How old is the radiator cap? Honestly, I doubt that it's the problem, but it never hurts to throw a new one on.
As you know, mine doesn't give me any problems at all (my '92 also has an 8274 mounted the same way but with the added restrictions of a CJ grill); however, mine is a multi core (custom built radiator with brass ends) and a 4 banger. Even with a single core and the 6 cylinder, I just don't see the 8274 making "that much" of a difference. I've run these winches on CJ's with single cores and V8's and not had problems. Sure, it's blocking some air, but it shouldn't be enough to cause the problems that you're having.
My initial thought (because it doesn't heat up on trails or in town) was a water pump. Since yours is new, I wonder if you might have either a catalytic converter problem or maybe even a head gasket issue? If you're having a loss of power, I'd lean toward the cat.
I also can't help but remember that your floorboards got hot (crazy hot) while you were pulling the trailer while relocating. This could also be a symptom of a clogged cat (or even a section of crushed pipe) ...of course, the heat could have also caused a head gasket to fail.
I wish I could be more help. I feel like I've just sent you down more rabbit holes. If it were mine doing this, I'd throw a new cap on and check for crushed sections of exhaust pipe. If nothing changed, I'd pull the winch and monitor it. If it goes completely back to normal, I'd get a multi core radiator. If it's still running on the warm side, you know you've got a problem. At that point, I'd probably throw in a new water pump, thermostat (the thermostats with the safety hole seem to fail more often), and radiator (I'm assuming that the water pump and radiator are both under warranty, so you'd just be out the cost of coolant and the thermostat). If it's still acting up, I'd pull the cat and throw a straight pipe (just temporarily for diagnostics) in it's place. Somewhere in the middle of all that, it'd probably be prudent to look for signs of a bad head gasket.
Cooling problems can be a bear to track down. Good luck and keep us posted.
Grant, I actually have a new high flow magna flow cat and I've replaced and welded in a new tailpipe. I also run a Flowmaster after the cat and the cat has a shield on it and the stock heat shield is above the Flowmaster. The waterpump is new as you said and I replaced the head gasket around 200K and got a valve job and resurface done. The thermostat is relatively new and I've been through 4 or 5 radiator caps over the last 14 years. I've gone between 13lb and 16lb. Autozone says to use 13 lbs but I remember my stock cap being 16lbs. I don't think it matters too much but maybe I'll try it. I don't think the M8274 should be a huge game changer given the V8 CJ-5's I've seen run them and never have overheating problems. I've also got a buddy with a Warn Power Plant on the front his YJ with the 4.0L and the only time he had a problem was because he left some cardboard behind the winch by accident. I think he had the stock radiator and mechanical fan.
The bottom line is I think I should be able to run my jeep with any overheating issues regardless of speed.
Holy Crap! When did aluminum radiators get so reasonably priced? I even found a seemingly decent one for the YJ with a Chevy motor at $189. They used to be $600. I'm using a 10 yr old conventional copper construction 3-core vertical flow rad that I already had repaired once for corrosion. I might just swap it out just to get a fresh one.
I keep searching for radiators and I can find all aluminum ones and the standard plastic caps and single aluminum cores all day.
The eBay aluminum ones are 3 core for $175. I can't find brass ones.
The easiest way to get a multiple core copper radiator now is to have one made. I bought my YJ in 1999. By 2003, I'd replaced it once already and it needed another one. Cash was a bit tight and it wasn't leaking (just not flowing well), so I took it in to an old guy who repaired them to have it rodded out. He said he could do it, but for $20 more, he'd rebuild it with caps from a CJ and custom make the core. I honestly don't remember whether it's a three or a four core, but I haven't had to mess with the radiator since (I've had cooling issues, but not because of that radiator).
He died about 5 years ago. It's a shame that all the guys who did specialty repair work on things like radiators, starters/alternators/generators, and the like are retired or have passed away.
Good luck finding one Lou.
Also, you mentioned that the taurus fan doesn't cover the whole radiator... I used one out of a T-Bird (I think) that had a 4.6 in it. It's the same fan that you have, but the shroud fits my radiator like it was made for it.
“The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed.” ― Robert M. Pirsig, Zen And The Art Of Motorcycle Maintenance: An Inquiry Into Values
94 Jeep Wrangler 4.0 with AX-15 Trans.
4" Procomp Lift, 3" body lift, 35" BFG Tires, Ford 9" Rearend with NASCAR Detroit Locker, Super 30 Front with ARB, Onboard Air, Dual Optima Batteries,Warn M8274 Winch, and Bushwacker Fender Flares.
I have a 90 yj with 3 core aluminum and taurus fan. Relocated my winch controls under the hood. I have read about 1 vs 2 vs 3. Apparantly sticking with the stock core (iirc ours is 1) is just fine. When looking at more cores, double check it will fit because it is much thicker than stock. I got mine on ebay and is beef compared to stock. I didnt read all the posts, but try replacing the thermostat either that or the radiator is clogged. Hope you enjoyed Sav- that's my home town.
Louie, What is your coolant to water ratio? Usually you want to have plenty of water in there, especially down south. Do you have at least 50% water? Water can hold about twice as much thermal energy as the coolant can at the same temperature. Water also has about 3 times the thermal conductivity. See the graphs below for details, but in summary, Water can absorb energy in the engine faster than coolant, store more energy than coolant at the same temperature, and dissipate energy in the radiator faster than coolant.
I called the local dealership here to see how much an OEM radiator was. They said $415 and it would be coming from Milwaukee. I believe the construction is similar to what I have now from Autozone based on what the guy said. Plastic ends, single core. He also mentioned the part number changed which I assume means the design changed.