means the water is moving too fast thru the radiator (like thermostats stuck open)... less than that means it's moving too slow.. (like radiator stopped up)... make sure that you measure the temp on the same material (both steel lines), instead of 1 being rubber, the other steel... you can put a piece of black electricians tape on the piping, it helps to standardize measuring...if you can acess the radiator directly, you can find the path of coolant....btw, have you checked the radiator cap for holding the right pressure??? |
Frank allen (64.12.116.135)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 4:59 pm: | |
my fan runs all the time on y 06, this was done when i added in dash a/c, needed the air flow over the condenser which is over the radiator, but the bus should not heat up assuming you are running the standard spicer you should be able to climb all day in the 100 deg temp at 180 degrees, i climbed the mountains on both sides of the country towing a car and never got over 180, probly need the radiator cleaned out or rodded. will run hotter with a 730 transmission depending on how they are cooling the oil, hope all this helps
Frank Allen TX 4106 |
Luke Bonagura (Lukeatuscoach) (209.247.222.102)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 10, 2004 - 7:21 pm: | |
Joe:
When I talked to you yesterday, you indicated that you thought your fan may not be running at full speed. That is why I suggested that you bypass the vernitherm valve and take the coach for a ride.
When I was operating 4905's and GM Fishbowl Suburbans in commercial service, they all had the vernitherm valve bypassed. The coaches operated on regular route service with a combination of Highway (here in N.J.), and local stop & go traffic in the city of Philadelphia, and we never had an overheating problem.. There was never a horsepower problem, because when the valve is hooked up and operating properly, then fan goes to full speed as the engine. temp. approaches its' normal 180 degreee operating temp. and stays running. Only drawback was in the winter, as it would take a bit longer for the interior coach heat temp. to be comfortable.
You have already received other good info. above on troubleshooting your problem and in answer to your additional question about cold spots on your radiator, if you find that to be the case, I would suggest the follwing:
Pull the radiator, send it out to a commercial radiator shop who will disassemble it, cook the core, rod it out, reassemble it for you, and it should be "Like NEW" if the core is in good shape.
I Hope this HELPS!!! and you have the phone number if I can be of further asistance.
LUKE at US COACH |
Bob Gallo (66.142.237.63)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 11, 2004 - 1:14 pm: | |
I've had recent problems with the Torus fan drive. I changed to a 6V92 (350hp) and kept the fan drive from the 8V71 for a better physical fit. Plus I liked the idea of the efficiency. Here is what I did wrong.
1. I used the 6V92 RTS fan. It was bigger (32"vs30"), and I thought better because of it. It turns out the drive can't turn that bigger fan. It slips and gets hot (VERY HOT). It also self destructs more than normal.
2. I rebuilt the fan drive. Though not normally a bad thing, it turns out information and parts are skimpy. If disassmbled, be very careful about what goes where as the books don't tell you. We eventually found (after taking the thing apart about 8 times) that one of the seals was not in the correct position causing loss of oil from the torus, causing slippage. We had to add a shim between the drive torus hub/seal and the adjacent bearing. This set the seal in a better position and moved the two turbines closer together. The books don't show this shim. Was it there originally? I don't know. Were the bearings that I used to rebuild different in some way causing the dimensional difference? They were the original part numbers, but maybe were subbed by the supplier.
As a test, I would block the drain line (the line to the thermo valve) and use an optical tach to see that it comes within a 100-200 rpm of crankshaft at full throttle. If not, you have fan drive trouble.
By the way, I have dash air and use a solenoid to block the return line, making the fan run full on when the AC is on. Otherwise, it works normal.
On my recent exploits, I started out with temps up to 220 on a "test run". After the mods, it lowered to 190 max.
I have had the unit not leak. It's pretty easy to get most of it sealed, the only part I have trouble with is the fan shaft seal. Sometimes a brand new seal will leak. Change it and then its OK. I did remove the aux drive part of it. I blocked the oil passage and made a cover plate.
At one point, I had trouble with the output(fan) shaft seal blowing out. This causes a major loss of engine oil in a hurry. It is a close to a catastophic event as punching a hole in the oil pan. I think the bearing was in the initial throes of disintegration with pieces of the retainer wedging the seal out. The bearing failed later and the problem was obvious. Because of this, I think an oil level sensor would be good as by the time you see the "oil" light go on at 70mph, the motor would be toast. |
Jim McArthur (216.239.172.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 12, 2004 - 2:11 am: | |
On my 4106 I was overheating and noticed the fan drive was leaking oil and also the fan blades were a little wobbly. We also found the bearings were in bad shape. Fixed it and headed south and still overheated. The fan wasn't turning fast enough so we plugged the lines to the fan stat and went direct.
this got us through the trip although not much heat inside. Got back and decided to look at the Fan Stat. There it was. Parts of bearings was in the stat which wouldn't allow it to open or close. We replaced the fan stat, hooked the lines back up and its now running like it should.I replaced the other two thermostates but they appeared ok. Hope this helps. |
FAST FRED (4.245.221.180)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 12, 2004 - 5:23 am: | |
A fan rigged to be ON all the time will cost about 2 or 2 1/2 gal per hour extra fuel consumption (30 to 40HP), just to spin it.
Fixing the rig back to stock makes the most sense with todays fuel costs.
FAST FRED |
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