203 degree thermostat for powerstroke

[NotMatt]

96 powerstroke 7.3... it needs a new t-stat anyway, the one in there must be stuck open as it never gets more than slightly above "C" even when I drive it for long distances...

http://www.dieselsite.com/dieselsite203thermostat.aspx

Anyone (who's not trying to sell me one) have an opinion on these 203 degree stats I hear talked about vs just getting a 195 degree one from the parts store? They claim Navistar designed the 7.3 to run at this temp but Ford put a 192 or 195 in from the factory.... this one is designed with proper stem length so that the coolant bypass gets blocked when open, it's NOT an old IDI 203 degree stat.

Purported claims include increased fuel mileage and power, better warm-up in the winter, and better heat from the heater... things my truck lacks in all areas (lol).

What say ye oh NWW wise ones?

Oh, and if I ditch the 203 degree idea... here's another comparison... OEM Motorcraft stat or parts store brand (probably Stant)?

 

[ChopTop84]

I have one of the original 203 t-stats when they were first being made to fit the unique ford waterpump, and that said, I dont think I would do it again.

Here is my reasoning...

As much as a diesel likes to be hot, the powerstroke fuel system uses engine oil under high pressure to operate the injectors. Depending on the age of the engine, the clearances have opened up and the high pressure oil pump is getting tired, and HOT OIL flows right thru the system too easily.

My truck's HPOP was weak, and at full temp, it was a gutless, smoky dog. But as long as the engine oil was cold, she was a rockstar! I've since replaced the HPOP with a modified terminator, and now it runs good hot or cold, but still runs slightly better cold.

Me personally, I would stick with the 196 from FoMoCo. We've had bad luck with aftermarket glowplugs, so wouldnt surprise me if the t-stats were the same way.

Since you've got a 96, you probably have green coolant with the SCA additive. That SCA additive makes sand and tears up water pump seals. Get a coolant filter setup on there to pull the sand out. Probably too late to save your current water pump, but might extend its life a little. Assuming you've been checking your SCA additive level ever other oil change that is...

 

[NotMatt]

I have one of the original 203 t-stats when they were first being made to fit the unique ford waterpump, and that said, I dont think I would do it again.

Here is my reasoning...

As much as a diesel likes to be hot, the powerstroke fuel system uses engine oil under high pressure to operate the injectors. Depending on the age of the engine, the clearances have opened up and the high pressure oil pump is getting tired, and HOT OIL flows right thru the system too easily.

My truck's HPOP was weak, and at full temp, it was a gutless, smoky dog. But as long as the engine oil was cold, she was a rockstar! I've since replaced the HPOP with a modified terminator, and now it runs good hot or cold, but still runs slightly better cold.

Me personally, I would stick with the 196 from FoMoCo. We've had bad luck with aftermarket glowplugs, so wouldnt surprise me if the t-stats were the same way.

Since you've got a 96, you probably have green coolant with the SCA additive. That SCA additive makes sand and tears up water pump seals. Get a coolant filter setup on there to pull the sand out. Probably too late to save your current water pump, but might extend its life a little. Assuming you've been checking your SCA additive level ever other oil change that is...

Good info.

I did a little searching around and it seems most people are in agreement that the 203 degree stat isn't really necessary, though it's not really harmful either. One person said during the summer months when towing he heard his all electric fans come on more often. Most say mileage increases were nil, if any.

I think I'll try out the parts store stat... they are fail-safe so if it fails... safely, lol, I'll go get a motorcraft one. The dealer here wants 30 bucks and they have to order it. :haha:

As far as the SCA stuff goes.... poo on that, I flushed and switched to ELC after I bought the truck. I don't like the idea of sand in my cooling system from SCA additives.

 

[NotMatt]

Also, the motorcraft one the Ford dealership wants to sell me is a 192 degree.

 

[zukkev]

My Stat is OEM and still works like a charm at 160K...When I replace mine, whenever the water pump craps out, it will get another OEM...

 

[stealthrunner1]

Good info.

I did a little searching around and it seems most people are in agreement that the 203 degree stat isn't really necessary, though it's not really harmful either. One person said during the summer months when towing he heard his all electric fans come on more often. Most say mileage increases were nil, if any.

I think I'll try out the parts store stat... they are fail-safe so if it fails... safely, lol, I'll go get a motorcraft one. The dealer here wants 30 bucks and they have to order it. :haha:

As far as the SCA stuff goes.... poo on that, I flushed and switched to ELC after I bought the truck. I don't like the idea of sand in my cooling system from SCA additives.

ELC coolant???:eeek:

 

[NotMatt]

ELC coolant???:eeek:

http://www.puredieselpower.com/cata...CN2M14ykgbUCFct7QgodNnAA9w&m1track=googlebase

 

[Drone637]

Mileage change was really a wash for me. But it's hard to tell when you have a camper on top as well as that just eats up your mileage. The 96 temp gauge is pretty inaccurate anyway, I think there is a hack out there to make it read properly.

 

[NotMatt]

Mileage change was really a wash for me. But it's hard to tell when you have a camper on top as well as that just eats up your mileage. The 96 temp gauge is pretty inaccurate anyway, I think there is a hack out there to make it read properly.

