Engine/Transmission (1998.5 - 2002) follow up on 180 t-stat

[Cobra]

Back in Feb 2002 Lazy-Boy started a post on the 180 t-stat.

Short Shift and Gray Ghost were going to post the resluts of their test. The original post dried up around august. I didn't see the final results posted by Gray Ghost. Did I miss them? Is there anything more to report? Does the 180 really provide better economy? When I replace my t-stat should I go with the original 190 or get the 180. I expect to replace it this year. Thanks in advance for any info.

 

[TxDieselKid]

I read in a recent post still up near the top, one member said he gained 2mpg by switching over to the 180. Might be worth a try if nothing else.



Andrew

 

[truckstom]

10 degrees cooler = 2 mpg better??



If that's right sign me up... ... Oo.

 

[tntway]

REALLY??????

what's the part #?????????

 

[TxDieselKid]

Originally posted by truckstom

10 degrees cooler = 2 mpg better??



If that's right sign me up... ... Oo.

Like I said, it's what one member posted. Not saying it's true, but that's how I read it.



Andrew

 

[TxDieselKid]

HERE is the link to that post by member Chipstien.



The part number for a 24v is Cummins# 3954194



Hope this helps,

Andrew

 

[Texas Diesel]

I put a 180 in my 2001 HO because a 180 is used in every other application of the ISB ( to the best of my knowledge ). Dodge applications are the only one where a 190F is used, probably because of 0. 0000000001% better fuel ecomony (due to thinner oil) or 0. 00000000000000000000000000000000000000000000000000000000000001% percent lower emissions.



My fuel mileage is a constant 16-18 MPG before and after. I'm happy with the 180. I dont give a rats a$$ about fractional mileage "improvements" or fractional emissions reductions when a 180F t'stat will (I M O ) give longer service life of the engine.

 

[truckstom]

Texas Diesel

thanks for the info.....

 

[dresslered]

I'm not going to suggest that a fuel savings is guaranteed nor have I yet switched my 190 to a 180. However, for my daily use, this might actually prove to be a strong possibility. I commute over a mountain road daily. I have about a 2000 ft. climb/decent each way. What I have noticed is that during my climb I easily reach 190+ as the OEM t-stat would provide. This is approximately the same temperature as when my fan clutch engages (40-80hp wasted). So every day, half way up the mountain, I am running that power robbing fan clutch. I'm thinking that if I was running the engine 10-degrees cooler, I would never engage the fan clutch while running empty. This "could" amount to quit a savings. This might be the real reason that I only see 15mpg out of every tank.

 

[Texas Diesel]

That came out wrong,



The "fractional mileage improvement" statement was in regards to DC going to a 190 instead of a 180 in an effort to squeeze a little more MPG out by thinning the oil more.



I'm sure that what you describe is exactly correct, and others have indicated an improvement in MPG with a 180, I'm not taking issue with that, ONLY the logic behind the 190 being OEM.



Hope this clears up my wording.



Remember in the 1960's, 160F was common, now I've seen some 210F lately , it is higher for emissions and MPG.

 

[WadePatton]

I've been running a 180 for a while now. Can't say as I see a mileage difference. But then I've changed a lot of things. Still getting 18 to 20.



I do like the fan kicking in less often.

 

[MCummings]

One thing about the fan clutch for the auto guys...



Remember,, if your fan clutch never kicks on,, the only cooling your transmission gets is forced induction from the movement of your vehicle.

If I remember correctly some members reported higher transmission temps when switching from 190* to 180* because usually at 190* a small increase in transmission temp could kick the fan on,, with a lower temp T-Stat, it would take alot more heat to turn on the fan clutch.



Just voicing a potential problem,

Merrick Cummings Jr

 

[RustyJC]

Another consideration, especially in Texas, is that, should you get stuck in stop-and-go traffic (read, Houston rush hours) in the summer, less cycling of the fan clutch means less airflow across the A/C condenser coil which equals hot air blowing out of the dash outlets - no fun on a 100+ degF day with 90% humidity. (Been there and done that with my previous V-10!)



Rusty

 

[georgej]

Let's see, the 180 tstat opens earlier and increases the water flow to the radiator which in turn releases the heat into the fan clutch which should make it cycle sooner! It seems to me that a 180 tstat would actually make the fan cycle more often because the engine always generates the same amount of heat for a given chore.

