Does Cummins make a 180 degree thermostat for the 02 HO? I called Cummins and they told me that the 180 degree part #3954194 I bought for my 98 24V wouldn't work in the 02. I tow heavy and would like to lower the temp. Any ideas?

 

bpk...Since nobody has responded to your post, I know some after market vendors did offer at one time a 180 temp. thermostat. I'm not sure if any benefit was gained by the reduction of running temp in our cummins engine. As far as performance, ( fuel burning) proper engine temp is required. Concerns of high heat have shifted to exhaust temp control (EGT&quot;S) vs engine temp. Properly, maintained cooling system should control engine heat. As I don't tow much, perhaps those that do may have some real benefits of a lower temp. thermostat that I'm not aware of???<br><br>Steve

 

Thanks for your interest HeberRam. The 02 seems to warm up a little quicker than my 98 and although I purchased a 180 degree for the 98 and never did put it in, I just thought it might keep the temps down a little and the motor may not heat sink as much. I haven't pulled with this truck yet, so I may not even have a problem. Thanks

 

A couple of thoughts here on the 'stat question, bpk. Without changing the cooling system itself (radiator efficiency and all of that), the best thing you can do to keep things cool is to maximize flow. Seems to me there are such things as high flow thermostats -- maybe we already have these in our trucks I don't know. But anything you can do to increase the coolant flow rate will improve cooling efficiency -- the ability of the radiator to remove heat from the engine and dump this energy into the outside air.<br><br>I havent actually verified this, but in my opinion a lower stat temp will not help cooling. What it does is lower the engine's running operating temperature under all conditions -- do you want to do that? Thing is, heat transfer theory says that such a lower temperature will be more difficult to maintain than the higher one was (because the engine's temperature is closer to that of the outside air). There is no improvement in cooling efficiency, and the newer stat will do nothing to the maximum (coolant) temperature when you are pushing it -- that is, either stat, when fully open, is 'out of the picture' so to speak and the one permitting the highest flow rate will cool things the best, regardless of its opening temperature. <br><br>In other words, when you're pulling up a hard, long grade, and your engine temp creeps up (are you experiencing this?) -- a lower 'stat temp won't help. <br><br>In my opinion, the best approach is to keep the stock coolant temperature, and watch out for high EGTs.

 

I always heard that the Dodge ISB was the only one that had a 190 t-stat and that all others were 180's. Can anyone confirm this?

 

Cummins doesn't have a part # for a 180' for a 2002. I took the a TSB that had 2 DC part #'s and he look them up and they don't tell the temp. Maybe I'm making to much of this??<br>I agree that the cooling and the lower EGT's all together to give you the final number. Like I said , I was just trying to lower the temps to start with. &quot; Maybe that didn't come out right&quot;. Tanks for all your help. Anybody try &quot;Water Weter&quot;? I'm going to give it a try.

 

<br><br>This is a very good point. High EGT's make your truck run hot. Keep them down and your coolant system should be able to do the rest. I do know that you can run a 180* thermostat, dont know if it will do what your looking for. I always run cooler stats in my stuff but thats because heat means lower power output. It used to be for every 10* you lower or raise the temps you power goes up or down by 1%. Not much unless you talking about 300-400hp. I havent changed the stat in this truck because it rides on 185* unless I'm pulling in the heat then I see 190*-195*. Seems to be fine for me. <br><br> <br><br>These do work BUT you can raise temps by allowing the coolant to run through the radiator to fast. Not giving the radiator enough time to cool the coolant. This is somtimes seen by removing the thermostat all together in some cases (not refering to our trucks). I still agree with your first comment about higher EGT's make for a hot engine.<br><br>bpk, You said you '02 HO runs hotter than your '98. Thats because the HO's run hotter all the way around than the non HO's. Nobody seems to know why. Maybe the higher compression? Dont know. ???

 

KATOOM, thanks for the info. Like I said maybe I'm making to much of this.

 

I think you have gotten some bad info. I took a 180 stat I had purchased for my 98.5 24 valve and just put it in my 03 SO!! It works great and my temps are down about 10 degrees. I find it hard to believe that the stat housing is different on an HO but...............

 

As stated before, the thermostat allow the engine to heat up faster. If all else is well, the coolant temp will be close to the thermostat rating. A cooler thermostat will not prevent overheating, a common misconception. It can marginally improve the time it takes to overheat, but it ain't much. Also, the higher the engine temp, the more efficient it is (to a point). Also the coolant flowing too fast, like KATOOM said, will actually be less effective. Of of the most overlooked areas when troubleshooting cooling problems is airflow through the radiator, and it's ability to exit the back side of the radiator without turbulence or back-pressure.

 

<br><br>I'm sorry but I dont see where anyone said that the '02 thermostat housing is any different than the '03? And just wondering, are your temps down all the time, even during towing or pulling hills or are they 10* cooler while cruising around driving?

 

KATOOM: You know, I don't know if the guy at Cummins knows what he's talking about or not. If it's like everything else in this town is half B.S. The 02 seems to run about 5 degrees warmer than the 98. It doesn't get hot hot just warm warm. On a long hard pull I'm just trying to keep it cool as long as posible so the motor absorbs as little heat as posible. I've driven truck for 35 years and I know that most of the heating is caused by the right foot. I'm talking about pulling with my trailer.

 

Just go to Cummins and ask for a thermistat for a 99. It will fit and work fine.<br>If you are running hot I bet the radiator has oil on it from the overflow bottle.<br>I put a hose on the breather and moved the overflow bottle the the GARAGE SHELF till it is correctly designed.!!<br>Wash the radiator out to get the oil off of it.

 

If you say you had a 180* stat in your '98 then there's your 5* difference your seeing. Plus I'm sure the gauges arent perfect. But still consider the fact that the HO's do run hotter EGT's and those higher EGT's will effect your coolant temps.

 

I'm trying to reconcile what I'm reading in this thread about 24v HOs running hotter than earlier engines with some of the past threads about cold weather idling. If I remember correctly without searching for those threads, hasn't it been claimed that the 24v engines supposedly lose heat faster when idling? What might be the reason for that, while simultaneously explaining how they &quot;run hotter&quot; as claimed in this thread? I'm not attacking anyone for their statements, just trying to understand what seems like contradictory info...