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Transmission oil pre-cooler

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Michael, The opening size is an awesome catch! I have had the 5.9 Cummins for 28 years and never noticed, maybe because I always buy Napa, Lol Here are two pictures of the difference, first one is Gates, second is Napa.
Nick, thanks for posting the images. I had good success with the Napa 180 and I think there is a 20% off sale at Napa this week. Got an email with the promotion!

Michael
 
Sometimes I think too much, lol...Now I wonder if the smaller opening is a bad thing....slower flow equals longer time in the radiator to cool??

Nick
 
I'm puzzled how a t-stat that opens a bit faster would aid in cooling in the long haul. Care to share your theory? I'm thinking that even if you removed it the engine heat would rise to the same point if climbing a long grade if all other variables were the same.
 
Sometimes I think too much, lol...Now I wonder if the smaller opening is a bad thing....slower flow equals longer time in the radiator to cool??

Nick
Hmmm.......good point. My thinking was to replace the original with one of identical size and construction. The Napa was virtually the same and the gasket is higher quality too. Same as original. I think Stant supplies most of Napa thermostats and the gasket looks to be of the same quality as a Felpro I have used in the past.
I myself would prefer more flow through the system, but I have no data or engineering background to back that up!
If you find a 12 valve 180 degree fan clutch that is fully engaged at 190 I think this would be a great combination with a 180 degree thermostat.
Let me know what you decide to do.

Michael
 
I'm puzzled how a t-stat that opens a bit faster would aid in cooling in the long haul. Care to share your theory? I'm thinking that even if you removed it the engine heat would rise to the same point if climbing a long grade if all other variables were the same.
Engine will run cooler with a thermostat that is cycling proplerly than not having a thermostat at all.
 
Engine will run cooler with a thermostat that is cycling proplerly than not having a thermostat at all.

With unimpeded flow the engine would take longer to heat up but the maximum cooling properties of the radiator/fan would not change. So if the engine is at 210, climbing Wolf Creek Pass, how does a 180 degree stat cause an engine to run cooler than no stat or a 190 degree stat?
 
I'm puzzled how a t-stat that opens a bit faster would aid in cooling in the long haul. Care to share your theory? I'm thinking that even if you removed it the engine heat would rise to the same point if climbing a long grade if all other variables were the same.

I am thinking that since it opens sooner, the radiator will heat sooner and then heat the fan clutch sooner. Like you, I don't think it will help on a long pull but for the short ones it will.

I just pulled mine out and it is the small one, so I guess I got it a Car Quest, they have the small ones. So now what? lol
 
I am thinking that since it opens sooner, the radiator will heat sooner and then heat the fan clutch sooner. Like you, I don't think it will help on a long pull but for the short ones it will.

I just pulled mine out and it is the small one, so I guess I got it a Car Quest, they have the small ones. So now what? lol
Is the t stat you pulled a 190?
 
It don't say, but I am sure it is, that's what I always buy. It runs right at 190-195 normal temps.
Maybe try a Napa 180 degree thermostat to start off at the bottom on a long grade cooler. I think it would help to have a fan that engages sooner before the system is saturated ......you might be able to stay around 195 when loaded and pulling a long grade. No experience myself with loads over 20k GCW and I'm typically 15K to 16K. Climbing grades at speeds above 45 mph I don't see temps above 185 without using the Horton. Using the Horton cools engine quickly when pulling at slower speeds and high air temps when needed! I always try to start a long grade as cool possible using the Horton if required.....per advise of "old timer" Cummins engineer years ago when looking into the Horton EC450 fan clutch kit back in 2001. The 180 tstat and Horton has kept it cool with temps as high as 117 and GCW of 15-16k.
Michael
 
If I could limit my loads to 15-16k GCW I wouldn't worry about the stock setup, no matter where I went. The trailer I pulled up Wolf Creek Pass and the mountain north of Phoenix when it was 107 outside weighed over 14k by itself. I was AC off, windows down, max heat to help the radiator before the grade progressed above 3% and was still at 210+ within a mile of the start of the steeper grades. I seriously doubt that if the fan clutch engaged 10 degrees earlier that the result midway up the mountains would be any different.
 
