203* Thermostat

[Keith Browning]

Here's something we haven't discussed: I would imagine most of us have seen the Dieselsite ads for the 2003* thermostat to replace the 195* thermostat installed at the factory on 7.3L PSD engines. Apparently Navistar applications use the higher temp stat and Ford uses the lower. So why the difference?

 

Emissions?

 

Application? (F-Series cooling system)

 

I have read a lot of thoughts and opinions along with some silly claims as well, I thought I would see what you fellas think.

[LARRY BRUDZYNSKI]

I may be wrong but the IH is a heavier truck application and the shut downs on their systems use a high temp rating as well as they have different fan clutch engagement temps.

[Bruce Amacker]

Here's something we haven't discussed: I would imagine most of us have seen the Dieselsite ads for the 2003* thermostat to replace the 195* thermostat installed at the factory on 7.3L PSD engines. Apparently Navistar applications use the higher temp stat and Ford uses the lower. So why the difference?

 

Navistar put heavy duty head gaskets in their engines that could withstand 2003° temperatures.

 

Emissions?

 

Application? (F-Series cooling system)

 

I have read a lot of thoughts and opinions along with some silly claims as well, I thought I would see what you fellas think.

I doubt there is an operating difference in a 195/203° stat. My guess is the difference is driven by the marketing department.

 

In the T444E section of ISIS, it states:

 

Two different thermostats available for this engine model. One has a "START-TO-OPEN" temperature of 89°C (192°F) and a "FULL-OPEN" temperature of 104°C (219°F). The other has a "START-TO-OPEN" temperature of 82°C (179°F) and a "FULL-OPEN" temperature of 95°C (203°F).

 

I doubt many of the hotter stats made it into production, as IH derates HP and fuel delivery starting at 214F:

 

Coolant Temperature Compensation - At coolant temperatures greater than 214°F (101°C) full load fuel quantity is reduced by approximately 6% for each degree of temperature (°C), until engine temperature reaches 218° F (103°C) . Above 218° F (103°C) fuel is reduced by 3% for each °C increase in temperature.

 

 

Maybe the hotter stat is for school bus use in cold climates? Buses have a shitload of acreage to warm up, with no insulation. They have huge BTU heaters in the back of the buses with 1" heater hoses feeding them.

I'll ask the parts guy the next time I see him....

 

 

[Keith Browning]

I am really talking about the aftermarket/DieselStop crowd. I have read about this for a couple of years but paid little mind to it. Look at the site DieseSite.com instead of me trying to explain it all.

[Bruce Amacker]

There's so much bullshit in that ad I don't know where to start. First, the testimonial from "Jeff W." is comparing this "wonderful" 203* stat to a BROKEN 195* stat. Gee, I wonder why his heater works and the truck runs better now. It's because he has Shit for brains.

 

Second, quote:

 

Factory equipped 192F/195F thermostat will maintain an operating temperature at approximately 165F-170F.

 

Bullshit.

 

The downfall to this is that the engine -- when our trucks are not under load --never begins to reach its optimal operating temperature.

 

Whaaaat? What have they been smoking? Have they been watching their temp gauges? IDS Datalogger shows them reaching temp idling in the bay. WTF is wrong with these people?

 

The end result of installing the 203F thermostat should be slightly better fuel economy, less smoke, and maybe a few extra "ponies" to go along with it.

 

OMG. If we tell them it will give more HP, they will be sure to buy it. "See this new car wax? It will make your car go FASTER!"

 

Cylinders can seize, freeze plugs can fall out and other normal symptoms of an overheating engine may occur. Worst case is a blown motor and it won't be covered under warranty.

 

Warranty? On a 7.3? When was this written? When did you ever see freeze plugs "fall out" from overheating? I've seen some fucking TOASTED engines, and never a freeze plug "fall out".

 

WARRANTY INFORMATION:

 

90 days on manufacturing defects and workmanship only.

There are no other warranties, written or implied.

 

Yea, 90 days. This is a quality part, man.

 

As with the OEM thermostat requirements, we recommend that you change your thermostat out once per year to insure proper functioning of the unit.

 

I've never seen the OEM recommend changing a stat every year. And, at $36 each you'll keep the company in the black that way. I called IH and they show $26 for the older stat and $30 for the newer stat.

