E4_Mafia

Hey Jen I just have a quick question maybe some of you have tried this before my 2000 Cherokee is in great shape and I want to keep it that way I've read enough about the zero 331 heads to be scared. I don't like the fact that my electric fan doesn't come on until almost 2:20 is there anyway to either change out the electric fan temperature sensor with one that makes it kick on earlier
Or is their a way to program the computer to kick on the fan a bit early.
Thanks guys!

extrashaky

Don't be scared. Just be educated about them.

That is normal. On the 2000 and 2001 Cherokees, the electric fan doesn't come on until the coolant reaches 221°. Then it stays on until the coolant temperature drops to 217°. Running that hot is not going to make the head crack. Running it up to 250° or 260° probably will. Below that, the 0331 just cracks if it wants to, regardless of what you do with the electric fan.

What you can do is make sure you keep your cooling system in top shape and also make sure your fan clutch is operating the way it should and that you have a fan shroud installed. Even then the 0331 can crack on its own whim. The only way to reduce that risk to near zero is to swap in an aftermarket 0331 with a thicker deck.

E4_Mafia

Alright. You know I have been losing a small amount of coolant over the last two months. It's like .5" on the coolant bottle after every two fill ups. I hope I don't have a crack I feel like I bought a Cherokee with cancer when I found out about this 0331 thing

Blackcherokee290

There is a TSB out for the heat soak where they reprogram the ECU to kick on the aux fan sooner? If your interested I could look for the tsb #. I rewired my fan to a dash switch thru a relay (I overheated and cracked my 0331 head awhile back). The switch is hardly needed sonce the ecu reprogram however.

Just my .02$

Blackcherokee290

Also....OP..if you go the dash switch route, and run into trouble with the CEL light just message me and I'll dig up my diagram for how to get around it.

I also agree with what extrashaky said about the cooling system.

extrashaky

The key thing with the 0331 head is to catch the crack before coolant in your oil damages your bearings. Loss of coolant is one of the things you want to watch for. That's a small amount you described, so it may be nothing, or it may be that you caught it early.

I would suggest sending off an oil sample to Blackstone. It will cost you $28, and they'll send you the sample kit for free if you fill out the form on their website. Then you'll know, and you won't be sitting there with uncertainty gnawing at your gut.

This is what I was saying above about educating yourself. You have to know what to look for and what you need to do if you find it. Engines are lost when people don't understand what's happening or aren't willing to do what's necessary. In my case, I didn't understand what was happening until it was too late. I hate reading where people see the signs and don't take action.

Blackcherokee290

THIS. My radiator had a crack and I was stuck in traffic on the freeway (socal) in the summer. I knew it had a pinhole but that was the day it broke for real. If your loosing coolant that is crazy important to know why.....I was an idiot and let it go. Cost me almost $1k...when you factor in engine damage due the head cracking. Never quite been the same.