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i need some fan clutch help. local a/c place swapped out my oem fan clutch and replaced it. didnt ask them to but they did. now a/c temp rises at stop lights. the fan clutch they put on, the fins are much shorter than the fins in the picture in @Mopar1973Man "cooling system flush" article. does anyone know the brand/type/part number you have on your truck. i got 2 numbers from parts look up tool, need to find the proper fan clutch and get it cooling correctly again. the one i looked at from autozone have short fins also. for comparison, belt is 1-1/16" wide first picture is of @Mopar1973Man fan clutch fins second picture is from thoroughbred diesel site third and fourth picture is what is on my engine

Flushing the Coolant System Draining Coolant On a cool engine (less than 140*F) remove the radiator cap. Now at the bottom of the radiator, there is a drain valve on the radiator. The drain turns 1/2 turn then pulls outward slightly then continues to turn to drain. To drain the overflow bottom it just easier to remove the hose from the radiator neck and then pull the overflow bottle upwards from the fan shroud. Flushing Cooling System Flushing the cooling system you'll need to remove the thermostat. There are three 8mm head bolts holding the cover in place. Once the cover is removed you can lift the thermostat out. Now replace the thermostat cover and the upper hose. The upper hose should only be hooked to the thermostat housing. This will direct the water away from the fan for you. Now using a garden hose at full flow you can place it in the radiator fill neck. Start the truck. Allow the water to flow till all solid debris and coolant color is gone. The water should come out clear. You can lightly rev the engine to pump water forceful for bursts. This will help push water through the heater core flushing it as well. Take notice the radiator is removed in this flushing. Filling With Coolant Now as for coolant, our trucks came factory with green coolant. You may use green, yellow (universal) or orange (HOAT). Just remember "Universal Yellow" typically can be mixed with green or orange coolants in an emergency. NEVER mix green and orange coolants! If you are going to switch coolant make sure to flush the system thoroughly. I typically will park the truck on a nose down slope to attempt to get water out of the system. Cummins cooling system holds 6 gallons typically there is roughly a gallon trapped in the block. So the first gallon goes in full strength. All other coolant is mixed 50/50 before using after the first gallon. As for mixing coolant and water. Most suggest distilled water be used. Now back during the flushing, I had removed thermostat now you can fill the entire system till its right to the top of the block. This allows you to fill without having to burp the system later. Now once the block is full to the top you can install a new thermostat (suggested) or re-use your old thermostat. Re-assemble your thermostat housing. Make sure to use anti-seize on the thermostat bolts. Re-assemble your upper hose. Now finish topping off the cooling system with mixed coolant. Make sure to fill the overflow bottle to the FULL mark. Coolant Color & Condition I'm going to say don't open the radiator cap and look and say, "Yep it's still (whatever color) its still good." I've heard this a million times. If a customer is willing I drain their radiator and show them typically the first gallon comes out rusty brown, then may change back to coolant color slowly as it drains. What happens is every time you start your engine your passing high current flow through the block and tends to change the pH of the coolant just like changing a battery. So over time coolant will shift from pH of 7 and typically shift corrosive. Lime scale builds up typically is from not the water but from dissolving metals in the cooling system from the corrosive coolant. So don't get hung up on the idea of long interval coolants like HOAT or distilled water will protect you from scale build up. You can still get scale build up with distilled water or premixed coolants. Simply put if the coolant starts to darken in color it already failed. Personal Results As for my truck the first 150k miles was on green coolants. I was flushing the system every 30k miles or so. I will clearly state I've NEVER used distilled water in my truck. I've used either the irrigation water which is from a creek behind the house or from the well that is here on the property. No water here is treated or chlorinated. I'm now using "Universal Yellow Coolant" typically found as WalMart SuperTech, Prestone, and even Napa coolants. I've never had an overheat once. I've never had a heater core plug up. No limescale build up. 100k miles and 5 years.... Updated pictures... This is my cooling system after 9 years and 180K miles now... 2015 (13 years later) and 255k miles later.... Using Universal Yellow Coolants. Still no scale build up or cooling issues. This batch was extended to 70,000 roughly and 2 years. 350k miles 07/20/2018. Coolant change with NAPA Extended Life. July 2019 - 385k miles and replaced the oil cooler gasket. As you can see after 17 years of service and using tap water (well water) or creek water like I have there is zero scale build up yet. View full Cummins article

MY 2001 temp runs between 195 and 205 degrees. I changed thermostat, took radiator out flushed it and cleaned it and degreased it. Thought it might be running warm cause of blowbye blowing on radiator. Radiator schrouds were in good shape so im open to any suggestions. Thanks

Anyone have any opinions on what to use and how to go about this process? Thanks.

anyone know the dimensions of a radiator core on a 99 isb with ac

My 02 runs a little over the half way mark on the temp gauge at all times ( once its warm ) which kicks the clutch fan on was wondering if that's ok ?

