I have a 2002 7.3 with 180,000 miles it has been running warmer than usual (AROUND 3/4 TO HALF ON TEMP GAUGE) with out a heavy load.The other day it was about 80 degrees in Florida on flat terrain,after i turned my air on which cuts out after 10-15 minutes, I notice my temp starting to rise about 3/4 on temp gauge, after i turned off air temp came down some, turned on heater it came back to half on temp gauge . Temp was going back and forth from 1/2 to 3/4 depending on speed.(45-60 mph).Drove 20 miles and got home checked coolant tank and was ok and was circulating and fan was turning and seemed a little hot .I squeezed radiator hoses they seem stiff.Later after cooling off my coolant level was ok. I changed my coolant tank about a week prior due to a leak and was running warmer then. I don't know were to start other that a radiator flush ,maybe thermostat ?Any suggestions on how to check fan,water pump?Any advise would be helpful. On a shoestring budget being a landscaper-nurseryman with this great economy.

 

the dash gauge is not accurate.
the thermostat maybe bad.

 

Check the easiest things first. Clean out your radiator, intercooler, and AC condenser. They can look pretty clean but actually be really full of crud. (especially down south with bugs all year around) With your engine completely cold shoot water from the fan side forward thru the radiator. I wouldn't use a pressure washer. It is too easy to bend your fins and cause more problems. Just the highest pressure you can get from a garden hose.
Next check your fan clutch. There should be very very very little or no play in the fan when you try to rock it back and fourth. If it is sloppy and wobbly that is your problem, they are quite common to die on these rigs especially after 180K. After that start thinking T-stat or something more in depth.
Do you know why your A/C is cutting out? Have you had the problem diagnosed? That can happen really quickly too with a clogged condenser..

 

Still having problems. Spayed out the backside of radiator in between the fan was a little dirty, spayed out the ac condenser pad it was pretty dirty with love bugs hopping this was my problem,used simple green.Changed the thermostat it was stuck about 1/8'' open when replacing ,it closed all the way when i pried on it .The fan does not seem to have any play in it your can spin it with resistance.Don't see play from side to side when pulling back. Drove about 20 miles truck ran at normal temp.Stopped for a 1 1/2 hours drove about 20 miles with ac on ,after about 18 miles my ac was losing coldness and temp was starting to rise ,turned on heat to help bring temp down,pulled next to a hose a slowly hosed off ac condenser and front of radiator got temp back to half way on gauge, notice antifreeze on top of radiator but didn't see no leaks (DEGAS CAP MAYBE)fan was turning ok. Radiator hoses hot ,coolant circulating through coolant tank.AC compressor was warm. AC seemed to blow a little cooler with bugs out of condenser pad but still cut out ,and know i haven't had ac diagnosed.

 

First. How many miles are on this machine????
Your AC compressor has a AIR GAP specification of .014 inches to .026 inches. If the gap is too much then the clutch will not stay locked in.
With the truck not running and the key in the on position turn the ac on and listen for the ac clutch to pull in. Now with the engine not running and the clutch pulled in measure the air gap. If it is greater than .026 then you need to adjust the shims. Let's just say your gap is .038 for measuring purposes which puts you about .012 over the spec. With the clutch still pulled in loosen the 8mm(head) bolt(bolt is actually 6mm) in the middle of the compressor and loosen but not all the way. Now turn off the key so you do not drain the battery and loosen the bolt the rest of the way. Measure the shims. Lets just say that the shims are.078 ....You need to remove .012 from each shim to get back just within spec. So, if you remove .020 from each shim that should put your gap back to .018 inches. Just use a file or some emory cloth to remove the excess. Remove the excess very slowly so you do not go over. Check with Orileys or Advance Auto to see if they have a AC shim pack that you can buy and then all you need to do is measure the new shims and find the ones that put you back into spec if you don't want to sand or file the old ones.
After you put the shims back in, put some blue locktite on the three end threads of the bolt and start to tighten. You will need to place the key in the run position and turn the ac on again without the engine running so the clutch does not spin to get the bolt tightened back up. I really can not go into any more detail than that.
Dwayne

 

On a side note. I pulled my intercooler a few weeks ago to get the excess oil out of my Intercooler. I rinsed it out and blew out the coils on the outside with compressed air. It was badly clogged with clay dirt and a bunch of clay buildup. I rinsed it with water and simply green and blew it out completely. I had already straightened all the fins on my ac condenser but I was curious how much buildup I had on the condenser and the radiator. I blew compressed air into the radiator fin area and a complete dust storm erupted. I let the compressor cycle to full air pressure again and kept blowing high pressure air until the dust cloud was not visible. I placed a 20 inch box fan above the engine and blew it downward to keep most of the dust out of the top of the engine compartment. The crap went everywhere but the 20 inch fan directed most of it to the ground. I then blew out the AC condenser coil from the intercooler side to the front of the truck and got the same results. I have 190K on my truck and only 6K of those miles are mine in the past 6 years. I am happy to say that my ac blows really cold without the ac mod in place but I am still going to install the valve. I guess the previous owner lived in a clay type of environment and all three heat exchangers were pretty badly fouled out. The brace above the intercooler was a slight pain to pull because I had to cut a small corner of the frame that the brace pushes down into. After I cut the small piece on each side that the brace pushes into it came out with a little bit of prying. The intercooler comes out fairly easily but you have to help it around your AC hard lines. I am really happy I pulled the intercooler to rinse out the oil because I was able to get all the heat exchangers fairly clean with compressed air first and then some simply green and more compressed air. I hope this explanation is not tooooooo lengthy but I like to be as detailed as possible just in case I am dealing with someone who does not turn a wrench for a living like myself.
Dwayne

