milleym

Hi all;

I'm in the middle of doing a head gasket repair on my 2.8L V6.

After taking the left head off, I found a broken sensor that screws into the head. I'd obviously like to replace it since I'm down this far, The trouble is, I don't know what sensor it is. It looks like an oxygen sensor, but the Service Manual says that it's further down the exhaust.

Please take a look at the pictures and let me know: a) it's name and b) where it connects to--as you can see, the entire top half of the sensor is missing.

Thanks in advance,

-Mark

91interceptorZ

iTrader: (3)

it's a coolant temp sensor...your car should have one on each head and one on intake..... I believe that on controlls the gauge.

dr.fiero

Just to be on the safe side.... what color wire went to it? Can tell for sure then (though I'm apt to agree with the temp sender).

milleym

Actually, I have no idea. That's the state it was in when I found it; I have yet to search the wire that should have been connected to it. Presumably, the Sensor's tail is still in the connector.

91interceptorZ

iTrader: (3)

it probably will be a single wire to it....does you factory gauge (water temp) work??

milleym

Well, I'm assuming at least one termometer was working; the gauge on the instrument panel happily told me I was overheating prior to the disassembly.

91interceptorZ

iTrader: (3)

was it actually overheating....might have been that sensor malfunctioning.....the wayI understand it is driver's head is gauge....passenger head is electric fan switch...and on intake is for computer......You should be able to replace it easily....just ask parts store for a coolant temp sensor, but take it with you to match it up the best you can....it should again be a one wire....should cost under $20 bucks....I just replaced mine and it looks the same....but do match it cause once I put the passenger side one where the driver's side one goes, and that doesn't work...

milleym

Yes, it was definately overheating.

It actually makes sense that the wire is misisng now; the previous owner had done a bunch of hack jobs on this car, like removing the MAF sensor instead of replacing it. He said he had wired it so the fan would constantly run; apparently he accomplished this by wiring the wire that should have gone to that sensor to another circuit.

Good times....

91interceptorZ

iTrader: (3)

I hate wiring....especially when it's hacked....

Damon

From what you've posted and what you've described, it's the cooling fan temp switch. It's an on/off kind of switch. At a certain temperature the switch closes, which grounds the wire attached to it and that activates the relay for the cooling fan.

So if he rigged it to run all the time he probably just took the wire that went to that sensor and grounded it somewhere. No 12V+ power source required if that's how he rigged it.

91interceptorZ

iTrader: (3)

I get them backwards sometimes...I can never remember which side is fan and which side is gauge...lol

Pete's 89 GTA

iTrader: (1)

back from the dead but anyone know what size hole/thread that hole for the sensor? Is it 16mm?

sofakingdom

iTrader: (1)

3/8" pipe

Pete's 89 GTA

iTrader: (1)

really? tried to put an autometer 3/8" pipe adaptor in the hole seems it wouldnt go in, maybe we didnt have it lined up just straight.

sofakingdom

iTrader: (1)

It's 3/8" pipe

Blee dat

Pete's 89 GTA

iTrader: (1)

thanks will redouble my efforts

sofakingdom

iTrader: (1)

Might want to run the sensor through a die to clean up the threads... and maybe tap out the hole in the head for the same purpose.