Well, as far as the temp gauge being innaccurate, I know that whole deal... however, I could tell the t-stat was stuck open simply by the fact that the gauge never even gets past the C (though it moves a little), when it used to get up into the normal range after driving a while.

I'm waiting on the parts store to get me a new water neck since the old one was about rusted through, should be here tomorrow, then the new 195 degree stat goes in.

 

[ChopTop84]

Do yourself a favor, and put a very thin coat of sealant on the base of that new water pump neck. They are notorious for leaking, as they are very thin and distort easily. I have an aftermarket one thats significantly thicker metal than what the parts store carry. Nice and reusable!

I ditched the green coolant years ago also. I run the Zerex G-05 yellow coolant. I still run a coolant filter tho and change it every couple of years. I've cut them open, and there is crap in them!

 

[NotMatt]

Do yourself a favor, and put a very thin coat of sealant on the base of that new water pump neck. They are notorious for leaking, as they are very thin and distort easily. I have an aftermarket one thats significantly thicker metal than what the parts store carry. Nice and reusable!

I ditched the green coolant years ago also. I run the Zerex G-05 yellow coolant. I still run a coolant filter tho and change it every couple of years. I've cut them open, and there is crap in them!

You happen to have a link to the aftermarket water neck you have? The only ones I can find are the billet ones for 99+ which are shorter and won't work on my truck without changes to the upper hose and/or belt routing. It looks like maybe I could run an upper hose for a super duty with dual alternators (the one that routes over the belt instead of through) and a 99+ water neck, but I'd have to look closer at the hoses to see how they compare.

Good to know on the coolant filtration stuff. I may look into that after I get some other stuff squared away on this truck, a decent kit isn't all that expensive and good peace of mind and insurance for seals and water pump.

 

[ChopTop84]

oh yeah...earlier trucks have the long neck.. I have a 2000, so I got to use the shorter billet style like what dieselsite.com carries (thats where my 203 t-stat come from also).

I did find this however: http://compare.ebay.com/like/150862336785?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

I think its a bit spendy for what it is, but you could always try and plasma cut out your own? Or maybe one of the metal fab guys on here could custom cut one for you if you brought him a template.

Not sure how the ambulance hose would work on an earlier motor. I have an ambulance hose because if I ever lose a belt, I dont want to half to drain half my radiator to change it!

 

[NotMatt]

http://shop.cptrucks.com/ProductDetails.asp?ProductCode=TF-7.3

Yeah, I found a similar setup, see link above. Seems like a reasonable fix. I'll see if the new neck I got leaks or not. If it does, i'll look into something like that... or look at the ambulance hose and billet 99+ neck route. The super duty trucks have a whole different belt routing, so the ambulance hose still might not work on the OBS truck. Surprising I haven't seen anything online about whether it works or not.

 

[NotMatt]

Nevermind, here's a pic of the super duty ambulance hose for dual alternators.... on an OBS truck, the vacuum pump is right in the way.

 

[KP81]

When I had my 2000 the PO installed a 203 when it needed to be replaced I put I stocker in there and I didnt really notice a difference. Not really worth it in my opinion.

And as long as we are talking coolant also, I ran CAT strawberry red coolant and De-mineralized water. Its what we used at work in the CAT diesels and I got it for free but its great stuff, no additives needed and supposedly you dont need to change it until its been in there for 500,000 miles. It would cost almost a bill for enough to do a change and you really have to flush the engine out good because it doesnt mix with any other type of coolant besides other red coolants.

 

[ChopTop84]

with the majority of these new coolants, you really need to flush the system good when making a change. The process to do a powerstroke is multiple flushes with garden hose water, followed by multiple flushes with distilled water, and then finally you can pour in the new coolant.

Accidentally mixing in a different coolant, or adding tap water causes the coolant to shed its anti-cavitation properties, and to create mineral buildup and sand, which over time will eat holes in your cylinder walls, and destroys water pump seals.

Not a huge deal on older over the road trucks that have replaceable cylinder sleeves. HUGE deal on parent bore blocks such as ours if we want to see 500k or more out of the original block.

 

[KP81]

oh yeah thats what i was getting about, dont forget to pull all the drain plugs also a lot of people do not realize all the places you can get the coolant flowing out of to clear the block of old fluid.

 

[NotMatt]

Yep, really important not to mix them. I flushed mine three different times with water, then once with distilled before I put the new coolant in.

In other news, new 195 degree stat is in and truck is back to running with the temp gauge right between O and R in "NORMAL" on the gauge. Also replace both belt idlers and the tensioner, since one was squeeking pretty bad and the tensioner was making a strange slapping noise.

:awesomework:

 

[Stokes]

for what its worth my powerpoke likes its 203 stat. and the only danger to running ELC coolant is the injector cups seals are not supposed to be compatible with the different chemicals in ELC based coolants. that being said there are many running it and seem to be fine. when i went through my coolant system i flushed and filled mine with Fleet charge (SLC pre mixed). with the 203 T stat my gauge sits right smack in the middle of the gauge.