 

The intercooler? that is in wedged between the the radiator and the ac condenser pad ? Wasn't able to clean out like you said because of location. HAYNES says remove radiator but DWAYNE your idea sounds a little easier
My 7.3 has 180,000 miles.It is pretty sandy here.Sorry can't fiquere how to get mods to come up on page.Looks like i need to check out my intercoller .I did notice that my ac compressor clutch spun free with no resistance and then after looking at my keigbors 2000 7.3 his ac clutch had resistance. And when i checked mine again the second time, mine had resistance. So yea i will have to check the air gap. seems like my fan clutch has the same resistance as my neighbors. also took a mirror and looked an bearings in fan clutch looked ok, no spilt grease . I seen the tread on the air gap for ac the other day some where on here that sound to simple.But if something else is bad with ac can that cause motor to run warm.Thanks james

 

Lack of air flow thru the radiator or low/lack of flow thru the cooling pump can cause your problem. You already replaced the thermostat so that is not on the list for now.
We are back to airflow or bad fan clutch or low flow from water pump.
The reason I wrote up about the removal of the intercooler was that it cost me nothing but my time, some simply green and some electricity for my air compressor along with an air nozzle that looks like this from harbor freight:
4" Air Blow Gun
Don't be worried. You can purchase a blow gun from walmart with campbell hausfeld name for more. I used a cutoff tool with a 1/16 inch cut off wheel to cut the small corners of the frame to get the intercooler brace off. What better place to purchase a cutoff tool but Harbor Freight:
3" Variable Speed Air Cutter
The cut off wheels also:
3" Cut-off Wheels for Metal, Pack of 10
Remember your safety glasses and some long, large screwdrivers and a tiny hammer.
I gotta get to bed for now. I will take a picture later of the small frame corner I cut out on each side to get the intercooler out. I just spray painted over the cuts to keep the rust down.
Dwayne

 

Thanks again for the ideas.I pulled the plastic fender cover half way off of the top the radiator , condenser so i could get to front of radiator and back of ac condenser radiator looked clean ac condenser had little grass looking stuff but not bad. hosed out used simple green. Also cleaned and lubicated my mac air filter it was due.Ac condnesor pad does have a few bent fins(3-5%)has been for 80,000 miles since i own truck.I will check air flow throught radiator tommorow with air compressor,it sound like maybe my water pump?Althought Older type water pump i have changed in gassers usally leaked(1973'S and up)but were in ford inline6, 351, 361,or chevy 350.Haven't had to work on to many of my diesels other than my 97 6.3 gmc.But its a totally differant world.Heck I chold sit in that motor compartment.I change glow plugs in a hour or two .The 7.3 is a lot more cramped . Yea i think digging ditches is a better trade lol.

 

While it is possible your water pump is getting there normally unless it is leaking or making noise they are usually fine. Your thermostat is the most likely issue as long as you are sure your radiator is clean as a whistle. For what they cost go ahead and change the thermostat and flush the whole system out. While your system is empty pop the belt off and give the WP a spin see how it feels/sounds. If there is any bearing noise or it feels gravely it should be changed while you have the coolant drained.
I am sure almost everybody here would agree if you replace the T-stat or water pump spend the extra money and get OE parts, they are worth the money when it comes to durability and fit.

 

What brand thermostat did you replace it with?

The MOST likely problem in this situation since you have already replaced the thermostat is that your radiator is clogged internally. I am sure you are flowing water properly thru your pump as the above member stated .
Blow the outside heat exchangers out with compressed air and see how much that helps. I was going with the cheap method of wrenching and compressed air first. I don't know how much a new radiator or taking your radiator to a radiator shop to have them properly flush it out or ROD it out cost. I know it is a lot cheaper than overheating the truck and having to pay $1600-$2000 to rebuild the engine

Keep us posted with the issues and let us know what you have done.
Dwayne

 

All good suggestions, except maybe the t-stat... My bet is fan clutch. Ive haf 2 fail.

Do you ever hear it engage? Mine still would engage, but late. AFAIK there is no 'test' for this but its an expensive part so do the cleaning stuff first.

 

All good suggestions, except maybe the t-stat... My bet is fan clutch. Ive haf 2 fail.

Do you ever hear it engage? Mine still would engage, but late. AFAIK there is no 'test' for this but its an expensive part so do the cleaning stuff first.

 

time for some gauges. Mine went haywire, even though i have a coolant temp gauge, i still wanted the oem one to work as well. If replacing the sensor, YOU NEED this #F65Z-10884-AA

 

When you changed your thermostat and coolant tank, what coolant did you use and what coolant was in there originally?