My 87 4wd 5-speed has a 2.9. My first personal Ranger, it was a gift, sort of, with a blown engine.
In looking for an engine, I learned that the 2.9s have a very fatal flaw. If you overheat them at all, even once, there is a very high probability the head(s) will crack. So when I went looking for an engine, the updated heads were a must.
My point is, you’re playing with fire saving a little bit on the cooling system, especially if you live in AZ. I lucked out (for $900) and found a rebuilt engine with upgraded heads. A wreck, rebuilt engine had 40k on it.
When I put it in, I also replaced my (leaking) single core radiator with a 2-core all-aluminum radiator, about $135 (eBay), took 30-45 minutes, very easy swap. Popped in easy with no mods, fan shroud dropped right on, no clearance issues. My only “difficulty“ is the lower radiator hose came out at a different angle and I had to get a new, different hose.
@killswitch21 ‘s metal fan idea is an excellent idea for AZ. Or, the electric fans are an easy to install/swap if you can do a little more than change a light bulb. The tech sections here and these guys can walk you through it, and there’s a big selection on eBay with controls for under $100.
Keeping the existing fan, I added one as a pusher on my 1987 Lincoln Towncar (302/5.0) in about 45 minutes a year ago. I wired it through the ignition but kept it separate from the HVAC circuit. I wanted it as a helper/precaution. I’m in Hotlanta, and several times a year I go to Florida. Still not as hot as AZ. I have two in the box for my 1978 Lincoln Mark V (460/7.5). Out of the showroom new they were bad about getting hot in traffic. The nose is so long, I think I can add a pusher in front and a puller in front of the existing fan, but I’m adding one for sure. Again, not through the HVAC circuit, and I may wire one straight to the battery. Once that 460/7.5 gets hot, it’s hard to cool down.
Having swapped one Ranger 2.9, the radiator and E-fan at $200 +/- is very cheap insurance. & you can probably sell the old radiator on Craigslist for $50-70 in one weekend.
One last thought: Ford realized overheating/cracking heads were a problem and upgraded the heads on all 2.9s at some point. You may already have them on a 1990. Again, if you look in the tech sections, you can find the markings to tell you the difference to see if you already have the upgraded heads. The double core is still cheap insurance. Once you go with two, you’ll never be satisfied with a single....
My 2 cents, hope it helps.
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