Was doing a coolant change on my jeep the other day and decided to flush it. Then I realized that when I put the hose in the radiator, the water would circulate throughout the entire block and out the radiator hose. This is with the jeep off and engine cold. So I pulled the thermostat housing off and there's no thermostat. I put a new 195 degree thermostat in and finished the coolant change. I bought this jeep last year in October and have been driving it on trails and in the field only since then. Have I hurt anything by driving it with no thermostat? Thanks.

 

Probably not. It's an old (but ineffective) trick to take the thermostat out to keep the engine cooler. I didn't have one in my van, but that thing overheated horribly due to the cab over engine design. Haven't heard of it hurting anything though.

 

I would pull a few spark plugs to look for carbon build up from running rich and for any fouling of plugs.

 

alright, good to know, haven't had any cooling problems since I put the new thermostat is so im not sure why the PO took it out. Oh well.

 

I put new spark plugs in a couple weeks ago and ran some sea foam in it before that. Also, PO had O2 sensor wire cut so I put new one in along with new manifold and MAP sensor.

 

Not really. It's not great to run it without one, but you should be okay.

 

Was sitting in Cavs traffic in cleveland last night after leaving the game and my engine temp gauge started going all goofy. dropping down to around 120and then coming back up to 210 and back and forth. I just read that there are two sensors: one in the tstat housing and one at the back of the engine. Could the cause b one of those?

Thanks in advance

 

First, I'm sorry you're in Cleveland. With that said, it's most likely a failure of the Temperature Sending Unit at the back of the head. That's the one that feeds the gauge. The other one sends information to the computer.

 

Lmao I drove in from pittsburgh for the game with friends. not sure the burgh is much better.


Do you have a part number and/or a preferred brand that would be best to install?

 

You're FROM Pittsburgh? Hell, you should've been grateful to see a decent sports team while you could. (I may or may not be from Cleveland)

Quadratec has it listed here:
http://www.quadratec.com/products/55109_04.htm

I'm trying to cross-reference the part number for you cause I can't find it on the Advance or NAPA sites

EDIT: I actually have one here, and the part number is BWD #WT430. For some reason, all the major sites say it isn't compatible with a 4.0L '00 model, but I don't know why.

 

Thank you! From what ive read it seems like a PITA to replace. Should I leave it to a pro or can i get to it with socket set?

Also, my XJ is a 2000. Will the quadratec one work?

 

When you say it was going back and forth, was it just moving fast or slowly rising and slowly falling. Did it go above 210 or below 120?????

 

As far as I know, any of them should work. But I advise waiting for confirmation first, unless you want to be the test subject and risk having to return the $15 part.

The replacement is actually very easy. Aside from it being in an inconvenient location, you shouldn't have any trouble. My best advice is to make sure it's clean before you try to remove it. This will guarantee you're using the correct wrench/socket size, and it will also prevent debris from falling into the hole once the sensor is removed.

 

I suspect you're thinking it may be a thermostat issue, but they almost always fail into the open or closed position. And even it it is the thermostat, I wouldn't expect it to move so drastically on a repeated basis. It's possible, but I think the sending unit is more likely.

 

The speed of the motion was enough to cause me concern for the integrity of my coolant system. did not go above 210 but did get down close to or at 120. It was not slow motion in the case of the engine heating up, but a noticeable drop and then increase

Dropping the heep at the mechanic tonight to get the evap core replaced, so ill have some time for confirmation to come in. thanks again