Hello all I am new to this forum and hoping to find some insight. I have a 98.5 with the following mods,Edge juice with attitude, turbo modified by Gillette diesel, 275 RV injectors AFE intake and 4" turbo back.What i am seeing is some weird temp issues. Truck unloaded sitting at a stop light will start building temp for no reason starts at 180 and sometimes will go up to 190 or higher, ambient temp plays no factor will do it on a 55 deg morning or a 90 deg day. Differnt from one stop light to the next. Took to my local shop that helps me out strapped down to dyno duplicated problem but here is where it gets weird, one pull the truck wont break 190 with a 60% load applied via the dyno next pull truck truck hits 230 easily and once in a great while the truck will puff a tiny cloud of white then right back to black out of the exhaust. Fan clutch cycles normally, coolant shows no signs of combustion contamination not a 53 series block water pump looked great and truck uses absolutley no coolant. Radiator is five years old was clean externaly and passed flow test at the radiator shop earlier today. T-stat is probably 4 years old and this is the 3rd one but last time i replaced it the sympotoms were not like this. Engine has 102k on it and probably gets 3 to 5 k a year on it? i would really appreciate some feedbackThanks in advace

Just returned from our first camping trip of the year... first tow with the Quadzilla XZT+ (2000 tune). I don’t know if the XZT has any effect on the engine temperature. I am used to to running (empty) right on the thermostat, a needle width below the center mark (200 degrees). Towing, I previously ran about a needle width above that center mark. I saw the temp climb to 2 needle widths above on grades... but came down coasting / light throttle on the other side. So we arrived at the parking field, shifted to 4 high & were directed to the best spot. They wanted me to circle outside & “drive through” next to another vehicle which I did... but I could not get close enough. I was surprised to notice the temperature climbing to 220. I needed a couple of passes back & forth put the trailer in the right place. Just as I completed the last push back, the temp hit 240 & the RED warning light came on “Check Gauges”. I was in place, so I left the truck running & popped the hood to let the heat out while we set the jacks. The temp dropped to the thermostat level before I shut it off. I had checked all tire pressures before we left. I checked the belt, all fluids were ok. The ground was spongy... with the sod squishing 3” or so. I was gentle as possible with my stock Michelin tires. I didn’t see any breakthroughs though others mucked up other areas pretty good. We had extreem weather during our stay (a bucket in the truck bed was half full) and the ground was worse pulling out. The property owner had a tracked Bobcat on site & several vehicles had to be extracted. There was not a row in front of us initially, but later there was. When the vehicle between the trailer & the exit moved, I quickly got my truck into it. We were able to make the exit in one pass... I was gentle on the throttle but didn’t want to stop... I watched the temps even more carefully on the way home & it was as before... I’d say 200-205. My impression is that the cooling is marginal & that makes me uneasy. I’m planning a thermostat replacement & coolant flush... I know you guys have more experience than me... Ideas?

Alright been messing with this for a couple of weeks. Started when it first got cold. Noticed my heat was not as warm as usual. I checked my radiator and it was about half gallon low. After I filled it up I drove it and the heat seemed to be better. When I got home I noticed some antifreeze on the ground. Looked up there and found it dripping from the drain plug. Replaced the plug which I might add is a stupid design and pretty much worthless to actually drain your radiator. Why cant it be a pitcock drain. NOOOO it has to be some nasa frickin design with an O ring that doesn't actually work after you remove it the first time. :banghead: Sorry !! Anyway it wasn't the plug anyway but a leak in the radiator up a little higher behind the shroud. Ok now this is where I get lost. This is a closed system and it will build up pressure. Why is it just dripping ? Why isn't it spewing out making a mess ? Ok so I get a new radiator and install it. Replace the t-stat got it at O'reilly's and flush the engine and then disconnect the heater hoses and pour some clr in the heater hoses and let it sit in the heater core for about and 1 1/2 hours and then flush the heater core and reconnect the heater hose. Then fill the truck up with water and then I let her run a bit cause I want to make sure I am getting flow thru my heater core so I pull the hose off on the block side of the heater core and it is pumping good then I pull off the hose on the other side of the heater core and it comes shooting out. Then I drain it again and put the truck on slight upward hill and refilled with antifreeze. Also replaced the resistor on the blower. It went out in the middle of this. Also checked the door where you switch from AC to heat it works fine. Also checked the temp selector thingy underneath there it corresonds with adjusting the temp control. It spins around and stops.Take her for a spin the truck heats up to 190 heater seems warmer ? This truck has always heated up to 190 and would move a neeedles width either way while driving. The heater has always been hot and usually if I have plugged it in after a ten minute warm up it was very toasty. Ok now that I have replaced everything the truck is very slow to reach temp at idle. While driving @ 60mph my truck will reach 190 or just a hair more but when I slow down for a stop light the temp drops down to 160 or so and then as I accelerate the temp will slowly work back up to 190. My heat is warm at best but by no means is it hot. I just left work idiled in the parking lot talking to my friend for about 20 minutes and then drove home from work 25 miles mostly 60mph. I get home and pop the hood nothing is really hot at all. The radiator is not hot or even really warm. The upper hose has some pressure on it but it is not hard to squeeze. It's warm but not real hot. The heater hoses are a little warmer. So I touch the cap and it's not even warm so take the cap off and there is just no pressure at all I look into the radiator it is still full and there is no flow in the radiator at all. I feel stupid that I can't figure this out. The heater prob could be the core. But when I pulled the heater hoses I had good flow going in and out and the water was hot. (ouch dumbass). So I am thinking it is not the core. Why is there no noticable pressure at the cap ? Why is there no real pressure in the hoses ? If it is not pressuring up you would think you had a leak ? But I don't. Why is the temp of the water seemingly not very hot ? T-stat staying open ? Then I would think I would see the antifreeze flowing thru the radiator ? But I don't. Water pump not working ? Then I would think the truck would over heat or at least get hot ? It doesn't. For some reason the cooling system is not getting hot enough. It is not creating any pressure either. It is not cold enough here to require blocking the radiator. Never had a prob before. I am sure it is a simple fix but I am just at a loss as to what ? Why does it get to 190 and then drop back so far ? Why will it not hold the heat. Before it just stayed at 190 within a needles width either way. Sorry for the long post. Any help would be appreciated. Thanks Rob

