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jconway 04-11-2010 06:03 PM

02 wrangler x - coolant sensor or not?
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yikes. please help. re: my 02 wrangler x. i thought it was my coolant sensor that was bad but when i bought the part at auto zone it is not the same at all. I took the part out (where the leak was coming from - engine block passenger side, same height as oil filter but further back.) it's got a small threaded brass neck with a hole in the end and a relay plugs into it. what part is this, if not the coolant sensor? ive attached a pic of it below.

thanks for all the help

06jeep 04-11-2010 06:34 PM

DUDE, thats your oil sending unit........
The coolant sending unit should be the neck of your thermostat.........

doclouie 04-11-2010 06:48 PM


jconway 04-12-2010 10:17 AM

Guys, thanks. That's where the water leak was coming from. Can I assume that means the unit is bad? Any tricks as I replace it?

T-BONE N BIXBY 04-12-2010 11:32 AM

Coolant was coming from the OIL sending unit, or up by the thermostat housing?!! Not sure you want coolant coming from the oil sending unit.

jconway 04-12-2010 04:10 PM

t-bone, yes, the coolant/water was leaking out there, nearest we could tell. hell- does that signal something larger?

T-BONE N BIXBY 04-12-2010 04:43 PM

I don't really know, but when I heard the word oil and coolant in the sentence, I kinda got a bad feeling. BUT, I'm no mechanic.
Have you performed an oil change to see if there is coolant in the oil? Is the jeep running ok? No water dripping or pouring out the tailpipe? Just asking in case you have a blown head gasket.
I'm surprised Jerry B. hasn't jumped on this. He may chime in and give you some better insight than me. Whatever he has to say, believe it.

06jeep 04-12-2010 09:44 PM

are you sure the coolant was coming from there or do you have a soft plug leaking, maybe a hose leaking , could be just about anything. Check around that area really good might be coming from something other then the sensor.....

2003wranglerRHD 04-12-2010 11:15 PM

yup coolant and oil are bad mix head gasket or crack in block is what that means

jconway 04-13-2010 09:34 AM

The jeep was running great. temp was cool; oil pressure and level was good. saw water dripping out and it looked to be coming out just where the oil sending unit is located. as 06jeep mentions, i will look for other leaks around the site, but, gosh, it looked like it was coming out right there. As you can tell, Im a knucklehead but trying to learn more.

And, yes, I'm about to send jerry b a blank check in hopes of his giving me the best advice. He is such a huge help always.

06jeep 04-13-2010 11:22 AM

can't learn till ya dig into coolant can br running down your block and making it look like its coming out from the Oil sending unit, move things around on that side I'm sure you'll find its coming from somewhere else......

Jerry Bransford 04-13-2010 12:06 PM

It's too hard to tell what is going on other than, hopefully, your source of water was external and above the oil pressure sender and it only looked to be coming out of the sender itself. Unless your head gasket has blown, the head is cracked, or the engine block is cracked, there is no way for water to get internally to where the oil pressure sender is. From how you say the engine is running, I can't imagine it having one of those three problems.

jconway 04-13-2010 05:27 PM

thanks, jerry and others, for the replies. I will look for the phantom leak that is (probably)throwing water onto that part and surrounding area.

hoping for a hose leak.....

again, guys, thanks.

jconway 04-15-2010 12:02 AM

UPDATE: as you guys suggested, the water leak is coming from somewhere behind the engine block, sort of on the passenger side. The engine does not run hot, and the oil is pure (no froth, evidence of water.) The water seems to be leaking just between engine and firewall (and dripping on oil sending unit) but I can't see a leaking hose. any idea what's back there? AND could it be related to why the heater seems to run cold at idle speed, but warms up when revved or driving?

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