1989 F-250 7.3 Project

[IDIBRONCO]

I brought the truck up to 239 degrees shut it and I can turn the fan clutch pretty easily with one finger. It doesn’t “spin” but it doesn’t feel great.

Between this and putting a fan shroud back on, I think you'll have the problem whipped. From my understanding, the shroud does make quite a difference in the cooling of the radiator. Especially if it's partially blocked by an intercooler. Not that it's a bad thing, but it does cut down on the air flow through the radiator to an extent.

 

[The_Josh_Bear]

You can drive no shroud and no fan in the PA winter unloaded and it should never overheat... fixing those two issues is great for towing but there has to be something else going down just cruising around unloaded. I did it here in WA and never overheated unless in traffic or towing early June one day, probably 70* ambient. I forgot I had no fan.

 

[hacked89]

You can drive no shroud and no fan in the PA winter unloaded and it should never overheat... fixing those two issues is great for towing but there has to be something else going down just cruising around unloaded. I did it here in WA and never overheated unless in traffic or towing early June one day, probably 70* ambient. I forgot I had no fan.

That’s what I think too, I’ve driven an NA engine of mine no fan 88 degrees outside unloaded and it got hot but didn’t even trip the light. The big variable to me though is that is taking in outside air directly versus going through a turbo and intercooler system.

If it was a bigger problem, I would expect that the truck wouldn’t be able to control its own temperature. It’s odd that it can sit at 202/203 for actual hours. I let it run almost 4 hours yesterday. As soon as it gets some gas it starts overheating.

 

[hacked89]

As I say to others, if you have a ghost that isn’t apparent yet, run it till it comes out. Otherwise it’s not an issue.

Well from my 235 degree run I sprung a leak. Before jumping to head gasket, I’m suspect of that thermostat and housing from earlier in the thread.

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[hacked89]

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I don’t see any issue here but the leak location is very suspicious. Even when I pulled all the accessories off for a better view it wasn’t clear if it was coming from the t stat housing or not.

 

[Nero]

Almost looks like it's coming from the fast idle/timing advance sensor...

 

[hacked89]

Almost looks like it's coming from the fast idle/timing advance sensor...

In the pic, yes but that was from when I pulled the outlet off and it splashed

 

[jwsfarrier]

I know you are running the glow shift gauges. You might want to confirm that those are the correct Temps as the glow shift gauges I originally went with were not reading correctly. I swapped mine to an Isspro,problem solved. Maybe you've already tried this, just wanted to throw it out there in case you hadn't.

 

[Nero]

I'm sort of inclined to agree with this, because under load my glowshift reads 225 quite often, even when it's sub 40 out. Just sucks cause I like how the gauges are laid out.

 

[hacked89]

That would be amusing if the glowshift is that far off. I have a thermal camera I’ll use. From my “feel” it’s atleast ballpark because when it was 239ish I started to get overflow into the bottle and some steam.

I could also tell right at 195 the gauge stops and starts hovering before climbing again and that’s the open temp on the tstat. Was thinking the same as you guys as one of the options

 

[hacked89]

Fixed the leak, it was the tstat housing something up with it. Put a new tstat and all.

There’s alot of air, I’m going to vacuum bleed it. I did a cap less run up, here’s my observations, I don’t think the glowshift is inaccurate, unless it’s not touching the water for some reason haha.

Passenger side head - 213f
Driver side head - 214f
Glowshift in driver head - 213f
Lower radiator hose - 68 degrees
Upper radiator hose - 170 degrees

Going to go eat, and then work on the headliner.

 

[Nero]

I wish there were a way to keep the heads cooler. Maybe I'll put a second gauge in somewhere.

 

[hacked89]

I wish there were a way to keep the heads cooler. Maybe I'll put a second gauge in somewhere.

I have enough gauges but I was thinking it would be interesting to have a gauge in the other head. Right now I replaced the overheat sensor port with a gauge. That means I still have a port open on the passenger head.

 

[hacked89]

It’s definitely making me wonder if I’m getting bad data like you guys mentioned. The fins are cool to the touch, the lower house is cool to the touch, the upper hose is hot/178 degrees thermal. Seems like a working cooling system. Heads are hot though but I never measured them to this degree to know. Gauge matches the heads. The coolant in the heads is suppose to be cooler than the surface which is releasing the heat. Thermodynamics and all that. I’m half joking wondering if the glowshift isn’t in the coolant stream somehow.

 

[The_Josh_Bear]

Fixed the leak, it was the tstat housing something up with it. Put a new tstat and all.

There’s alot of air, I’m going to vacuum bleed it. I did a cap less run up, here’s my observations, I don’t think the glowshift is inaccurate, unless it’s not touching the water for some reason haha.

Passenger side head - 213f
Driver side head - 214f
Glowshift in driver head - 213f
Lower radiator hose - 68 degrees
Upper radiator hose - 170 degrees

Going to go eat, and then work on the headliner.

Clearly your radiator is working like a champ!

I wish there were a way to keep the heads cooler. Maybe I'll put a second gauge in somewhere.

IIRC he did the 6.9 coolant mod, so this engine should be as easy on the heat as it gets. Makes all of this so much more annoying. If it's not a bad gauge it makes me think it's like a piece of towel got into a coolant channel in that head. I'm sure it's something else but dang.

FWIW I have dueling temp gauges on my rig... one in each head. Had a cheap extra one years back so I added it to the passenger side. They read within tolerance of the gauges of each other, 5-10* difference max.