Advice on 454 radiator cooling fan

[porourke]

Our 93 LY has started making a little racket when the engine warms up enough for the radiator cooling fan to come on. I have been hesatant to use it. It may be getting close to time to replace it. I have taken it up on the freeway and in stop and go traffic on the side feeder and it doesnt over heat. On two occasions it has come on with a cold engine as soon as I cranked it up. If any one can give me some advice as to how to get to it and change it out we would appreciate it. We are retired and I will have to try it first. Its on a Chevy P30 Chasie.

[easyride]

You probably have a fan clutch going out,I would replace with a flex fan. Dave

[John H.]

some place ? there is a very good thread on changing the fan, and water pump out and a , How to , and parts options, recommendations.

If you can search and find that thread you will get much Help. this is IT maybe

http://www.airforums.com/forums/f159...ned-54659.html

[slowmover]

I wouldn't substitute a flex fan for a thermostatically-controlled fan on any big block gasser expected to do work. I would be careful about the brand and exact specs of the clutch as well as finding a replacement fan (if the old one is worn, chipped and/or out of balance). I'd also carefully examine the fan shrouding to be sure the fan/shroud interface is ideal for efficiency (fan blade tip placement). That gap is sometimes too big, or off-center, etc.

[porourke]

Well things have gone from not to bad to very bad! Took the coach down and brought enough gas to get it up to half a tank so we could use the generator and just as I got it back in our slot in the storage facility the water pump froze up just as I was about to kill the engine. At first I didnt know what it was. Took the engine cover off and got the air breather hose and air filter taken off. Took the wooden tray off the top of the dog house cover and tried putting it back in place but not all the way up to the TV to lay on and managed to get the first two belts loose and everything but the water pump pully will turn by hand. There is also an other problem, the fan clutch has some side to side play in it, that will have to be taken care of also. I took some measurements to make a plywood stand to lay on that will get me down lower, I think if I also take the AC compresser loose and get it out of the way I will be able to get both arms and hopefully my head in there. Any body have any advice or know of posts that give info that may be helpful. One thing I would really like to know is once I get the fan loose from the clutch will it come out the opening I am working through. Its a five bladed fan and I would like to replace it with a seven bladed one. Any advice or comments would be greatly appreciated.

Pat

[Robfike]

I have replaced the fan clutch a couple of times, and the water pump once. Really not that big of a deal, just a PITA! As far as getting the fan out, I'm sure it would come out but will be a bigger PITA. I have just left the fan in the shroud when doing the other work.
It's also a good idea to keep one spare belt for everything except the alternator. For it I keep 2. I also replace the alternator belt every other year.
Rob

[porourke]

Thanks for the input Rob. I am semi retired and was off the whole weekend 4 dayes and managed to get the water pump off after I serarated it from the fan and fan clutch. Brought it home and while I was handeling it I noticed that even though it was locked up solid when I moved it around it made a light ratteling noise. I threw it up on the workbench and took the 6 bolts that hold the back cover on and the hair on the back of my neck stood up. I had seen this in older cars before. Small bits of caroded and rusted steel, some of them long and wire like got caught inbetween the empellar and the pump housing. Went back to the MH and found the other end of the lower radiator hose that I had taken loose to get the pump off and put a empty 5 gallon paint container under it and took it loose. After it quit draining I got the hose out and the spring they put in lower radiator hoses to keep them from collapsing during heavy acceleration had deteriated to the point to were it came out in three pieces with an ungodly amount of small stuff. No use in putting a new pump on till I get all this stuff cleaned out of the system or the same thing will happen to it.

I got the old pump freed up and am seriously thinking about putting it back on and taking the thermostat out and rigging up some kind of inline filter, we have several at the plant used to separate shavings from coolant. Once its clear put a new pump and a new thermostat on. Any one been through this before appreciate some in put.

Pat

[Robfike]

Wow, that's one I have never seen. I wonder how old the hoses are? I replace all hoses every 4 years. After spending 25 years in aviation, I like to replace things before they become problems!
I just replaced all of mine back in July. The two everyone forgets are the little heater type hose between the water pump and the intake manifold, and the filler extension on the front of the radiator.
Good luck, Rob

[dznf0g]

Folks, I am wondering why no one has tried removing the clutch and fan, and replace with a pair of electric, thermostatically and A/C clutch controlled fans.

I hven't done any research on MOHOs specifically, but there are many applications for various big block street rods, race cars, muscle cars, 4 wheelers, etc. I know there are some load differences and cooling system diffrences, but it might be worth a few phone calls to the various aftermarket manufacturers.

Electric fans greatly reduce noise and help improve fuel economy (albeit, slightly).

[Phoenix]

Just my opinion, but if you have the water pump out, I'd replace it with a new or rebuilt one. Seems like it would be worth a few dollars to NOT be doing this again next summer (i.e., replacing the old water pump).

[porourke]

Phoenix - Reread my post. I only intend to use the old pump to flush the system out with no thermostat in it for best water flow. When the new pump, belts, and fan clutch get here I will put them in. One other thing. When I took the belt off that goes over the AC compressor and down to the power steering bump below it, I didnt notice that the power steering pump pulley has three belt groves in it! My chassis manual shows a single grove pulley. If any one has a three grove one like me, which grove does the belt go in, the one closest to the pump, the one in the middle, or the one farthest from the PS pump. Mine is not srepentine and no smog or air pump.

