GeoGuy

My 2000 XJ feels underpowered especially compared to my stock 96 sport. I have had it about a year and am still working out all the kinks. I recently had the engine completely apart to replace the cam shaft but it still feels like it should be running better. I am running 4.10 gears on 33s with a Dana 44 in the front and a 9" in the rear.

I have also completely rebuilt the cooling system and it still runs hot. New radiator, water pump, cooler thermostat and a flex fan to replace the clutch fan.

I know part of my problem is weight. I have steel rims and they add a lot.

Any suggestions on where to look next or what the problem might be?

kyle96xj

28/33 x 4.10 = 3.48 vs stock 3.55 with less weight could be your issue, ideally you'd have 4.56 gears to fully compensate for the 33s size and weight.
Also what temp are you running at that you consider hot.

GeoGuy

It runs at 210 around town but if it idles for very long or if I'm on the trail it overheats and boils over and that is with a 195 thermostat. I am thinking about adding some hood louvers to help cool the compartment.

kyle96xj

Yeah 210 is where it should be running, some hood louvers might help

extrashaky

Edit: Never mind. You have the classic symptoms of a bad fan clutch, but I see you already replaced it.

jaydubz

how many miles? sometimes engines just get worn and tired. You are running the wrong gears for that big of tires and I got steel rims, doesn't feel that under-powered. Tune up recently?

00jeepXJ

+1 on the gears and steel rims advice.
Look into upgrading your fan clutch. I think that it's a 95 or 96 ZJ 4.0 mechanical fan clutch. I replaced mine with the factory zj that I am talking about and it helps a lot. It's a stop gap I won't lie but it helps. You will sound like a semi truck with it's fan running. Hope this helps.

kyle96xj

Won't that contribute even more to the power loss he is dealing with? I suggest a taurus/Volvo fan and relay it cools better and takes load off the engine, a little more work but also more beneficial.

GeoGuy

It has 160,000 miles on it.

GeoGuy

I got rid of the fan clutch and replaced it with a flex fan so it is always running. I am going to start looking into the rims and gears.

00jeepXJ

The gears are the main problem. With an auto trans and that tire size you should be around a 4.56 or 4.88 to be back into the factory curve ( couldn't think of proper term here ). With being 4.10 gears he is essentially lugging the engine and straining the trans. This is what is causing it to feel sluggish.

Jeepin'_Aint_EZ

x2 on this statement

Steel wheels shouldn't make THAT big of a difference to make it feel sluggish. I run 4.56 gears with 35's on steelies with 3/16" rock rings. These bishes are HEAVY! I don't feel like my XJ is sluggish. Seems to get up and go without a problem.

jaydubz

Ya man, its not only about power loss also, those gears are putting strain on engine and transmission, lugging the engine along with a transmission is not good in any car. I would look into a gear swap or go back to smaller tires, or your just gonna be stressing out the powertrain.

kyle96xj

I know gears are the main issue (see my earlier reply) I'm just saying a mechanical fan to electric fan conversion won't hurt whereas a zj clutch will.