Engine/Transmission (1998.5 - 2002) Water Temps while Towing....Long

[klaybus]

Here's my story if you have time. We went to Eastern Washington this Labor Day weekend & it was warm, 85. While crossing over Snoqualmie Pass in Washington, my water temps reached 200-205 degrees making me pull over & let the engine idle & cool down. When we reached Ellensburg Wa. I went to the local Dodge dealer & bought a new 180 deg T-Stat & installed it. Not loaded the truck ran great. Temps ran on average between 180-190 in 95+ degree weather with the A\C on. While coming home going West over Snoqualmie pass, temps began to climb again. I shut down the A\C, turned the heater on & maintained 190 degrees & once over the pass turned the A\C back on and the water temps stayed between 180-190.

When I got home I read my service manual & followed the procedure for checking to see if my fan was operating & it appeared to be. With the radiator blocked it came on about 180-185 degrees & turned off shortly after the blockage was removed. I should mention that I installed the new 180 degree T-Stat but I have no idea what kinda shape the coolant is in or if it has ever been changed. I bought the truck at 89k miles & it's now at 110k. Coolant is very green & my trailer weighs approx 6500 lbs.

When I bought the new T-Stat I also purchased some overpriced Mopar coolant from the dealer. Is it any good for our Diesel engines? The parts person said it would be fine. I haven't used any due to losing next to nothing when doing the t-stat swap.

Any ideas what may be causing my overheating problems when towing? Fresh coolant I guess might help... . Huh?



Clay

 

[Whitmore]

Clay, I would do a coolant flush and go back with new Mopar coolant, see if that helps any. Also look from under the truck up between the radiator and the intercooler to see if any buildup, I did this on mine and found that when the oil puke bottle got full it made a mess there and then dirt clung to it restricting air flow... ... ... ..... I dont think 205 is much of a problem though.



Cheers, Kevin

 

[ProspectorTim]

Coolant flush ( replace hoses & belt while you are at it, for peace of mind). Clean the bugs & such from the raditor. Replace the radiator cap.



I'm not famiiar with that pass, but the next question would be if you had to downshift to 2nd? and if so, does your valve-body enable 2nd gear lock-up? Stock, 2nd gear will generate a lot of heat pulling loads up mountain passes with torque converter unlocked.



see: How to cook a transmission well done

 

[hensign]

Fan operation

Check that fan better..... If you had to get home and check it, it probaly isnt working. On the highway when mine comes on it sounds like a jet is hovering over my truck. You should hear it howling when climbing then it should calm down after the hill. I can even get mine to come on from getting up too close to other traffic especially big trucks since they superheat the air coming out under them. Plus you should put in additive with the coolant to cut down cavitaion/erosion.

 

[SEmerson]

That doesn't sound too hot. 205 is most drivable many new cars run 210 -220 all the time. Both of my trucks will make alot of heat climbing. Try to keep the converter lock aswell climbing. Otherwise all the extra heat from the trans goes to the heat exchanger.

 

[klaybus]

High Temps

Preceptor Tim:



Snoqualmie Pass isn't so steep that I had to downshift into 2nd but when my water temp started climbing I just took my foot out of it & pulled over ASAP to avoid boiling over.



Hensign:



When I'm on the road I have a pretty fair amount of road noise coming from my tires, thats why I have a hard time hearing my fan. When I did the test per the "Service Manual" it seemed to be working properly. Although I didn't have a temp probe to stick down by the radiator, when I blocked off the front of the radiator, the fan came on at about 180 degrees +-, & ran for a few minutes & then shut down. Per "Cummins" website it states that no "additive" is needed for the Cummins ISB engine.



Thanks for the input. I think I'll do the flushing and refill with fresh coolant & see how I do next weekend.



Clay

 

[Loren]

Clay,



Your truck didn't overheat. It just got a little warmer than normal, which can be expected when towing in the mountains in hot weather.



190 degrees is the middle of the normal range on both my 2000 and my 1995 trucks' temperature gauges. The red line on my 2000 truck is 240 degrees and on the 1995 it's 230 degrees. According to Dodge's procedures for testing the standard thermostat, it will not be fully open until the temperature reaches 203 degrees. You can easily go well above water's 212 degree boiling point in a cooling system because the system is pressurized.



I wouldn't even worry about it until the temperature moved above my normal range, indicated by the white band on the gauge.



I don't know the temperature rating of the factory thermostat, but it is supposed to start to open at 180 degrees and be fully open at 203 degrees. Installing a lower-temperature thermostat will not solve overheating problems, assuming your original one is working properly. A lower-temperature thermostat will merely cause the engine to run at a cooler, and less efficient, temperature during normal operation. The reason a lower-temperature thermostat will not cure overheating is because any (operating) thermostat will be fully open by the time the engine is overheating.



I would say that you don't have a problem.



I would, however, change the coolant because you don't know how long it has been in the engine. Any name brand coolant is fine, but change it according to the maintenance schedule indicated for that type. The reason to change the coolant is not to cure overheating problems, but rather to maintain the corrosion protection for the cooling system.



Loren

 

[rashwor]

Here are my experieces....

I changed my coolant and thermostat back in July. Before the change, it would run up to about 200 - 205* when towing heavy in the Texas heat (95+*). Prior to this summer, it was hard to get it above 190*, so I cleaned the radiator to no avail. Next steps were as follows.



I replaced the thermostat with a 180* thermostat (180* came out, so I did not have a 190* originally).



I drained the coolant and refilled with the Cummins Compleat ES. It is the pretty blue color! I did the coolant and thermostat changes at the same time, so I can't tell you which one made the difference.



The results are that no matter what, the coolant temp is yet to exceed 190* even towing heavy. The truck runs between 170 - 180* now when not loaded.



