7.3 running hot

[vegas39]

Heres my two cents. With the amount of airflow the fan pulls, I feel like more circulation through the radiator wont hurt a bit. I think the thermostat in these is pretty restrictive. I would never run any engine in cool or cold weather without a thermostat but I see no problem with trying it out for summer, especially in my climate. What sucks is the pain it is to get to the thermostat housing. That and my radiator has no petcock.

 

[vegas39]

What do we use to block off the bypass?

 

[Black dawg]

I cant remember for sure? It has been a few years ago, but it seems like I was able to get a pipe plug started into that hole, maybe I tapped it??


I read an article along time ago that said if you have more than a 10 degree drop in coolant temp through the radiator, it isnt flowing fast enough through the radiator.......this is what led me to take the t stat out at that time. I have a thermostat in now, cant remember if i left the bypass restricted or not, but since I went to a manual transmission I have been able to control temps better.

 

[Black dawg]

that hole in a 6.9 block I have torn apart today, is .750....3/4

Napa sells a rubber expandable plug that might fit that. noe6004001

 

[gnathv]

If you can tow in overdrive the torque converter lock helps with water temperature, no slip to heat trans fluid.

 

[franklin2]

One thing I think you need to remember, these trucks tow over their capacity in all types of weather, without overheating. And there are plenty of stock trucks on here that do it everyday. So I think anyone with overheating problems has a fault in their system somewhere, or there is a modification to the engine or the truck that is causing it to overheat.

You usually don't get something for nothing. More power from a turbo and extra fuel, is going to mean more heat is generated, especially using that extra power constantly. I would think you would have heating problems if this is not accounted for in some way.

 

[The_Josh_Bear]

What's the actual temperature when it's overheating?
I'm interested in this thread, lots of good info. I know one thing about turbocharging an IDI, if you have an exhaust leak you're going to run hot and go crazy.

But if no leaks, your story goes along with years and years of IDI owners... 6.9 never runs too hot and the 7.3 tends to overheat.

Along the lines of t-stat talk I've learned to test them in boiling water first thing before I install. Hasn't changed my life yet but you'll find a dud the easy way vs the hard way.
It really opened up my understanding when I boiled an old t-stat with a new one and they both "worked" but the old only opened half as much as the new.
I don't think you have a dud but it's a thought.

 

[vegas39]

What's the actual temperature when it's overheating?
I'm interested in this thread, lots of good info. I know one thing about turbocharging an IDI, if you have an exhaust leak you're going to run hot and go crazy.

But if no leaks, your story goes along with years and years of IDI owners... 6.9 never runs too hot and the 7.3 tends to overheat.

Along the lines of t-stat talk I've learned to test them in boiling water first thing before I install. Hasn't changed my life yet but you'll find a dud the easy way vs the hard way.
It really opened up my understanding when I boiled an old t-stat with a new one and they both "worked" but the old only opened half as much as the new.
I don't think you have a dud but it's a thought.

I really miss my old 6.9. I had just recently replaced the 7.3 in my 89 with a 6.9 out of my other truck with fresh head gaskets and ARP head studs and some A hole plowed into the back of me. That truck never ran hot after I ditched the 7.3 out of it.
When towing last summer, the temp hit 255 just at the top of the grade.
I'm on my second motorcraft thermostat with the same results, so doubt thats it but stranger things have happened.
I still think the stat doesnt move enough water. Really wanting to experiment with that for a couple days.

 

[Clb]

this is towing a 6-7 k 5er...
edit
to blackdawg
Cuz pistons start to melt at around 1200*????

franklin2
My 93 is bone stock, has sub 60k factory, it got hot once going up i5 in Washington (BIG LONG Grade) @8.5* bumping it back to 9.5 fixed it (this was with the pos faccett e pump)wich I attributed to lack of fuel flow as a hindering factor.
and this week in norcal on a modest grade of 80* weather
both times it hit 230*
No failings anywhere to be noted, seems she got pissy @9.5 for the first time this week.... With a holley red, could be the hydraulic advance issue on the ip perhaps...
just adding to the database here guys.
if this junk ever comes apart I'm doing the 6.9 mod!
Brb