4.0 radiator in a 2.9?

[crawlin91]

Id like to mod my cooling system. Mainly to run the engine cooler and for added power. I was thinking about removing the ac compressor and dropping in a bigger radiator and electric fan...which Ive read a little about but dont know if its the right thing to do.
Will a 4.0 radiator bolt in to a 2.9 or at least be a easy swap? Or should I go with something else (bigger better)
Or is it just a waste of my time/$?

 

[engdept]

the 4.0 radiators are bolt in. If you want a larger radiator, get the automatic 4.0 radiator. You will have to use the 2.9 automatic radiator hoses.

On the efan, spen the money and get a SPAL FAN-PWMV2 controller. I also recommend a Taurus efan as when wired up on the high side it pulls about 4500 CFM. As long as you have it wired right, you won't have a problem.

SPAL tech support can give you a wiring diagram for a high current draw fan; which the high side on the Taurus is a high current draw on startup.

 

[holyford86]

the 4.0 automatic radiator isn't much thicker than the 2.9 radiator. you want a radiator out of a first gen explorer (91-94) automatic with air conditioning. if you have a manual transmission with your 2.9 you will need to get a different lower hose. Some say that the 2.9 automatic lower hose works better and some say that the 4.0 hose works better, I used the 2.9 hose and it works ok. Lowering the temperature on your thermostat is a bad idea as the engine is designed to run with a 195* thermostat. Flush your cooling system before you put in your new radiator so you don't fill it up with garbage. If you want cooling system effectiveness stay with the mechanical fan (the 2.9 auto with ac fan is slightly bigger than the manual trans fan) and get a full shroud as well, and make sure that your fan clutch is working properly. An electric fan is alright if you are going through water frequently but a mechanical fan is going to pull way more air through the radiator. If you still feel the need to have an electric fan use a pusher to supplement the mechanical fan.

 

[AllanD]

uhhhhh? Hello?

The 4.0A/T radiator is TWICE as thich as the "HD" 2.9 radiator.

The 4.0 M/T is THE SAME as the 2.9a/t or "HD" radiator.

The M/T 2.9's come wiht a 5/8" thick single core.
The A/T 2.9's usually gor a 1-1/8" single core
as did the M/T 4.0's

The 4.0A/T got a radiator composed of TWO 1-1/8" cores.

Not ALL 2.9 auto's used the same hoses. you must specify an '89-up
because SOME '83-88 rangers came with a radiator with a straight lower neck instead of the neck that is angled down.

Frankly I find it easier to ask for a 91-94 Explorer lower hose, no stupid questions about what engine, what trans, etc, because it's the same hose.

For the UPPER hose you must be a bit creative with your trimming and tensioning to keep it out of the alternator belt.

I find the hose from CarQuest is slightly different from the others and has an extra little jink in it's shape that makes it easier to route it out of contact with the belt.

BTW, a slightly longer alernator belt improves the situation vis-a-vie' hose clearance.
because as the belt gets longer the alternator is canted out and slightly DOWN
lowering the top surface of the belt.

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[holyford86]

I've seen 4.0 auto radiators in rangers that were about the same thickness as the 2.9 auto radiators before. I thought that the 4.0 radiator out of an explorer with an auto trans and air conditioning was the only one that was over 2 inches thick.

 

[2ranger87]

I've seen 4.0 auto radiators in rangers that were about the same thickness as the 2.9 auto radiators before. I thought that the 4.0 radiator out of an explorer with an auto trans and air conditioning was the only one that was over 2 inches thick.

I parted out a '92 Ranger 4.0 auto that had the thick radiator, and the '90 4.0 auto Ranger that I am currently driving also has the "thicker" radiator........

I've only ever seen the 1-1/8 rad in 4.0 manual Rangers and Explorers.

 

[crawlin91]

I'll be looking for a older explorer and more into doing this swap..
Would removing the ac compressor give me more hp?
so if the stock fan works better, why exactly would anyone install a electric fan then?

