:P My temperature gauge goes to 200 degrees and will stay there for a few minutes then drops back down to l70 or l80 and then slowly climbs back up to 200. This does this about every 5 minutes while traveling down the hwg. at 55 miles per hour. If I drive 70 mph on the freeway the fluctuation isn't nearly as much. Dealer says this is normal for cummins engines. Does anyone else have this temp. fluctuation like I do? This is my first experience on this web site, and I hope I am doing this right. The temperatures above that I am talking about, only do this when the truck is completely warmed up. We have a 2002 2500 Ram cc cummins diesel 4 x 2 with l5,000 miles on it. Waiting to hear from someone. waam - Holland, Mi. Diesel prices running from 1.45 to 1.53 per gallon in Holland

 

mine stays very steady at about 170 : the only change is when pulling a grade 6% or so whilt towing.<br>

 

This is &quot;normal&quot; for a stock Cummins in the Dodge trucks.<br>My engine temp will fluctuate between 150-160 to 190 and back for a while.<br>This is caused by the larger radiator up front. It cools the fluid to a point that when the thermostat opens, the new coolant is so cool that it closses the thermostat. <br>Then the cylcel repeats itself.<br><br>However, while Dodge says this is &quot;normal&quot; they do offer a different thermostat that eliminates this &quot;normal&quot; problem.<br>I dont have a part number for you, perhaps someone else on this site can give the thermostat part numbers.<br><br>It is normal.. just annoying.<br><br>Rich

 

Sounds like you've got the 190* thermostat.<br>Get the 180* at Cummins.

 

Welcome to the site waam!, As these guys have said it is a normal thing with that 190 thermostat. Dodge did release a TSB on it stating that it was caused by the cooling system being so effective that it shuts off like DieselDaze said.<br><br> They claim no damage can come from it and they do offer the 180 thermostat if it bothers you. Been doing that in mine since I bought it new in 96, my advice is to forget about and enjoy the truck!<br><br> If you still find yourself looking at the gauge too often then put the 180 thermostat in it for peace of mind.<br><br> Again welcome to DTR!

 

Waam, my truck has been doing the same cycling since 30 Nov 95. Mine gets close to 190 before it cycles back. May be that your gauge reads a few degrees high.

 

Just catching up from long weekend off and want to bring this one back up.<br><br>Waam, welcome and please post your truck description in your signature. We are very interested in everybody's truck, mods or not. <br><br>Good to see another from Michigan, I'm north of Grand Rapids. You just missed our first meet in Traverse City, but we'll be having more.

 

OK, gotta ask for 2 cents here. I thought we wanted our diesels to be warm because they run better when warm. Why would I want to put a cooler thermostat in it?<br>I don't really notice much fluctuation in my 99 except when I have the radiator partially blocked in the winter.<br><br><br>Chris

 

stamey This is the first diesel I ever had and the first truck I ever had where the temp. gauge moved as much as this one does, after it's warmed up, which takes about 12 to 15 miles. once it,s warmed up thats when the gauge would fluctuate up and down. The gauge goes the thickness of the needle past l90, and then drops down and repeats as I previously stated. I was told to enjoy my truck and not worry about it and I'm for sure not going to put something in front of my radiator to make it run warmer, or to heat up quicker. I don't think this is the place to ask this question, but I don't know where to ask it. I do not understand the clock times when this is posted. Maybe someone could explain this to me. Thanks everyone for all the info on my temp gauge. waam Holland, Mich. 30 degrees and cloudy 2002 Dodge 2500, quad cab, Almond color, 355 axle, limit slip. pulling 26 ft. Salem 5th wheel - no slide.

 

I can understand a little fluctuation, while the engine is reaching operating temperature, but I cannot understand it continuously fluctuating. Perhaps you have a bad thermostat, that's open all or nothing. When the thermostat is operating correctly it should open partially, enough to let the water flow and keep an even temperature. Your description sounds like the thermostat is slamming open and closed again when the cooler water hits it.<br>I run a plastic 'For Sale' sign in front of my radiator when it's below 50 to keep the truck warmer. It blocks 2/3 of the radiator and was much cheaper than a Winter Front, plus it's behind the Intercooler and the front of the truck looks no different.<br>To test like your conditions I'll pull that out and ride around a little in the morning and see what happens.<br><br>Chris

 

I agree with Stamey. Mine flucuates too on warm up,with colder temps. Never noticed in the summer. I would try to get as much heat to the motor as possible. If your stat is bad i would replace it with another 190 F. Despite what the TSB says. I use a cold weather front and my temp guage has never climbed past 190 even in outside temps of up to 65 F. Seems to warm it up faster too. Just a mechanics $ .02 TGCTD

 

OK, pulled the Fors Sale sign &quot;winter front&quot; this morning and went on a 40 minutes drive. In 35 degree weather I reached operating temp in about 11 minutes, at 65 mph, and then observed the fluctuation. By this time I was in the city so it was 45-55 mph with stop and go. Guessing at it due to the lack of numbers on the gauge, I figure it was slowly moving between 190 and 170. It did this continuously. If this is what your is doing, take my advice, put a winter front on or get a sign like I did. I don't have that fluctuation with my radiator blocked partially. It goes just a little over 190 and then drops back down. It was a cheap fix at first because I didn't know where to get a winter front for my truck, or even what it was called at the time, but it does so well I see no reason to change it. You just have to remember to remove it if the temp gauge tells you to (the engine going up over 190 for any length of time).<br>If you still have continuous fluctuation after doing this, you should look hard at the thermostat.<br><br><br>Chris

 

If you do use a 4 sale sign to block your radator (winter front) its a good ideal to cut a round circle in the center at about the center of the fan...Ive seen big block cummins that have broken fan blades off by the driver puttin card board in front of the radator off center...my .02 cents

 

[quote author=pappyman link=board=4;threadid=8579;start=0#85205 date=1040991249]<br>If you do use a 4 sale sign to block your radator (winter front) its a good ideal to cut a round circle in the center at about the center of the fan...Ive seen big block cummins that have broken fan blades off by the driver puttin card board in front of the radator off center...my .02 cents<br>[/quote]<br><br>Pappyman,<br>Any idea why cardboard would have anything to do with the fan blades coming off? My sign only covers 2/3 of the radiator. I didn't figure it would be wise to cover the whole thing. Even the big trucks I see with their winter fronts closed up completely must have a little air getting into that radiator through body gaps so my blocking the radiator so close, where no air could get through, was not a good idea. The 2/3 blocked has done a fine job so far. The temp manintain an even keel when driving and cools very little when idling.<br><br>Chris<br>

 

Winter fronts go on the grill and the space between that and the radator are enuff to not cause the fan to draw uneven air thru the radator... if you block the radator the fan still try's to draw air thur...ie: you block 1/2 of the radator the fan blades on the unblocked part draw air and flex this can cause the blades to flex unevenly...which can stress the blades and start a crack...if you cover the whole radator and cut a circle in the center it keeps the air flow even thru the radator and no uneven flex on the blades....now this is only if your engine gets hot enuff for the fan to engauge and most times the fan doesnt engauge in the winter weather...try to pull out cardboard (4 sale sign) from the front of a radator when the fan is engauge and RPM's are high its hard to do...just my .02 cents