I found an inline coolant strainer with two different size screen mesh elements at the plant I can use. it has one inch female threads on both ends. If I can rig up an adapter to let me connect one end of it to outlet were the thermostat is to the end of the upper radiator hose. Hope it will catch most of the debree in the system.


Pat

[Keyair]

Pat,
Not looked at my 345, but I am pretty sure my 1987 454 powered suburban has multiple V belt groovs for the PS pump and 2 belts on it. I will try to go look today, but I think one is dedicated crank pulley to PS pump and the other goes crank pulley to PS pump then up to A/C Compressor.
So 2 different length belts!

Remember that the PS pump drives the Hydoboost and therefore the brakes, and has to work extra hard. If it should have 2 belts on it make sure it does!
I would take a straight edge and put it across the outermost pulley face and see what it lines up with.

[porourke]

Keyair - I thought that I may have had a belt burn in two and fall down below the block. Whent back and looked and thats not the case. The water pump pully has only 2 groves in it. The front one that drives the water pump and alternator off the drive pully is much wider than the back belt. I couldn't get a streight edge in to see which belt grove ligned up with the back groove in the water pump so I took some string and rapped it around all three pulleys three times, one time on each of the three grooves on the power steering pump pully and the streightst line, eyeballing down the string, it is the back grove on the PS pully seen to lighen up OK.

Pat

[porourke]

Finally found the third belt! It made it all the way out the bottom and was on the concrete slab just far enough back where I couldnt see it under the block. Found a correct drawing online and it goes directly to the crank pully.
Now it all makes sense. I took a snapshot before I took them off but didnt look at it. Later I went to look at it and it came out just about all white from the flash in such a small area.

Pat

[kmpro]

Hey guys
In replacing water pumps and fan clutches my experience has been better using NEW
OEM parts rather than rebuilt units. Be sure and replace the Bypass hose and if in doubt upper & lower radiator hoses too. Don't forget heater hoses and Aux heater hoses too. Replace coolant every 2 years and you won't have to replace as many water pumps. Last but not least don' t forget to replace the pressure cap with the correct PSI. My unit had a 12 psi cap on it when I got it, but the shop manual calls for a 16 PSI cap. After replacing it, my unit no longer has a tendency to overheat.
KMP

[Rollman]

The reason GM developed Dex Coolant is Green coolant PH changed after 1 year from a Negative to a Positive and in turn caused failures of everything in contact with the coolant, You can flush the system and install Dex but I have seen problems occur later with random failures. All I ever have been able to pin it to is the flush never removes residue from the green silicate based coolant and the Dex coolant. Dex is a great coolant for remaining a neutral acidic fluid but I would say stay with green if the coach came with, Just pour in a gallon of premix every year forcing out a gallon of old and you will eliminate the corrosion failures. Just food for thought Steve

[Journalist]

Originally Posted by dznf0g

Folks, I am wondering why no one has tried removing the clutch and fan, and replace with a pair of electric, thermostatically and A/C clutch controlled fans.

I hven't done any research on MOHOs specifically, but there are many applications for various big block street rods, race cars, muscle cars, 4 wheelers, etc. I know there are some load differences and cooling system diffrences, but it might be worth a few phone calls to the various aftermarket manufacturers.

Electric fans greatly reduce noise and help improve fuel economy (albeit, slightly).

Not sure with a 454, but I spent a lot of time researching that topic for my 6.5L diesel truck. The 6.5 already had cooling issues in the early models under heavy towing loads. When several people tried upgrading to electric fans, the problems worsened. Eventually, the belt driven plastic fan from the early Duramax turned out to be a far superior setup.

[dznf0g]

Originally Posted by Journalist

Not sure with a 454, but I spent a lot of time researching that topic for my 6.5L diesel truck. The 6.5 already had cooling issues in the early models under heavy towing loads. When several people tried upgrading to electric fans, the problems worsened. Eventually, the belt driven plastic fan from the early Duramax turned out to be a far superior setup.

Not the same animal at all. Those issues were unique to 6.5s. I have discussed with several co-workers and we're all scratching our heads as to why no one is considering this upgrade in MHs. A lot of options out there for big blocks. I'd start with Summit Racing.

[kmpro]

The OEM fan on 454s is the way to go. The fan clutch is thermostatically controlled by the sensor in the center of the fan clutch. If the sensor is not present, get the more expensive fan clutch with the sensor. In addition, I have my electric fans that formerly came on when the a/c was on wired to a switch so I can turn them on when pulling grades etc. Cooling a 454 is at best marginal in an AS Moho, but clean radiator and cooling system helps along with the aforementioned stuff. Don't forget to test your pressure cap on the system. My unit had a 12 psi cap on it when I got it, and the manual calls for a 16 psi cap. That alone makes a 12 degree difference in the boiling point. I also have a 50/50 mixture of prestone II and water in the system, I have heard that aftermarket parts offers a HO water pump, but I would have to check before recommending it.
KMP