This is probably a very stupid question, but here goes…

My new job requires that I do a lot of city driving, and while that’s not a huge problem right now, it might be later during the summer.

I noticed the other day, when it was about 80 ish out, in stop and go traffic, I was creeping past 210, despite having a 195 thermostat. I do have some rust in my cooling system, and that probably doesn’t help, but i’m worried about when it gets 90-100 in full stop and go traffic in the middle of the city that I might start to overheat.

“Okay, so just upgrade your fan clutch to the heavy duty one from a ZJ”

Well, there’s only one problem with that. I’m concerned that having an even bigger clutch fan with my already slow 2.5 WITH the A/C on in the summer, that it might be unbearable. I am looking into getting more power out of this thing, but for the time being, I need the money to fund this endeavor.

So, I guess my main question is, that if I upgrade my fan to a heavy duty one from a ZJ, would I see a noticeable loss in power?

 

Does your current fan clutch operate properly? In other words, when the engine is all heated up on a warm day sitting in traffic, does the fan speed up and make an obvious roaring sound when you rev the engine a bit? If so, it's working properly, and I wouldn't recommend you "upgrade." Here's an example of what I mean:


Does your electric fan come on when the coolant temp hits 217*F (I think)? Keep in mind, the thermostat is designed to maintain a minimum coolant temperature, and once it's fully open, it's only airflow through the radiator, either from the fan(s) or vehicle speed that sets the maximum temp. Mechanical fans don't pull all that much air at idle, which is why the auxiliary electric fan will cycle on and off as needed to keep the coolant temps under control when idling. When idling after the engine is heatsoaked, the e-fan essentially determines the max coolant temp (assuming it can keep up), and the thermostat determines the minimum coolant temp when driving.

EDIT: Does the 2.5 even have the auxiliary electric fan?

 

Sounds like a good coolant system flush would be in order. As for the Fan clutch, I would at least replace it with a new stock unit.

 

Yeah, that too.

 

Mine is toasted. It spins at max when I start it up in the morning, and it sounds like a school bus already. And no, there is no electric fan for the 2.5. Just one single clutch fan.

I’m looking to get a new radiator since mine is filled with rust and leaking very slowly from the bottom of it, near the lower radiator hose. I’m also going to flush it like crazy, including draining the block as well.

The only reasons right now that I want to upgrade my fan is because mine is stuck on high, and it would provide better cooling. There is always the option to retrofit an electric fan, and I don’t mind doing that.

Tell y’all what. I’ve got a new radiator on the way and i’ll swap that out along with a good flush, and see what that gets me in terms of cooling ability

 

If you're going through all the trouble, just revamp the entire system. If there's rust, your impeller on the water pump is probably questionable, and it won't cost much more to just replace everything. New stat, pump, cap, rad, and hoses. Flush. It's worth it just for peace of mind.

 

This would be my recommendation also. I used to work in a radiator shop back in the day when they had such a thing. I removed countless water pumps that had very little left in the way of vanes. They slowly disintegrate without any telltale symptoms. Then one day you start running hot.

 

First assure system is as good as new, yes inspect pump too, it may have almost no blades left on the impeller, I have seen it on engines with low miles. Failure to maintain fresh coolant can accelerate impeller destruction.

for the clutch, I replaced mine with a grand cherokee clutch, it works fine, tight fit, but I got a six cylinder.

Lets see, Hot climate driving condition, Stop and go driving, i.e. low engine driven fan rpm, little ram air thru radiator, if AC equided, well that is probably on too. oh and it is a under powered motor too so it is working hard.
This is qualified as extreme duty driving. even when cooling system is factory fresh. Thus the addition of an electric fan can be a great idea, after you service the cooling system. Add the electric fan in addition to the engine driven fan.

Also is your fan shroud in place? Shrouds are critical for making the air move thru the radiator drawn by fan.

Yes a clutch that kicks in sooner, full locked at low rpm is what you may want. I dont think it will hurt anything to do grand cherokee clutch assuming it fits on a four cylinder,
So your fan is currently locked all the time? well that will work as good as it gets at low speed stop and go, but at highway speed it will be at full lock, wasting gasoline as engine powers it, when it is not needed cause you got ram air working from the car speed.

does the 4 cylinder have a smaller than the six cylinder radiator? Just wondering.

Of course maybe something else is cause of running hot. Timing or mixture? dragging brake? engine wear? etc...

You really need full inspection and service of cooling system, that alone may make things rignt. but yes a grand cherokee clutch fits on my 1990 Six banger

 

Please flush the system real good before installing new radiator. dont run all the crud through a brand new radiator!

 

And use distilled water, no tap water. You can flush with hose water, but get as much of the water out as possible before you button it up.

 

Everybody is right, if you are going to do the job, do it one and do it right. Flush the block thoroughly, put in all new hoses, radiator, water pump, etc. Flush the heater core good, plenty of crap can stay in there.

Adding an electric fan as a pusher, that you can use with a rocker switch in the cab, may not be a bad idea. They are not terribly expensive.

 

When I worked in the radiator shop we had this air assisted hose that shot high pressure water through the system. You had to hold your mouth right to keep it on the radiator/heater hose when you squeezed the lever. If you didn't it blew water all over the engine compartment and yourself.

But it blew the crap out of the engine and heater core.

The radiators were coming out for a rod out or recore. The good old days, lol.

 

The 2.5 4cyl already has a bigger clutch fan than the XJ 4.0. The 4cyl fan clutch is the same as a standard duty ZJ 4.0 fan clutch.

 

Look!
Your not gonna get any more performance out of your old beat up 2.5L without spending A LOT OF COIN!
Even then if you drop some money on it your not gonna get a dependable, gas sipping power house. It does not work that way.
In fact I will bet good money that if you put a cam in it, and roller rockers (like you asked this forum about) you will then be looking to rebuild the bottom end of it because it is old and probably clapped out!
2.5L's in Cherokees get run hard, because that engine is just barley enough to power it. Mine was too!

The 2.5 is not a performance engine. As you said a while back.......... It is dependable. TRUE THAT!
Remember this thread?? https://www.cherokeeforum.com/f2/why...irrels-263902/

Then there is what you just stated to us here in this thread:
My new job requires that I do a lot of city driving, and while that’s not a huge problem right now, it might be later during the summer.
SO KEEP IT ALL STOCK! INCLUDING THE FAN CLUTCH.
You told us in another thread that you could not afford to have the Jeep down to long as it is your only car. You also said that you did not have very much money to spend on it?

If you keep thinking you'll get performance from roller rockers, aluminum drive shafts, and all this other BS your living in in a fantasy land.
You want performance?
Swap a V8 engine in it. Or better yet buy another car.

I have spent LOTS of money on my 2.5 (now a 2.9-3.0L).
More money than I really ever should have spent. It also took six months to figure out all the things I had to do to it. And as a matter of fact I am still sorting out a few things.

The lil stroker engine of mine is still slow going up hills, and is no faster on the highway. It rocks down low in 4 low for off road, but you said that you would not be doing much of that.

There are two good Screwtube videos down bellow.
Watch them as they can teach you a few things. Not only that, you'll see what the difference between the ZJ fan clutch and the stock 4.0.

And for the love of PETE, all you guys that run a 4.0 Cherokee PLEASE don't confuse the 2.5 and the 4.0. It's apples and oranges.
THEY ARE TWO TOTALLY DIFFERENT THINGS! This guy has a 2.5L.