 

[Greg Boardman-RIP]

I live in the So. Cal desert. I have had the 180 t-stat in since last winter. I will tell you that the fan comes on almost as much as before in the summer. If you look at the Guage on our trucks, there is a dot for 180*. I think my truck runs better with the 180*

t-stat in it. Not so much for mileage or HP just better.....

 

[RustyJC]

Originally posted by georgej

Let's see, the 180 tstat opens earlier and increases the water flow to the radiator which in turn releases the heat into the fan clutch which should make it cycle sooner! It seems to me that a 180 tstat would actually make the fan cycle more often because the engine always generates the same amount of heat for a given chore.

The fan clutch engages based on the air temperature it senses. With a 190 degF thermostat, the coolant coming into the radiator when the thermostat opens is hotter than with a 180 degF thermostat; therefore, the average air temperature sensed by the fan clutch is higher with the 190 degF thermostat than with the 180 degF thermostat.



When installing a 180 degF thermostat, one is basically increasing the "dead band" between thermostat opening and fan clutch engagement. It has the same effect as installing a fan clutch that engages 10 degF higher in conjunction with a 190 degF thermostat. This obviously would result in less fan operation, all else being equal.



Rusty

 

[BFC]

Originally posted by MCummings

One thing about the fan clutch for the auto guys...



Remember,, if your fan clutch never kicks on,, the only cooling your transmission gets is forced induction from the movement of your vehicle.

If I remember correctly some members reported higher transmission temps when switching from 190* to 180* because usually at 190* a small increase in transmission temp could kick the fan on,, with a lower temp T-Stat, it would take alot more heat to turn on the fan clutch.



Just voicing a potential problem,

Merrick Cummings Jr

The way I understand it, the only way the stock transmission cooler works is with speed. Unless you have an after market oil transmission cooler the fan clutch won't pull air through it.



Glenn

 

[MCummings]

I'm a stick shift person myself,, I've never looked under the hood of an automatic equipped truck for more than a few seconds,, so, I probably stand Corrected,,



BUT, The truth is I have never been wrong,, I thought I was one time,, but I was just Mistaken. lol J/K



Merrick Cummings Jr

 

[Chipstien]

I have had great luck with the 180 T-Stat....

Went and filled up today so I happened to be logging my milage in my gas log. Thought I would give y'all the before and after MPG's. The six tanks prior to the install of the 180 Stat are as follows... ... ... ... 4/2/02..... 11. 778, 4/8/02..... 14. 201, 4/14/02..... 13. 693, 4/24/02..... 13. 638, 5/9/02..... 14. 188, 5/17/02..... 14. 163. This consisted of 2289. 1 miles and 168. 076 gallons of diesel for a grand total of... ... ... ... ... ... ... ... ... ... ... ... ..... 13. 619 MPG.

As for the next 12 tanks of gas... ... ... ... . 5/25/02..... 15. 54, 6/4/02..... 16. 15, 6/14..... 14. 86, 7/4/02..... 13. 97, 7/18/02..... 15. 7, 7/27/02..... 16. 95, 8/10/02..... 15. 17, 8/23/02..... 14. 85, 9/1/02..... 16. 57, 9/8/02..... 14. 44 (Lost gas from puncture in tank), 9/19/02..... 16. 42, 9/28/02..... 15. 14. I am throwing out the #'s for the 9/8/02 fill-up because I lost around five gallons onto the street and got my truck towed because of it. So the total miles are 5133. 7 and 329. 646 gallons of diesel which computes to... ... ... ... ... ... ... ... ... ... ... ... ..... 15. 573 Miles Per Gallon.

Of course, this would be a difference of..... 1. 954 MPG. Nothing has been added to the truck since 4/2/02 when I had Bill K. do the trans, hence this is why I stopped at that date. And in case your contributing the poor mileage to my foot as a result of the trans mod, think again. I wanted to make sure the transmission was broken in before I got on it so I drove it normal. I probably waste alot more gas now then I did then. So needless to say I am very happy with the results from the 180 Stat but even I have a hard time believing this would be the norm. However for the price of a stat I would give it a try. Now if only there was a way to get this truck into the 18's and 19's in regards to MPG.

 

[Paul Somers]

The only difference I notice with my 180 T-stat is temp. gauge sits just below 190 while towing my 5th wheel in summer with A/C on. It is rock solid. With original 190 T-stat; gauge would go from well below 190 to well over 190 which during winter kept you constantly adjusting heat control.