7.3 running hot

[vegas39]

Hi all. Been a while since I've posted but have run into an issue that I cant seem to conquer.
My 93 in my sig, has had everything cooling system replaced over the last 4 years but I still cannot haul our travel trailer in hot weather here. I have a newer motorcraft water pump, second motorcraft stat, new hoses, yes the spring is in the lower hose. I'm currently running a spectra radiator from orielys. I've tried a 3 row champion, 4 row champion and this current one and they all cool the same. Once the temp starts climbing, it just keeps climbing. I have a good fan clutch and when I tow, I reach in and manually pop the spring out of its slot so it runs locked constantly and I can hear it screaming down the freeway.
I've owned 4 of these trucks, one being a 6.9 and the 6.9 was the only truck I could tow with without heating issues. Truck doesnt lose any coolant. Dont think I've topped it up in over two years now.
My trailer is a 32 foot bumper pull and it weighs in loaded around 9,000 pounds. Trying to tow with it here when its 110 plus degrees, is absolutely useless. I'm to the point that I cant use this trailer in the summer and its pretty discouraging. Any input or suggestions would be great. Thanks!

 

[Big Bart]

Check your IP timing, I had the exact same issue after putting in injectors. Ran cool till pulling a substantial load. Then would get really hot and stay hot. I set the timing and the problem went away.

 

[vegas39]

I've had the timing all over the place and right now, its at its happiest spot for running and engine temps. temps. I also turned the fuel down to a normal everyday level. Takes the fun out of hot rodding but as you know, cant tow like that.

 

[IDIBRONCO]

My first question would be do you have a larger, auxillary trans cooler? If your transmission isn't being cooled enough, that would pump more heat into your radiator. Next and not as likely to me, do you have an intercooler? If not, you are pushing hotter air into your engine and that have something to do with it. That's what I've got off the top of my head.
The next thing I would say is that if you ever have the heads off, do the 6.9 cooling mod. That's where you remove the plugs in the block and heads to open up the coolant passages that the 6.9's have open. Then you have to use the 6.9 head gaskets which do work on a 7.3 (I am running like that right now with my 7.3). I know that's not an option at this point, but it's something to keep filed away for future reference. I mentioned this since the 6.9 was the only one that didn't run hot while towing in the summer.
An expensive option would be to run 100% Water Wetter instead of regular antifreeze. I wouldn't recommend that unless you win the lottery though. I can't recall any names off the top of my head, but it seems like there's a few coolant additives that help draw heat out of your coolant more efficiently. Those would do the same thing as Water Wetter, but probably don't cost as much.

 

[Big Bart]

So what is your timing at right now?

Do you have a egt guage? Perhaps the fuel is still turned up a little too much?

With a new radiator, water pump, thermostat, coolant, and cap I cannot think of what else could be keeping your cooling system from working.

Some other thoughts -

Add a bigger tranny cooler if yours is small. The trannys can dump a lot of heat in the radiator.

Have you tried running without the fan locked up? Perhaps on the highway it’s using a lot of hp to turn it at high rpms.

 

[gnathv]

I added a powerstroke style bumper to my 93. The cut outs in the bumper moved a lot of air across the bottom portion of the radiator.

 

[vegas39]

My first question would be do you have a larger, auxillary trans cooler? If your transmission isn't being cooled enough, that would pump more heat into your radiator. Next and not as likely to me, do you have an intercooler? If not, you are pushing hotter air into your engine and that have something to do with it. That's what I've got off the top of my head.
The next thing I would say is that if you ever have the heads off, do the 6.9 cooling mod. That's where you remove the plugs in the block and heads to open up the coolant passages that the 6.9's have open. Then you have to use the 6.9 head gaskets which do work on a 7.3 (I am running like that right now with my 7.3). I know that's not an option at this point, but it's something to keep filed away for future reference. I mentioned this since the 6.9 was the only one that didn't run hot while towing in the summer.
An expensive option would be to run 100% Water Wetter instead of regular antifreeze. I wouldn't recommend that unless you win the lottery though. I can't recall any names off the top of my head, but it seems like there's a few coolant additives that help draw heat out of your coolant more efficiently. Those would do the same thing as Water Wetter, but probably don't cost as much.

I have the radiator trans cooler bypassed at the moment and I'm running a large external cooler. Funny how the 6.9 runs so much cooler with the rear cooling ports. I dont know what they were thinking when they changed that design, it really made a hellava difference in cooling.
Before my last truck got totaled several years ago, it had a hypermax turbo and I went out and bought all the hypermax intercooler stuff for it to convert it over. I bought intake hat, plumbing but didnt buy their intercooler, too expensive. I tried to fit the intake hat to my 93 but it doesnt fit with the banks turbo.
Two weeks before my accident, I ordered a frozen boost air/water intercooler and its still sitting in the box in my shed. I've kicked the idea around of fabbing up a setup for this truck but just havent.

 

[vegas39]

So what is your timing at right now?

Do you have a egt guage? Perhaps the fuel is still turned up a little too much?

With a new radiator, water pump, thermostat, coolant, and cap I cannot think of what else could be keeping your cooling system from working.

Some other thoughts -

Add a bigger tranny cooler if yours is small. The trannys can dump a lot of heat in the radiator.

Have you tried running without the fan locked up? Perhaps on the highway it’s using a lot of hp to turn it at high rpms.

Not sure what the timing is right now but I know its more towards the slightly mild end. I tried running more advanced with no difference in towing temps.
I've got the fuel set for the egt gauge to max at 900 on a grade.
I have noticed a huge difference in towing temps between 100 degrees outside temps and 115 outside temps. You wouldnt think 15 degrees could play such havoc but it really does.
I've tried running the fan both ways and honestly, its the same.