 

 

This is pure bullshit and the reason I rarely visit those types of websites. Maybe Joe Dickhead sucks down that crap and believes it, but not me. It's scary what people will believe.

 

 

[Aaron]

And if you wanted to get pissy about it, too - if your NON Ford approved thermostat cooks the engine....there goes the "warranty" you speak of again

[Brad Clayton]

Oh man that was a classic rant! Bruce you're in rare form today.

[Jim Warman]

Let's crawl back into the WABAK machine.... I think we can forget the zigzag for this trip....

 

Used to be we'd have a "winter" thermostat and a "summer" thermostat. There were very real reasons for these - conditions most of you have never dealt with.... vapour lock - I'll bet many are at least a little able to sound familiar - and percolation. Switching from a (at that time 185F) winter thermostat to a summer thermostat (160F) was a ritual.... along with the twice yearly ignition tune up (points, condenser, plugs, rotor) - a stop gap measure by todays standards, it could be (depending on where you lived) a very necessary maintenance operation.

 

For many years now, the factory has specified ONE thermostat.... If there is a need - either proven or assumed - to change the thermostat to something other than spec, then there is something else afoot. Either the vehicle isn't being used in a manner intended or there is a mechanical concern that should be addressed.

 

But now we get into that "nether" region.... People that alter engine basics.... be it thermostat, fuel curves, ignition curves, whatever.... They don't do this with an eye on tailpipe emissions.....

 

However - as PROFESSIONAL, CERTIFIED technicians, we have become the keepers of the public trust....

 

Shee-it... why do I keep repeating myself... especially when I am preaching to the choir?????

 

Bruce said it.... What more is there to say? If it is written on glossy paper with full colour pics, all we need add is a few testimonials.... Hugh Jorgan in PA says "this is bitchin' man". Mike Hunt agrees. Phil McCrackin agrees. Billy Mays will double your order.....

 

And I didn't even see the ad..... but you guys need to visit the monkey house to see what the "other" world sees.....

[BrunoWilimek]

There's so much bullshit in that ad I don't know where to start. First, the testimonial from "Jeff W." is comparing this "wonderful" 203* stat to a BROKEN 195* stat. Gee, I wonder why his heater works and the truck runs better now. It's because he has Shit for brains.

 

Second, quote:

 

Factory equipped 192F/195F thermostat will maintain an operating temperature at approximately 165F-170F.

 

Bullshit.

 

The downfall to this is that the engine -- when our trucks are not under load --never begins to reach its optimal operating temperature.

 

Whaaaat? What have they been smoking? Have they been watching their temp gauges? IDS Datalogger shows them reaching temp idling in the bay. WTF is wrong with these people?

 

The end result of installing the 203F thermostat should be slightly better fuel economy, less smoke, and maybe a few extra "ponies" to go along with it.

 

OMG. If we tell them it will give more HP, they will be sure to buy it. "See this new car wax? It will make your car go FASTER!"

 

Cylinders can seize, freeze plugs can fall out and other normal symptoms of an overheating engine may occur. Worst case is a blown motor and it won't be covered under warranty.

 

Warranty? On a 7.3? When was this written? When did you ever see freeze plugs "fall out" from overheating? I've seen some fucking TOASTED engines, and never a freeze plug "fall out".

 

WARRANTY INFORMATION:

 

90 days on manufacturing defects and workmanship only.

There are no other warranties, written or implied.

 

Yea, 90 days. This is a quality part, man.

 

As with the OEM thermostat requirements, we recommend that you change your thermostat out once per year to insure proper functioning of the unit.

 

I've never seen the OEM recommend changing a stat every year. And, at $36 each you'll keep the company in the black that way. I called IH and they show $26 for the older stat and $30 for the newer stat.

 

 

This is pure bullshit and the reason I rarely visit those types of websites. Maybe Joe Dickhead sucks down that crap and believes it, but not me. It's scary what people will believe.

 

 

I agree with you 100%, Bruce, especially the part where they claim "slightly better fuel economy, less smoke and 'maybe' a few extra ponies". What B.S. As soon as the engine reaches operating temperature in normal usage, the thermostat is basically almost always fully open, so the few minutes difference in acheiving this full opening is negligible in my eyes, and hardly warrants those frivalous claims that can never be substantiated in the real world.