Do the cummins brand of t stats have a fail safe?The question is when they go bad are they made to brake in the open position? My engine gets hot 190.The t stat housing is hot. The radiator fluid is cold.I am thinking water pump. The radiator and heater core were flushed in summer.

I used a flushing kit.. you know the kind where you put the T-fitting in the heater hose and then connect a garden hose.After running a bottle of radiator cleaner for a day, I drained and flushed as directed with heater on high.My question is this: while flushing, does the water really cycle through the entire system? I ask because it never really gets hot , and I'm assuming the thermostat never opens.So I'm gonna run straight water for a day, then drain again (maybe do that twice over a couple days)then add my distilled water/antifreeze.Anybody see any problem with this?Thanks, John

On my 2002 dodge diesel while swapping out my power steering fluid to synthetic today I noticed that 4 of the 7 blades on my fan clutch were cracked. Then while checking that out I noticed that the whole unit has some wobble to it where the belt goes around it. The clutch part has resistance when turning the fan either way so I'm thinking that may not be bad, but the rest of it has me concerned. So I'm wondering do you just replace the blades and I'm guessing a bearing on the pulley part that the belt goes around or do you buy the whole thing as a complete unit. Thanks Dwayne

Have an '01 3/4 with an automatic that I rebuilt the engine and ran across something if I can get some help with. The AC compressor bracket is also where the lower radiator hose connects and then bolts to the block and has a water jacket. Looking at it, it looks like it may take a gasket inside it. Does anyone know for sure and if so know what the name of it is?

Last time I was haulin a trailer I was pullin a 13k lb dump trailer and with my chip on high I could not keep the truck coolant very cool.was about ready to overheat. It runs about 190 all the time when not pullin and the fan runs alot.. I dont think it should run that hot when just drivin around. Maby i need to replace the thermostate. I cleaned the radiator and intercooler but it still run to hot I think. Is this normal to run that hot or am i just . Thanks

Well gang... I figure I better get the coolant change before winter. So I desided to pull the radiator and inspect it and was surprised to find the face plugged with mud and dirt... Not greasy grime like stock crankcase vents but just mud on the lower part... So I gave everything a good cleaning... Close up... The radiator... Flushing the block... Appearance of the block currently at 173K The intercooler face. Appearance of the block at 100K... Inside the radiator... Flushing...

I recently installed a coolant filter, and based on what I thought, and was told, at the time I plumbed it the way I did. I have the "pressure" coming from the head, and the "return" going to the block. I also recently realized that the flow of coolant is from the block, thru the head, and back to the pump, or radiator... So I am wondering if my filter is filtering backwords? So can anyone help confirm or deny this? Is the pressure in the head or the block greater? Thanks

Mine just went out with 60,000 miles on it. Will the 5.9 3rd gen pump work? The bolt holes are the same.

2002 3500...smelled antifreeze when driving..got home and saw that coolant was spraying in a small stream out of a tiny hole on the passengers side on the back of the cylinder head.Is this a small plug that came out or is it there to let you know there is a bigger problem like the weep hole on a water pump? thankx for any help!