I am very happy with the results.

 

[jmtandem]

klaybus,



I was a little surprised coming to an '01 from a 91. 5 to see the temp gauge move at all. The 91. 5 would stay in one spot all the time after driven a few miles, camper or not, climbing or not, towing or not or even hot or cold outside air. The '01 gauge moves around some and will normally hang just one needle width on the cool side of the half way point on the gauge for normal use. But climbing a hill with a cabover camper on a hot day causes the gauge to climb to about one or two gauge widths hot of the middle. We have serious hills here that can climb 3000 feet in eight or nine miles so it is expected to see some operating temps climb. AC on or off doesn't register much on the gauge. A minute or two after the mountain pass is crested the gauge goes back to normal operations. My fan is not that loud that I can easily hear it if the windows are down and there is road noise. The fan on my '91. 5 actually had a roar sound to it.

 

[Diesel Gunner]

Servicing the cooling system sounds like a good idea. To be quite honest, you don't have any problems. I just returned from a weekend in the mountains with my TT and coming home the OAT gauge registered as high as 106*. I heard my fan clutch engage many times and the temp gauge wiggled back and forth from the center mark to two needle widths past it.



In addition my transmission and rear end temps went up as high as 190*. Relax, everything is just as it should be.

 

[Bob Wagner]

Klay, have you relocated your blowby bottle? And 275's and VA will have you over Snoqualmie in third



I just went over in OD with my 10k+ 5er , yeah I forgot to get out of OD before the crest



Never saw more than 190F

 

[klaybus]

Heat

Bob & Everyone... .

On my 99 I don't have a blow by bottle but I did however lower the tube within 8" of the ground to keep the oil blow by away from the engine & radiator. I stopped by my brothers (Sixpack) place & he pointed out to me that the front of my radiator had some dirt & crap on it where my fan sucked it on. I'm thinking that it was never a problem before because the A\C wasn't working & the temps outside were much cooler.

While I was at Phils house his neighbor came over with some test strips to test my coolant protection level & it was poor! 10 degrees above freezing with little corrosion protection... . I took compressed air & blew off the crap on the front of my radiator & hoping this improves things. Tomorrow I hope to get off early enough to where I can flush the fluid & add new.

After work tomorrow if it's warm outside I will run the A\C again & see what the temps do again. I plan on just buying two more gallons of the Mopar Coolant since I have one already & stopping to buy three gallons of distilled water to mix with the coolant after I flush with tap water.

I'll keep you posted as to how things turn out.



Thanks,

Clay

 

[SEmerson]

I did try some of that water wetter additive. It does help a little. It causes the water to tranfer heat better. Also remember that your engine will make in heat about 1/3 of the energy from the fuel. So as you add power on a hill (like bombs) cooling will be harder given that you pull fast with your added power.

 

[jmtandem]

Klaybus,



It sounds like you need to change the coolant, however, if your temps quickly return to normal after cresting the summit or on the level you do not likely have a overtemp problem. Engines are expectd to generate heat climbing when working harder and if temps come back down quickly going downhill you are probably all right. My gauge actually goes about two needle widths past the 190 middle indicator every morning as it warms up and then the gauge drops back to normal about one gauge width on the coolside of 190. However, I also need to check to see what crap is near the crankcase breather tube and cannister. Last week I cleaned the cannister and gunk was everywhere. If some of it is on the radiator I will flush it out. The location of the cannister is ridiculous.

 

[Dsl_Duo]

I just returned from a 3000 mile trip up Hwy 101 to Washington and back down I5 to Southern California.



My truck ran Great going up and had plenty of go power all within the normal heat operating ranges of both the water and the EGT. I could maintain quite resonable speeds and pass all of the slow pokes struggling up the hills.



But, some time on the way back something changed!! I couldn't climb at all without pegging the EGT. So I down shift and slowing climg over the hills. My wife said she was glad we bought the magic box (A Edge Comp without the pump wire attached), we had become one of the "slow pokes"!



At an over night stop I cleaned / reoiled my air filter, made sure there were not any excessive bugs or otherwise clogging my radiator and I got rid of the oil bottle a year ago.



Yes, my water was hot, but only about 205- 210 degrees. What I am confused by is why my EGT runs so hot now. I can peg it in third gear from a stop where before it would run out of RPM range before it hit 8-900 degrees. (All of the above is with my 11000 lb fifthwheel in tow. )



Any ideas??



Dsl_Duo

 

[ProspectorTim]

Low power, high EGT: Check the clamps on the intercooler hoses!

 

[klaybus]

Temp Update

Coming home from work today in 85 degree weather with the A\C set on MAX the truck ran cool... . About 180 degrees at 2300 RPM. Just blowing the crap off my radiator seemed to do the trick.

After work I drained the radiator, refilled, ran to operating temp, drained... . Refilled, Ran, Drained again... ... You get the picture. After three flushes the water was clean with no visible color of the coolant. I filled the system per Steve St. Laurents directions & was able to get 4. 5 gallons back in the cooling system. I don't know how he got almost 5. 5 gallons but mine would only accept 4. 5. Maybe after running a while I can add more coolant through the overflow\ refill bottle.

Pulled the 5er to the rest-stop to dump the waste tanks. Temp outside was close to 80 degrees, I had the A\C on MAX, ran it hard!! Water temps peaked at 185... I think I've got the temp issues handled. Gotta work this weekend so camping is out until next weekend. Then the true test will happen.

Thanks for all the input! Gotta love TDR!



Clay

 

[C.Wood]

Check the clamps on your intercooler hoses. One of mine blew (The clamp popped off, compromising the seal) while towing and my EGT's went through the roof.