 

[vegas39]

Not gonna lie. The company I bought this trailer from, said its towable with a 1/2 ton truck and I was considering buying one to eliminate all this overheating headache but from what I've read lately, most say its too sketchy to use that size truck for such a big trailer.

 

[Booyah45828]

Still have the fan shroud installed? AC condenser and trans cooler clean? No chrome grill inserts or anything else goofy up front?

If you want to, buy a cheap npt coolant temp gauge and screw it into the lower radiator tank. Knowing that temp will tell you if your radiator/fan is or isn't up to the task.

 

[Big Bart]

The challenge with the timing is your magin is 2 degrees. Up to you but I would buy a timing device and set to 8.5 or 9.5 and rule that out. My truck ran fine and cool, added weight and hit the freeway and bam it got hot.

I do get 115 degrees is warm, so it could be something else. But I do not see members in hot places (Ca, Az, No, Tx) or traveling through hot places having issues. Now pulling trailers up a mountain grade in 100 degree’s and second gear, yes folks do suggest they get hot and some pull over to cool down a little.

Also in that temp you would be running your A/C so look to see if your A/C pump is good (Not binding up.) and take some temp readings on your condensor. One of the members Cubey has a van motorhome and he suggests his a/c puts him up to 230 degrees going up mountains with a trailer in tow when his a/c is on. Stays in the 200-210 range if not.

 

[vegas39]

Still have the fan shroud installed? AC condenser and trans cooler clean? No chrome grill inserts or anything else goofy up front?

If you want to, buy a cheap npt coolant temp gauge and screw it into the lower radiator tank. Knowing that temp will tell you if your radiator/fan is or isn't up to the task.

Yes, fan shroud is in place. everything is spotless clean. Nothing blocking the front. factory grill still in place.
I did have a temp gauge in place of the overheat switch, plus I left the factory gauge hooked up also so I could see what factory reads as opposed to real numbers.

 

[vegas39]

The challenge with the timing is your magin is 2 degrees. Up to you but I would buy a timing device and set to 8.5 or 9.5 and rule that out. My truck ran fine and cool, added weight and hit the freeway and bam it got hot.

I do get 115 degrees is warm, so it could be something else. But I do not see members in hot places (Ca, Az, No, Tx) or traveling through hot places having issues. Now pulling trailers up a mountain grade in 100 degree’s and second gear, yes folks do suggest they get hot and some pull over to cool down a little.

Also in that temp you would be running your A/C so look to see if your A/C pump is good (Not binding up.) and take some temp readings on your condensor. One of the members Cubey has a van motorhome and he suggests his a/c puts him up to 230 degrees going up mountains with a trailer in tow when his a/c is on. Stays in the 200-210 range if not.

We have a member here in vegas with a timing meter. Been a few years since I've talked to him. Been fairly spot on between my ear and timing devices within one or two degrees in the past but may have just been luck and not my ocd autism issues lol.
I will definitely check into a/c issues. I do know that we ran the a/c last time, as my wife would have killed me if we didnt! I think in the future for now, I'll be leaving early in the morning with the trailer before it gets hot and travel alone. They can meet me wherever later in the day. Half the stress, is a truckload of miserable people and an overheating truck

 

[Booyah45828]

That's good you have an actual temp gauge. The factory ones aren't known for their accuracy. Like I said, next time I'd get a cheap gauge and screw it in place of the petcock on the lower radiator tank. Then you'll know if the radiator and fan are working good, or if there inadequate.

 

[Big Bart]

Don't get me wrong, not suggesting you drive around with A/C off in 115 degree heat. Just suggesting you check your A/C pump to insure it is free to spin as needed.(Its not like alternator, it will have some resistance, but it should move with medium effort.) Then test and monitor to see if the A/C is putting you over the top. (Putting more strain on the engine creating more coolant heat. Then taking 115 degree air to say 135 degree air behind the condensor and sending that at your radiator.) If a/c is putting you over the top can you turn off on the hills for 3-5 minutes till you crest and come down the otherside.

That does not take into consideration your air cooled tranny cooler and what that is doing to your air headed to the radiator. So a thought is at somepoint look at if your tranny cooler is heating the air to the air conditioner condensor, that is then sending super heated air at your radiator. (Causing a fail.) If you deem so perhaps you can arrange in a better way so it is not double heating the air. Or doing so in a more ideal part of the radiator.

Lastly if you find it is brief times your getting hot (2-3 minutes up a incline) I have found like the misters in the restuarants, doing so for your radiator works really well. Could be simple like a 2 gallon bug sprayer on the front seat and a hose to the nozzle in front of the radiator. It could be a junk yard window wiper system. (Just get one with more than a quart capacity.) It could be more heavy duty like a tank, pump, hose, sprayer, and switch on the dash. You do not want to spray a stream of cool/cold water at hot components. Rather a nice wide mist. It robs the heat off the metal very fast and I have found it seems to also cool the engine compartment. (But does not soak your components with water, think more like humidity.) We did this years ago on a trip, my buddies truck kept getting hot on the grades, we routed his window wiper wash hose with a drip line mister head, it allowed us to keep the truck cool towards the top of the grades and not have to pull over and wait or try to put cold wanter on the radiator and hope we did not create a bigger issue. We did so on a different trip pulling a friends boat trailer but used a bug sprayer from Home Depot. Both cases it was just to make the hills/inclines but would not be effective if your truck over heats on the flats too.