Engine/Transmission (1998.5 - 2002) Running hot. Did I screw up?

[milehiscott]

I recently drove to the south part of Colorado. On the Interstate I was holding a steady 75-80 mph. Mostly flat, some rolling hills, temp was in the low 90's and I was empty. The temp guage was at 190* and kept climbing up pretty high and then I would hear the fan kick in and bring it back down to 190*. I changed my coolant last fall, so this is my first hot day run with the new coolant.

Did I screw up somehow? It seems to be running hot for empty and flat. I'm going to CA and NV in July and don't want to overheat in the desert.

Scott

 

[bmoeller]

Did you replace the thermostat also at the same time? May need to if not.

 

[lmills]

I frequently hear my fan kick in when I am running empty. Usually it is on a particlar steep mountain climb that I make twice a day. It is just the clutch locking up when the temperature is rising. I would have to say that everything sounds to be in working order. Maybe you should do what I have been considering, drop in a 160 thermostat. That should help matters.

 

[athompson]

Mine doesn't budge from 190...

even when the tempurature was over 110. But maybe my fan's running all the time at those temps. You should check that you got all the air out, too.

 

[milehiscott]

Moeller,

I didn't change the thermostat. Is it maybe sticking closed?





Thompson,

Am I correct in thinking that after this much time all of the air is "burped" out and I just top it off?

Scott

 

[TowPro]

my brandnew 2002 does the same thing towing at those speeds. It runs 210 all the time towing fast, 190 the rest of the time.

 

[bmoeller]

Originally posted by milehiscott

Moeller,

I didn't change the thermostat. Is it maybe sticking closed?

Scott

Had it happen before on the '96 GMC 2500 w/350 that my boss has. His got ALOT hotter than yours. He told me it was getting a little WARM not HOT! He wound up ruining his intake manifold. Water would just pour out of it.



I have new t-stat to put in mine.

 

[rweis]

160* stat? Have not heard of that low a value before. Do you have which years and a part number? I thought a 180* was as low as you could get for the CTD.



Bob Weis

 

[lmills]

Your right. 160* is what I meant to say.

 

[BK]

I've seen them run hot if there is still air in the system.

Is the radiator filled? after a run like that , if there is a lot of air, the radiator will be low... . and if it's too low it wont suck from the overflow tank.

 

[krs]

milehiscott,

When you change the coolant you should fill the radiator then start the truck with the radiator cap off and run it until the thermostat opens. It might take a long time. You can usually watch it happen but if you miss it the coolant will get lower after. Then fill the radiator with the engine still running and cap it. On most systems you can see the coolant rushing by the radiator cap opening when the engine is revved up and down. Then bring the recovery bottle up to the 'warm' mark.



If you didn't make sure that the thermostat opened you're probably running low on coolant now. It won't 'burp' out of the recovery system if it is low in the first place. Check it in the radiator not in the bottle.

 

[milehiscott]

You guys were right. I was low on coolant. I burped the system and topped it off today. I'm going to be in the mountains tomorrow, I'll see if it is any better.

Thanks!!!!

Scott

 

[Loren]

milehiscott,



Your thermostat is working. If it weren't, your fan would have no effect on the temperature of the coolant in the engine.



You may have to burp the radiator once or twice more before it fills completely. You can tell when that has occurred by checking the coolant overflow bottle.



After the engine has cooled, the tube part of the bottle that attaches to the small hose to the radiator filler will be completely full of coolant. If there is still air showing in this part of the overflow bottle, you need to add more coolant to the radiator. The presence of air indicates that the radiator is not yet sucking coolant from the overflow bottle.



Loren

 

[kbond]

How do you burp?

Originally posted by milehiscott

You guys were right. I was low on coolant. I burped the system and topped it off today. I'm going to be in the mountains tomorrow, I'll see if it is any better.

Thanks!!!!

Scott

Probably a silly question but I have to ask,



How do you burp the system?

 

[Loren]

"Burping" the radiator refers to getting all the air out of it. The procedure is to fill it as full as you can through the radiator cap, not the overflow bottle.



As suggested previously, you can run the engine until the thermostat opens and then add more coolant until it's full, but that step is supposedly not required on our engines. They have a "jiggle pin" (I think that's what it's called) to release air so you can fill the radiator. The last couple of gallons will go in very slowly, however.



After you have the system as full as you can get it, put the cap back on and go for a drive. You need to heat the coolant to operating temperature. This expands the coolant and forces air out past the radiator cap into the overflow bottle.



Note that if there is too much air in the radiator, the 16 psi cap will prevent it from escaping. The air will pressurize to, say, 12 psi and then when the engine cools, it will expand again to drop back to normal, atmospheric, pressure. No air will be released in that case. You need to get sufficient coolant into the system to pressurize the remaining air to greater than 16 psi.



Allow the engine to cool. This will cause the coolant to contract, and as it does so it will draw additional coolant into the radiator from the overflow bottle. If the tube on the bottle (see my previous post) still has air in it, you will need to repeat the entire process.



Do this as many times as necessary to force all the air from the system. If you are patient when filling the system the first time, you should have to do this only once.



Loren

 

[Turbo Tim 1]

The thermostat on my old 93 had the jiggle pins but the new one I just put in my 01 and the one I took out have two small holes in them that allow air to escape. I try to park with the front higher than the back so that the radiator is the highest point in the system (not alot, just a few inches) and then fill everything up, letting it sit after it comes to the radiator neck. after 20-30 mintues the level drops a little and I fill it back up, I repeat this step a couple times. I also squeeze the radiator hoses and move them around to fill and spots that may trap air. I then fill the bottle just over the full line. I've used this method a few times and have never had to add any coolant to the system and the bottle ends up an inch or two below the full line.

 

[KevinK]

I just towed our fifth wheel from Denver to Leadville and had temp problems. The temp would steadily climb until my check gauges light came on and the temp would hit 240*. Luckily, I was always very close to the top of a hill when it got hot and it would cool down as I leveled out. I had the same problem last year and the dealer replaced the fan clutch and put in a new 180* thermostat. I have never heard the fan come on (old or new fan clutch). How obvious should it be? It's getting a bit frustrating trying to pull hills and having to worry about the truck over heating. Any help would be appreciated. By the way, my coolant level is correct.





Thanks,

Kevin

 

[bmoeller]

The fan is usually loud enough to hear over the engine. I see you have a 4" exhaust and a mod. turbo. Those may make the truck loud enough to drown it out. Don't know what you have for a muffler, if any.



I only hear mine when the truck is still cold 'til the fan clutch warms up enough to let it freewheel. The 6. 9L in my Ford is the same way and is louder than the one on the Cummins.



If you stop at the top of the hill to let it cool down, does it feel like is that hot? Still may be an off chance the thermostat is still not working quite right also, even if fairly new.



Is your guage working properly?



My uncle had a 860 Massey combine that had a bad coolant temp. sensor. It would cause the combine to shut down unless you hit the shutdown override switch fast enough. Stuck a thermometer in the radiator and it was actually 190*, not the 220* or so it thought it was.

 

[KevinK]

I do believe that it's running as hot as the gauge states. I can watch the transmission temp follow the water temp. The transmission will heat up to about 210* when the truck hits 240*. I can drive all day on flat ground and I never get above 190*.



I've got an appointment with the dealer on Friday (It's till under warrantee from last year), so I'll see what they think. When it's cold, the fan clutch is fairly tight. I haven't checked it when it's hot.



Kevin

 

[bmoeller]

Do the radiator and coolers fins need power washed?