2nd Gen Non-Engine/Transmission Misc. Questions...

[TX-TowRig]

Just installed a gauge after LP failure and replacement:

12. 5 at idle

10~11 at cruise

7. 5~8 at WOT

Are these too low for a new pump?



Cruise Control took a dump on me. Checked for a bad vacumn hose under the battery, they all looked good. I will check the brake switch next. Is there any way to tell if the actuator is bad? What else could it be?



Need to flush radiator - I have heard of people adding some powdered detergent during the flush. The engine overheated a few times pulling over some passes and I had to add regular water - I have added at least two or three gallons of water in there (pretty diluted). I want to get it fixed up right, what is the best way?



Scott

 

[GWHaley]

Need to flush radiator - I have heard of people adding some powdered detergent during the flush. The engine overheated a few times pulling over some passes and I had to add regular water - I have added at least two or three gallons of water in there (pretty diluted). I want to get it fixed up right, what is the best way?



Scott [/B][/QUOTE]



This question is the only one I will address as I don't have any good advice for the others (maybe this one too). You should only flush the cooling system with water. Do not use any detergent! The only reason for using detergent would be an oil cooler or other type failure that contaminates the cooling system with oil. If that happens, you would use only powder DISHWASHER detergent. Absolutely nothing else! But it dosen't sound like you have that type of failure, so don't worry about that. Make sure your t-stat is working properly and that the outside of your radiator is clean.

 

[Extreme1]

Was your fan cycling on when the engine overheated? That would be my first suspicion...

 

[TX-TowRig]

Pretty sure the fan was working, just had alot of crud in the radiator. I have cleaned the outside of the radiator a couple times since it overheated (long 3rd gear pulls in AZ, NM, and CO)

It just needs to be flushed since it has never been changed - I have just added water when needed

 

[Extreme1]

Could you hear/feel it engage? My fan clutch died and the only sign it wasn't working was overheating while towing up hills. It had been dead since I bought the truck 4 years before, it was the first time it had been loaded enough to cause overrheating.

 

[Loren]

Scott,



1) I think those numbers for fuel pressure are fine. Undoubtedly you will hear other opinions.



2) I agree that your radiator is probably not your cooling problem. I also would suspect the fan clutch. When the fan clutch is working properly, and the fan engages, it come on with a roar. It is hard to overlook. The first time you hear the fan engage, you wonder what's wrong with your truck.



If you haven't heard this sound with coolant temperatures indicating well above normal, then (most likely) either:

a) Your fan clutch is broken.

or

b) Your radiator is so dirty (on the outside) that the air flow through it is insufficient to cause the fan clutch to sense the hot radiator.



About the only other possible cause for overheating is a lack of flow to the radiator. This can be caused by a failed water pump, clogged coolant passages (hard water will make this worse), a thermostat that isn't opening properly, etc.



It's also possible, but VERY unlikely, that your engine has so much crud built up in the coolant passages that the heat from the engine is not being transferred to the coolant. In that case, your engine would overheat, but you wouldn't know it because the temperature gauge reads water temperature. As I said, this case is very unlikely.



The first, and simplest, step should be to clean your radiator fins throroughly. If the fan clutch still doesn't work, then check it out. (Don't ask me how to check it. I'm sure someone else here will know though. I only know that if it's leaking viscous fluid, it's bad. )



On general principle I would flush the cooling system, but only because it's probably about due. Add some quality coolant and mix it with DISTILLED water. Don't use tap water, especially with any of the new extended life anti-freezes.



One last item: Water will transfer heat better than anti-freeze coolant. The reasons we don't run water are:

a) It freezes in cold weather and can break something.

and

b) It provides absolutely no corrosion protection.



If your truck never experiences cold temperatures, you can buy racing coolant (from Valvoline/Zerex, among others) and use it with distilled water to provide corrosion protection.



For an excellent (if I do say so myself) description on coolant system service, including flushing the system, see TDR #35, pages 76-81.



Good luck.



Loren

 

[jtwcummins]

when the truck is first started the clutch fan is engaged. the first few hundred feet driven the fan should sound like an airplane taking off then get quiet until coolant temp gets in the 170-180 range.

 

[TX-TowRig]

OK,

not all up on my fan clutch knowledge but from my understanding there is a viscous fluid inside that expands and contracts with temperture to engage the clutch. At startup, the engine is cold - why would the fan be engaged?



I have never heard the clutch turn on or off but have noticed it spinning. I also broke a belt the last time I went on a long trip and it overheated after the belt broke (didn't notice it untill the light came on). The fan must have been doing something because after I put my spare on it stayed normal. Now that I think about it, that would have stopped the water pump also. Guess it could be the clutch.



It only gets hot pulling heavy loads over the bigger passes (I had to turn on the heater and roll down the windows pulling over the pass west of Denver.

 

[Jamie Attridge]

Fuel Pressures seem good.

 

[jtwcummins]

every vehicle with a viscous fan clutch has it engaged when the vehicle is first started. When you start the truck in the morning and drive off it will be loud for a few hundred feet. It is noticeable, especially as the clutch starts slipping since temp is low and fluid in the clutch heats up and starts working. If you can't hear it the clutch is a problem. Another tell tale is the a/c output isn't as cold as it should be. Gauges will show abnormal pressures on high side.



Alot of vehicles are running around with bad fan clutch. As long as truck is moving w/o a load enough air gets through radiator to keep it cool. Under load the engine will heat up fairly qucikly if fan isn't working right. Enough speed will help keep cool. In town driving on a warm day w/air running the clutch fan should cycle regularly as coolant temp goes toward 180 degrees.

 

[TX-TowRig]

AC output sucks, I would like to replace the fan clutch



is the fan clutch a Cummins item? Is it convered under the 100,000 warrenty?



I have replaced the clutch master/slave in the Dodge parking lot, would do the same with this if it is free...