Not really sure yet. +1 MPG maybe?

 

lol...
I just swapped in a 4.10 8.25 29 spline to my 98 5speed and I feeling the same...
Great low end torque but gas mileage I haven't seen a difference...its been about a few weeks....
How are feeling about high hwy speeds? Still not liking it?
I've noticed that I can press the pedal and go past people and not struggle...
Even on some mini climbs

 

The Jeep goes. It just sucks on gas at highway speeds. So I keep it 60 or lower at all times. I saw minimal gas mileage gains, but maybe if I put the stock XJ fan back in instead of the ZJ one, it'll have less engine drag.

 

Seems like it's getting really hard to find conventional Shell Rotella 10W30.

I did my oil change today and used the synthetic blend version of Shell Rotella 10W30 because it was on sale for $19.99 per gallon, which isn't too bad since I typically pay around $17.99 per gallon for conventional.

 

I usually get my Rotella 5W40 off amazon for $45 for 2 gallons. Just adding my 2 cents

 

Battery died this morning just a few days out of warranty... bummer.

I guess it didn't really die as much as it couldn't really handle a load anymore. It wouldn't want to start the Jeep, but was holding 12v just fine and even 14v when the Jeep was actually on. This morning it wouldn't even fire up.

New battery and I'm back on the road again.

I'm going to try bypassing the heater core this weekend because I think the reason my Jeep keeps going over 210 is due to a clogged heater core, which sucks because I just got done replacing it. I suspect clogged heater core because my heat is only lukewarm.

My experiment is to see if the Jeep continues to get this hot even when the heater core is bypassed, and if it isn't, then I know the heater core is bad.

 

Clogged heater core will not cause overheating. The coolant will just not flow though it. It's not like the coolant HAS to go though the core. Early xjs like mine even had a valve to shut off the flow to the heater core when not in heat mode.

 

Try taking the thermostat out completely so the coolant flows though the rad 100% of the time. If you still have a problem then you have a flow rate issue though the engine - either a water pump that's not doing its job, or blocked coolant passages within the block itself.

Have you ever drained and flushed the engine completely by removing the plug in the block?

 

I don't think that the heater core is clogged solid, just the internal flow passages might have shrunken down due to deposit build up, and thus the coolant is having a harder time flowing and it's heating up more because of it. If that's not it, then I might suspect a faulty thermostat that isn't opening properly.

The big thing that I'm noticing is the heat is never hot even when the Jeep is around 217º. It's not cold either, just slightly warm to the touch, but the hoses get so excruciatingly hot to the touch that I can hardly burp the hoses when it's at operating temperature.

I've done many drains and re-fills, but never via a drain plug, always via the bottom hose or the radiator petcock. If it comes to that, I may also have to do that as well.

 

I've opted to leave my heater core alone. The hose didn't fit anyways when I got it today, and dukie, I was considering what you said.

I might try a new thermostat though.

Today I noticed my idler pulley was lopsided in my engine compartment and so I decided to replace that today.

 

I think I saw your picture in a magazine last week.

 

Really? What magazine was it, you got my attention lol

 

I think it was Peterson's 4x4 or something. It was in readers's sumittted section. If u don't recall submitting a picture then probably wasn't u. Lol.

It was a gunmetal pearl XJ with a stinger just like yours, along with similiar LED light bar. It was from Florida too but I forgot the name of the town and the name of the person.

 

Here ya go...

On page 24 of this magazine,

 

Yup, that's me!

But they got a lot of the information wrong. What's a 4.7L V8 stroker? I was talking about the inline 6 stroker. LOL