mattypat

Does anyone know where the temperature sensor is located on a 1990 XJ limited HO? I have air in my cooling system and need to burp it.

Thanks

xjjeepthing

You could jack the front end up, remove the radiator cap and start it. Air will go to the highest point.

COSXJFAN

Hey Thing, he has a Renix, no radiator cap!

What you need to do is find the sensor, it's on the top of the head on the passenger side toward the back. It has one wire coming off of it, I think if you put the rear wheels on ramps or up a hill and let your jeep cool down, you can remove that and fill until coolant comes out of there. BlueXJ is one of the Renix gurus around here, send him a message and he can coach you through what you need to do!! He is a great guy that loves to help!! HTH!!

okcjeeper

By the way a 1990 isn't an HO, it is the older RENIX style 4.0 and I think the 90 XJ has something in the block but I could be wrong.....my 91 has the temp sensor on the thermostat housing and the sender on the back part of the head...the one on the back is what I used to burp mine..

I'd do what xjjeepthing said but the 90's and older are closed systems and do not have radiator caps..so you need to locate the sending sensor and just losen it to let the air out but wait till the jeep is cold then start it and once fluid starts coming out tighten it up...should be burped then..

okcjeeper

Damn COS beat me to my post..but he should know better then I since I don't have a RENIX ...

xjjeepthing

OOPs sorry , missed the year

BlueXJ

COS is exactly right. I passed up your question b/c I thought you wanted to know about A/C and I know very little in that area. Follow what COS suggested and you should be fine. I have done that on numerous occasions. Ramps are the perfect height.
Blue

c-loss

one thing the temp sensor is on the driver side of the head clear at the back not on the passenger side figured id through that in just in case you couldnt find it sitting there.

ColoradoJeepXJ

I have a 90 and the temp sensor is on the rear driver side of the head. I know because I just had to burp mine.

BlueXJ

Yes missread the post that COS put up. The sensor is on the drivers side and is near the back of the head. It is a single wire sensor. Hard to miss.

mattypat

Does anyone have picture of what it looks like? Should I be looking under my Jeep or at the top end? I see a sensor ( think that has 2 wires) toward the middle on the drivers side. the rear is very difficult to see into.

BlueXJ

Look at the bottom of this page listed as "Almost Sensors" and it is circled.
http://www.lunghd.com/Tech_Articles/...iagnostics.htm