On the radiator that was in the overheating truck. ...
Ah! The overheating is in my 3.0L to 3.5L conversion. I been running a (huge) new Griffin aluminum radiator in that for the last couple years so I don't know how much help those readings would be. Although, they'd be interesting in a comparison between stock and the Griffin radiator. I have a thermal reader so that's not an issue. Problem is I'd have to tear out the entire radiator assembly, take the fans off and put it all back and I don't have the time right now.
Also, my overheating problem isn't radiator related - its engine timing. The 3.0L ECM has about 2-8 degrees too much timing for the 3.5L engine design. As I've said before, the difference between a Mitsu 3.0L and 3.5L is the same as between a Chevy small block and a Pontiac (not the GM post-'74 "Pontiac" engines, but the real '67-'74 Pontiac engines). You can't run 40 degrees timing in a 3.5L and you sure as hell can't in a Pontiac. The MAX timing in my '03 3.5L Limited is about 34 degrees so that gives you and idea how 'off' the timing is between the ECM and what the engine can take.
I'm still working on the timing map(s) and I'll post it as well as some screen shots here in a bit. There's no question in my case what the overheating is. I'm only modifying fuel delivery and timing. I can disconnect the F/IC and my overheating problem is instantly back (and it runs like crap, relatively speaking); plug the F/IC back in and the engine temperatures are right back down to 192-199 and it runs like a top.
I've been the good boy and flushed my radiators and changed the coolant and did all the things you did, and my core still got clogged up, mostly out of sight of the filler neck. When I did the above test, my outer core areas were dead cold, even tho the tank was a constant temp all the way across. The lack of cooling are led to a chronic overheat under load in warm ambients.
Yea, that'll happen. You have a water problem. I have really hard water at my place. I can't use it for anything; it'd trash a battery or cooling system in pretty short order. That sounds like the problem you're having.
My suggestion is drain and flush the entire cooling system, either get a new, clean radiator or have your existing radiator hot tanked. You're not going to be able to do a good job yourself of getting scale and crud out of a radiator core.
Then use 50/50 pre-mix or buy a few gallons of distilled water from the store mix your own. I'd also suggest a bottle of BG Super Cool or Red Line WaterWetter. BG is cheaper here and that stuff is awesome.
Our radiators are down-flow. I'm not particularly impressed with the design. I've noticed for years that the passenger side of the radiator stays cooler than the driver side where the outlet is. Coolant flow isn't even. That's why I made the primary cooling fan on my electric setup the driver side and the secondary the passenger side fan.
Its possible to design and build a more efficient radiator, but its not worth the money and aggravation. The big Griffin I have is already overkill. Our vehicles don't need that much cooling. If wheeling a 7000 lbs modified Sport in Moab 110 degree weather with the A/C on without going above 199 isn't proof, I don't know what is.
Edward
