That temp sensor on the back of my block seems to be a little too close to my valve cover to get a socket around. A wrench doesn't have any play either once it is around it. Anyone know how such a simple task like this can be completed without removing my whole damn valve cover?

I just wanted to test if my fluctuating temp. gauge was a simple sensor...No such thing as simple I am finding out.

 

Mine just pulls off...

 

My temperature sending unit (at the back driver's side of the block) screws into the block, like the OP.

Maybe you can take out the fuel rail to give yourself some extra room to get a wrench in there. I haven't yet had to replace mine so I'm not sure.

But once you get it out, just throw on a little teflon tape and put it in as tight as your fingers can go so you don't run into this problem again.

 

A crows foot maybe?

http://www.google.com/imgres?um=1&hl...9,r:4,s:0,i:84

 

Yeah, mines a renix...

 

I just did this on two 4.0's recently, on both i was able to get a socket on it. A 1/4 drive socket would be a tad thinner, if you have a set.

 

I know this might be kinda hard but, if you can figure out a way to try and sit ontop of your motor you could put a wrench on it and push down instead of trying to pull.

 

Deep socket, wobbly, extension, - mine came out easy.

 

The deep sockets I have are for my 3/8 drive and are just a tad too thick. The 1/4 I have are not deep so I'll see if I can borrow some tomorrow. I think the sensor in it now is 1/4 inch, and the one I have to replace it has a bigger head so I may have problems getting that to sit right.

I tried sitting on the engine the other day for better leverage but the wrench contacted the firewall on one side and I think all the wiring or the intake manifold stopped it from going the other way.

I will look into locating some of those handy crows feet also!

 

Sure you have the right replacement sensor? Typically the other coolant temp sensor in the thermostat housing had a larger head on it.

 

open ends, crows feet etc will tend to break the sensor off. Use a full 6 point socket!
if it breaks off, you'll have to pull the head.
If the valve cover is in the way, take it off!

 

I've never used anything more than a deepwell socket and never had to remove anything else other than the wire...

 

You guys got me curious enough, I went and checked mine. 90 Renix is AMC I believe. It's 1/2 inch, a normal deep-well fits just fine.

 

The rear one - at the back of the head - operates the gauge.

The front one in the T-stat housing tells the computer to turn the electric fan on.

The rear one is smaller. If the valve cover is in the way it must be on crooked - there should be plenty of room to get the deep socket on.

I broke one - it was stuck tight. It twisted the sensor body, then broke off. Fortunately I was already pulling the head off.

Make sure the socket is on square and all the way on. If the valve cover is in the way, remove it - it's not difficult.

Replacing - the small one comes in 2 "flavors." One for a gauge, the other is just a switch to operate an idiot light. Be sure to get the right one.

 

That's all I've ever done in 25 years on a 4.0.