1998 Dodge Dakota 5.2L

This is the quick and dirty version of what I have been trouble shooting for a week. My engine coolant slowly gains heat as I drive. What temp it stabilizes at depends on ambient temperatures but here are a few data points these data points are all after the “fixes” below:

Ambient 50F, coolant 200F
Ambient 60F, coolant 210F
Ambient 70F, coolant 225F

Things I have tried or replaced:
1) Thermostat, installed new 180 deg. I tested the old and new in hot water and they both open correctly
2) Manual clutch fan was seized so I replaced with a Lincoln Mark 8 electric cooling fan wired on high. Defiantly is pulling more air than mechanical fan
3) Back flush system and block. Did get some sediment out but defiantly not the worst I have seen
4) Added vinegar and water to system ran and let sit for 1 hour to try and dissolve any deposits. Then flushed at least three times probably more but didn’t really count
5) Replaced water pump because didn’t know what else to try.

So did I miss an obvious problem? The radiator is only a year old and worked great last summer. But right now that is the only other thing I can think of. The radiator gets hot I took one sample from the radiator when temp gauge read 210 and coolant from the radiator measured close to what the gauge read so the heat seems to get to the radiator but doesn’t get dissipated.

Also I can explain anything in more detail just ask, didn’t want to write any more of a novel in the first post.

 

Dumb question but did you install the tstat the proper way? A way to check if the rad is plugged up and I have the same issue right now, well not identical but close. To check the rad heat it up to temp. shut the truck off and touch the rad with your hand. it should be the same temp from the top to bottom. Mine right now the top half is warm/hot and the bottom is cold to the touch like nothing even went through there.

I would suggest replacing the tstat as it is probably clogged up now that you back flushed it. It could also be bad too.

But do the test i suggested a report back.

 

Are you PULLING air with the fans into the engine compartment
and not pushing out the grill?

 

I just read these comments this morning. And that is exactly what I thought of last night. I found that there is a 7" section in the middle of the radiator that is plugged. I pulled the radiator and tried to back flush it and everything i could think of, another soak in vinegar. But once installing it again the same section is cold.

I guess I'll buy a new radiator. Unless anyone has an idea of how to unclog it?

Also the fan is pulling air in and new t-stat was not in during the flushes and is still clean i checked.

Thanks