 

[engdept]

Would removing the ac compressor give me more hp?

No, the only time the compressor takes power to turn it is when the A/C is on.

so if the stock fan works better, why exactly would anyone install a electric fan then?

If you know how to wire it up, an electric fan can be a benefit to any vehicle (DO NOT let Bob Ayres tell you any different, he hasn't got a clue). The main problem with electric fans is people under size them and don't know how to wire them up.

 

[crawlin91]

No, the only time the compressor takes power to turn it is when the A/C is on.


If you know how to wire it up, an electric fan can be a benefit to any vehicle (DO NOT let Bob Ayres tell you any different, he hasn't got a clue). The main problem with electric fans is people under size them and don't know how to wire them up.

undersize? as in buy one(fan) too small? are they better by themselves or in addition to the stock fan setup?
and by wire them up do you mean getting the run times right to keep the engine at the right temp?

 

[MAKG]

They should be fine in addition to the stock fan (though they aren't necessary with a properly functioning cooling system with the oversize 4.0L radiator). As a replacement, despite what engdept says, there aren't any electric fans out there that will pull enough air under all conditions.

You have a MUCH more difficult target near the Front Range than anyone in the eastern Plains does. Folks in Indiana just can't seem to imagine a 12,000 foot pass in 90+ deg very dry heat on an unpaved road at less than 10 MPH. Or a trip up Mt. Evans is easier, but still very challenging on the cooling system. It's only ten times the altitude as Indianapolis....

 

[Bob Ayers]

+1, stay away from e-fans!!!!


Check out this poll from R-F, and you will see the problems people have had with them!!

http://www.ranger-forums.com/forum2/showthread.php?t=69440

 

[2ranger87]

I have run the 4.0 auto rad with the stock mechanical fan in my 2.9 truck, and have never come close to running hot. And I do a lot of hill climbs, both highway driving and slow speed 4x4ing.

As far as i'm concerned, the only place an electric fan should be used on it's own, is in a mud bogger, or something that spends the majority of its time partially submerged........

If I had an auto truck, I wouldn't hesitate to install a "pusher" fan in front of the trans cooler. (as I have done on a couple of my trucks)

 

[crawlin91]

Im going to do the radiator swap, I will get pics up when its in there.

 

[crawlin91]

on a somewhat related note, do I need to replace the thermostat with a 4.0 thermostat?
the stock temp guage in my truck isnt working think its the thermo?

 

[AllanD]

I've seen 4.0 auto radiators in rangers that were about the same thickness as the 2.9 auto radiators before. I thought that the 4.0 radiator out of an explorer with an auto trans and air conditioning was the only one that was over 2 inches thick.

Ever consider that someone needed a radiator and mistakenly got
one from a junkyard out of a 2.9 auto truck?

don't assume that what you've seen is stock.

Anyone looking at my truck and thinking anything was stock would probably have a brain melt.

I'll be looking for a older explorer and more into doing this swap..
Would removing the ac compressor give me more hp?
so if the stock fan works better, why exactly would anyone install a electric fan then?

when the A/C clutch isn't engaged the compressor is nothing more than an expensive, elaborate idler pulley.

Why do people buy electric fans?
Because they believe the advertising hype produced by people who run buisnesses making and selling those fans for a profit.

the first "myth buster" type thing I should say is:
The "power saved" is ONLY actually saved at the engine's
Horsepower peak, an rpm you are only at momentarily on agressive upshifts.

At "Cruising rpm" it takes very little power to turn a mechanical fan. (very little = Trivial)

Where electric fans fall down is when things get REALLY hot..
Like climbing a 7% grade in 110deg heat at 6000ft.

I can buy the arguement of an electric fan as a SUPPLEMENTAL cooling device, but if you look you'll find very few factory
vehicles that depend entirely on an electrical cooling fan
if it was practical to use an engine driven fan



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