Bad Radiator?

[MikeInID]

Hello everyone,
This is my first time posting in about six months, but I'm back in the game after purchasing another Ranger (third one so far). I sold my previous one (87 2.3/tk5/2wd) around that time, which was probably a bad idea in retrospect. Just like that one, the 86 I bought about two weeks ago (exactly the same as the 87, with the exception of it being an extended cab) was purchased as a result of my other vehicle (k-jet '80 Volvo) being non-commish for the time being (melted engine wiring harness). This time, though, the brick is getting the boot once fixed (again).
Seeing as how I need the truck to be in decent working order, I'm in the process of getting it up to a respectable, stage 0 state of tune. Among other issues I'm sorting out at the moment, I've been wrestling with the coolant system in an effort to keep it from overheating. After the truck has run for about 20 minutes, the temp gauge slowly creeps through the "NORML" range on the dummy temp gauge and will overheat unless the heater is turned on full blast. With the heater on, temps drop back down to a reasonable level. So far, I have replaced: heater/radiator hoses, water pump, fan clutch and t-stat (192 deg). Everything is buttoned up: there aren't any coolant leaks and I've made sure the system has been "burped" and filled to capacity. However, the issue persists. After running for half an hour to 45 minutes (with heater on full blast) the front of the radiator is cool to the touch over about 95% of it's surface area. The only section radiating any kind of heat is along the very uppermost section near the top bracket. I'm assuming at this point a gnarly-clogged/rotted radiator is the culprit?
Which leads me to my next inquiry: assuming that the radiator is indeed shot (can't think of anything else it could be at this point), is there any way to tell if a junkyard radiator is any good before I yank it from the boneyard? Any 83-97 2.3 truck's radiator should be a drop in replacement, no? I love these trucks and think they are some of the longest lasting, most reliable vehicles on the planet, and would really like to get the cooling system rehabilitated before moving on to other repairs/adjustments that need done. Any advice or recommendations would be greatly appreciated. As a side note, the truck doesn't burn any coolant or oil, and neither appear to be contaminated with the other. I've also been careful to not let it overheat, so I'm hoping the HG is OK for the time being. Thanks again.

 

[scotts90ranger]

just get a radiator from a truck in a wreck (preferably rear ended or rolled so the side tanks aren't cracked) not just sitting there undamaged. If you modify the top hose and get a lower hose from a '86 thunderbird turbocoupe you can use the bigger explorer radiator but it shouldn't be needed for a stock engine

 

[tomw]

If you can get a dental mirror, you may be able to see the tips of the tubes where they protrude into the tank. If they have 'clots' of stuff on them, steer clear. It will look like growths, and it is crystal growth of some sort. I think it is called 'bloom', but may be wrong.
The general rule I've have in my head is: If it overheats at idle it's the water pump, if it overheats going down the highway, it's the radiator.
You need a radiator. There is no way I know of to get rid of the clotting factor. None of the products available at retail will touch them except the new radiator product. Sorry. Prices on radiators have gone up, and likely will continue to do so. If you find a boneyard radiator, they should guarantee it against leakage and being plugged up. If you find one that still has coolant, it might be more likely not to leak[heh.] You can use a DVOM to measure from the coolant to a ground point on the engine or chassis. If you ge many mv, you need new coolant. I want to say over 6, but my brain is too old.
tom

 

[MikeInID]

Thanks for the quick replies. I must say, the people on this site are way more helpful and respectful compared to some of the other "non-domestic" automotive forums I frequent. Regarding boneyard radiators, if I snag one from an auto tranny'd truck (lots of those in the yard for some reason lol) can I just leave the tranny cooler line ports open, or do they need plugged. Also, my radiator essentially has no real "shroud" to speak of. Would it be worth the $10 for a full shroud off an auto/AC-equipped truck, or is it not really needed?

Thanks again for all your help.

 

[scotts90ranger]

the lines can be left open, they're just a loop...

I'm running an explorer fan schroud that isn't anywhere near efficient (my fan is near 4" smaller diameter than that of a 4.0L engine) on my truck with the explorer radiator (almost 3" thick) and have no cooling issues, I wouldn't bother doing anything fancy with the schroud.

 

[tomw]

My 85 came with a clutch fan and no shroud. It also did not have A/C. If you have and use the A/C, especially in traffic, I would vote for a shroud and a thermo fan. If not, you likely don't need it. The thermal clutch fan does help a bit in mileage as it only works when needed and can pull up to 5 hp from what I've read.
Sometimes you can get funny performance with fans and shrouds where the shroud doesn't help cooling, but I would not personally make any claims.
tom

 

[Rogue_Wulff]

Given the cost of a new rad, I'd hate to take a chance on a boneyard unit. These plastic/aluminum rads don't last very long when neglected, and there is little that can be done to reverse the effects of neglect.
Even a new rad can start clogging up internally in very short order if proper cooling system care is not given.

 

[Bryan22]

im with rogue. spend the $120 on a new one and be done with it. As for the shroud, I'd get one from a junk yard, they really do help to isolate where the air is being pulled from. and for 10 bucks i'd say it's definitely worth it.

 

[MikeInID]

Yeah, good call on just getting a new damn radiator. I'm forced to drive it in it's current state (dropping off/picking up son from school) and driving around with the heat on blast is no fun now that it's nice and whatnot.

As an interesting side note, it appears the LF wheel bearing just couldn't take it any more and self-destructed. Just one more item on the ever-growing list...ever heard the myth of Sisyphus?