Thermostat Choices

PABowhunter · Sep 14, 2016

I know there's been some older threads about thermostat choices, but I couldn't find any specifically for guys with heavily modified setups. I know there has always been a disagreement over the benefit or lack there of for the 203° thermostats. What are you guys making 500+ hp running? How much extra cooling is needed for bigger injectors, turbo, hpop, fuel setups?

Swaan · Sep 14, 2016

How much extra cooling??
A lot!!
I have to back out of it on long grades towing in the middle of summer. Im running a 180 thermo.
I wouldnt recommend the 203 for towing.

OBS-Addiction97 · Sep 14, 2016

I ran the 203* and didn't like it. I went to international and got a 191*, it seems fine so far.

PABowhunter · Sep 14, 2016

Swaan said:
How much extra cooling??
A lot!!
I have to back out of it on long grades towing in the middle of summer. Im running a 180 thermo.
I wouldnt recommend the 203 for towing.

What temps are you reaching that you're backing out?

PABowhunter · Sep 14, 2016

OBS-Addiction97 said:
I ran the 203* and didn't like it. I went to international and got a 191*, it seems fine so far.

What didn't you like about it?

Swaan · Sep 14, 2016

PABowhunter said:
What temps are you reaching that you're backing out?

It goes to 215-220 if im pulling hard for a bit.
We have some big grades over here thou. On the longer pulls ill back out of it so it dont go any higher.
It will sit at 215 with the fan on steady all the way to the top. The cooling could be better in thses obs trucks.
I even have the aluminium Mishimoto rad and still not big enough IMHO.
Never a problem with egts just coolant.

PABowhunter · Sep 14, 2016

Gotcha, makes sense with the OBS trucks not cooling as well as the SD's.

I really need to monitor mine with AE the next time I have a trailer hooked to it.

Swaan · Sep 14, 2016

I think the sd trucks have bigger rads. They dont seem to have cooling issues at all.

The Brad · Sep 14, 2016

How are you guys measuring coolant temps? My truck only shows oil temp through the PCM.

Edit: I just remembered the hand shakers have it in place of Trans temp.

Swaan · Sep 14, 2016

Yup you need to plumb in a manual guage on these trucks. I run a manual auto meter water temp . I put the sender in the water jacket in drivers side head.

superpsd · Sep 15, 2016

I run a motorcraft 175° stat. Tempature confirmed with IR thermometer. 176° at coolant outlet. My EOT hovers just over 180°

PsdPullerJr · Sep 15, 2016

superpsd said:
I run a motorcraft 175° stat. Tempature confirmed with IR thermometer. 176° at coolant outlet. My EOT hovers just over 180°

Is this a normally stocked item for a 7.3 or is it from something else? I ran a 203 for several years, normal driving showed 210 on my autometer gauge. Switched earlier this year to a 180 from riff raff, runs about 190 on my gauge. Can't say I've noticed any real difference, but I like the temps being a little cooler.

superpsd · Sep 16, 2016

Not sure what the number is. It was a motorcraft part. Maybe they changed to a 190 stat. If was some years ago I installed it. Tried to search my email for the part number with no luck.

m_j · Sep 16, 2016

Swaan said:
It goes to 215-220 if im pulling hard for a bit.
We have some big grades over here thou. On the longer pulls ill back out of it so it dont go any higher.
It will sit at 215 with the fan on steady all the way to the top. The cooling could be better in thses obs trucks.
I even have the aluminium Mishimoto rad and still not big enough IMHO.
Never a problem with egts just coolant.

that is the hottest spot in the engine and 215 is not very hot. the fans on bigrigs dont even think about coming on until 230

nothing wrong wit choosing to keep it cooler but you are not even nearing the dangerzone at that cylinder head temp

Turbosuzuki · Sep 16, 2016

I ordered the 180 from riff raff, running the stock 195. Down here in Louisiana we have brutal summers. I don't have guages just the stock idiot crap which doesn't tell me much of anything. I don't beat on my truck just utility trailer with couple of atv,s loaded with gear and family is it.
I figure it wouldn't hurt to help it run a little cooler. Another thing my fan will come on in morning when leaving for work but other than that I have had the truck for 5 years now and it's never come on once it's warmed up.

KBMKVIII · Sep 16, 2016

Twin HPOPs here and the 203*.
Oil temps way too high for my liking.
I would go with the 180.

Swaan · Sep 16, 2016

m_j said:
that is the hottest spot in the engine and 215 is not very hot. the fans on bigrigs dont even think about coming on until 230

nothing wrong wit choosing to keep it cooler but you are not even nearing the dangerzone at that cylinder head temp

Yeah i agree its the hottest part of the engine.
I disagree with you on the 230 part thou,
Ive owned and operated a trucking company for the last 25 years and never have i seen fan on temps at 230. The hottest engines i have in my fleet come on at 216, those are 3406E model cats and c15,c-15 accert cats.

I do get a little paranoid thou when temps get up to 220 with no sign of coming down so i just play it safe and back out of it. , good way to crack a head at 230-240 all the time.