Guys, I have been bent over by more mechanics than I care to admit. I know very little about the internal combustion engine, and even less about how to work on one when things go wrong.
That said I have a car problem. My daughter drives a 96 Ford Contour, with a V6 engine, and about 75k on the clock. The thing keeps eating Oxygen analyzers/sensors. The mechanic thinks that it needs a new head gasket, for the ungodly sum of about $3000. I know that the car is a real POS, but she apparently has some sort of emotional bond with it. That or she dosen't want to drive my beige Mercury until she is out of college. Low cool points I guess.
I haven't noticed any oil in the coolant, or vice versa. If anyone is in the know and would like to offer advice other than torching this hunk of dung I would greatly appreciate it. I can't see sinking 3K into a car with about a 2K trade in value.  Thanks

How do you know it's really burning out O2 sensors? My truck's check engine light will go on for the O2 and 4x4 sensor will go on for about a week to a month and then just turn off. Funny thing is I don't have a 4x4 and my mpg and acceleration never get affected. I think it's just dust or something on the board. Might be the gas she's putting in there?? O2 sensor might not like how it burns? Not for sure on this, but that's my .02

Might want to make sure the intake is not clogged up.

well at 50 $ a pop for a universal oxygen sensors,  I think I'd just put a new one in again.  3000 clams will buy a lot of them.

Charlie

The wrong kind of silicone sealer (RTV) will contaminate O2 sensors, if you've had any other work done it might be a place to look. The older kind of RTV Silicone would put off alot of fumes and your engine would digest it and it wind up contaminating the O2 sensor.  

A new head gasket for $3,000, are they crazy? Does the car run badly? What are the symptoms? Are the only symptoms the check engine light coming on? I have a 92 Ford Taurus. At 70K miles the check engine light came on, after paying $100 for new one, stayed off for about a week, then Check Engine light kept coming on. it comes on about every 300 miles for a minute or so, sometimes stays on for longer. STILL RUNS FINE. IT NOW HAS 240K MILES ON IT. My advice is to check all the fluids, etc and if it runs fine, JUST DRIVE IT. If the light comes on, put a piece of black tape over it and IGNORE IT.

A blown headgasket doesn't always dump coolant in the oil.  Have another mechanic perform a block test.  This will determine if exhaust gasses are getting into the coolant. "The dye don't lie."

Eddie

Coolant leaking into the cylinders and down into the exhaust will cause oxygen sensors to fail. Have the engine block-tested for carbon monoxide leaking into the coolant. Most shops can perform this service for a nominal fee (my shop charges $19). This is a simple test by which a glass tube filled with a blue fluid is connected to the radiator filler neck via a porous filter. If the blue fluid turns green, you have carbon monoxide leaking past the headgasket into the coolant. I have worked on all manner of cars for well over 20 years now, both foreign and domestic, and the Contour is without doubt one of the worst cars you can own, whether you have the 6 or 4 cylinder version. Have you replaced the water pump yet? Ford used plastic impellers on the early Contour water pumps, which were prone to wringing off the water pump shaft. The car would over heat and you wouldn't know it till you blew a headgasket. You would probably come out better installing a reman engine. Good luck and I hope this helps.
Panzer out
(ASE Certified since 1985)

In some cars there is also a crankcase sensor that is redundant to the O2 sensor, and usually needs changed at the same time.


One other thing. you might visit [url]http://cartalk.cars.com/[/url]
They have a syndicated radio call in/email in question show and will answer anything, and it they don't know the answer they will research it.

Why yes, we replaced the water pump a couple of months ago. I agree the Contour is a real stinker.
Does an average everyday run of the mill mechanic have the ability to test for CO in the coolant?

Napa sells the block test kit. Comes with a glass tube, squeeze ball (to draw fumes through the tube) and a bottle of blue fluid. I don't think it costs more than $20 for the kit, and yes, the average shade-tree can use it.

3K for a head gasket??

WTH with these 4/6cyl cars and their repair prices?

Then again, the only people I've heard of actually changing head gaskets did it on SBC V8s, and did it themselves, so I've never heard a price...

Y'all already know this, but the expense in replacing a $15 head gasket is in the labor of pulling off and replacing the head, etc.  When I stripped out a spark plug in my '86 4Runner, those monkeys wanted $2500 to fix it!!!  ZOWIE!!!  So, I got a gasket kit($59), a reconditioned head($200), and did it myself.  Took a long time, took a little skin off of my hands, but it was fun.  Oh, and FWIW, we used to have a Mystique, the "fancy" Contour, and it had the same issue with the O2 sensor.  That car kinda sucked.

I would get a second estimate. For 3000 you can have a new short block dropped in. Actually you could probably have that done for around 2000. A head gasket change shouldn't run more than 300 a side if even that. Maybe into the 1200's if they have to pull the motor to do it. 300 out, 300 a side, and 300 to put it back in.
You could do it yourself, but get a poloroid camera, or a digital to take pics as you disassemble things. And masking tape to mark all the connections.
I agree also you should use a kit to make sure it is a head gasket.