If I could limit my loads to 15-16k GCW I wouldn't worry about the stock setup, no matter where I went. The trailer I pulled up Wolf Creek Pass and the mountain north of Phoenix when it was 107 outside weighed over 14k by itself. I was AC off, windows down, max heat to help the radiator before the grade progressed above 3% and was still at 210+ within a mile of the start of the steeper grades. I seriously doubt that if the fan clutch engaged 10 degrees earlier that the result midway up the mountains would be any different.
Best of success to you and enjoy watching the temperature gauge while climbing long grades in the mountains without A/C!

Michael
 
Best of success to you and enjoy watching the temperature gauge while climbing long grades in the mountains without A/C!

Michael
Now that I have the 4 row, albeit only towing 11,000 pounds (19,000 GCW), I don't have to turn off the AC. That was the point of me reviving this thread.

Thanks for explaining how a lower temp t-stat makes an engine run cooler when under a load on a hot day.
 
Now that I have the 4 row, albeit only towing 11,000 pounds (19,000 GCW), I don't have to turn off the AC. That was the point of me reviving this thread.

Thanks for explaining how a lower temp t-stat makes an engine run cooler when under a load on a hot day.
Whatever Man! Good luck out on the road!

Michael
 
Installed the 180 Napa, it does have a better looking seal and has the larger opening, also a different bypass seal. I hauled a small load on a local 20 mile haul, it is still erratic like they are when new.

0710181048a.jpg
0710181048.jpg


Nick
 
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Installed the 180 Napa, it does have a better looking seal and has the larger opening, also a different bypass seal. I hauled a small load on a local 20 mile haul, it is still erratic like they are when new.

View attachment 107923 View attachment 107924

Nick
Well great Nick. That was FAST! The Napa 180 is a quality part and I have found them to last a long time too. It will be interesting to see how temps run after all the air is out of the system and it "settles in" so to speak. Since you have a new radiator and many new cooling system parts along with current maintenance you may very well benefit from the 180 thermostat. Hope it works well for you in the high Summer temps of AZ. I would kindly suggest keeping an eye out for a good USED or good deal on a NEW 180 degree/12 valve or early 24 valve fan clutch so it would be fully engaged at 190 degrees. Even though the stock fan does not have enough cooling capacity it might help to start cooling earlier along with the 180 degree thermostat cycling earlier too.
Keep us posted.

Michael
 
Now that I have the 4 row, albeit only towing 11,000 pounds (19,000 GCW), I don't have to turn off the AC. That was the point of me reviving this thread.

Thanks for explaining how a lower temp t-stat makes an engine run cooler when under a load on a hot day.
Meant to say THANKS for the aluminum radiator information. Learned a lot and a three or four row core may would work well for my light 15 - 16K GCW if and when my original radiator fails.
Thanks again!

Michael
 
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Installed the 180 Napa, it does have a better looking seal and has the larger opening, also a different bypass seal. I hauled a small load on a local 20 mile haul, it is still erratic like they are when new

Nick, I think you will find out quickly that the only thing the 180 t-stat will give you is a colder truck this winter. Look at it this way. If your radiator and fan can't keep the engine temp at 190 while pulling a load on a hot day how could they possibly keep it at 180? A 190 t-stat has another benefit, better fuel mileage and more power. Not easily measured but there just the same. Trucks with Evans coolant have 210 degree t-stats to take advantage of the heat benefits.
 
Nick, I think you will find out quickly that the only thing the 180 t-stat will give you is a colder truck this winter. Look at it this way. If your radiator and fan can't keep the engine temp at 190 while pulling a load on a hot day how could they possibly keep it at 180? A 190 t-stat has another benefit, better fuel mileage and more power. Not easily measured but there just the same. Trucks with Evans coolant have 210 degree t-stats to take advantage of the heat benefits.

When you are older like me (and you) you sometimes find things that don't make sense, that actually work Lol...and if not, I have spent $23 (includes 20% off) Plus I saved my old one if I need it this winter, kinda like a short sleeve shirt for summer and a long sleeve for winter. If it don't help at all, I will post it.

Michael, the #THM 375180
 
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