Oxygen sensor on 1991 Park Avenue

[klemmy]

I just bought my son a 1991 Park Avenue, 3.8L. On the way home from the dealer the service engine light goes on. The repair shop says it need a new oxygen sensor, $179. I see the sensor itself is only $20. Is this a real tough job on this car or is my repair shop just being a bit greedy?

Any advice would be greatly appreciated.

 

[thejmfc]

They do tend to be hard to get out, but I'd at least try it yourself first, before spending that kind of cash.

I think you only have one sensor on that car, on the exhaust downpipe, just after the rear manifold, near the rear spark plugs and the firewall. It requires either a special socket with a cutout for the wire, or using a wrench on it. I'd go socket, myself. Less chance of rounding something off that way.

Don't use a Bosch sensor, by the way. These engines hate Bosch O2 sensors for some reason. ACDelco is the way to go, whatever the cost difference may be.

Anyway, I'd soak it good with a good penetrating oil (I'm partial to PB Blaster, myself), wait a few minutes, and try your luck at it. Heat might also help (either by running the car for a few minutes, or via torch, but it's a tight spot for a torch).

And hey, if all else fails, the shop can do it. At least you'll know you tried.

 

[Cadillac_AL]

The O2 sensor on my 94 came out easily with no drama whatsoever with an open end wrench. If yours comes out easily it will be the easiest $140 the shop makes all day. If it was really frozen in there, I would think it would still be hard for the wrench to round it off since it is so big. But if the wrench won't do it, and if I had the new one in my hand and it appeared to be the correct one, then I would cut the wires on the old one and try a deep socket on it and it has to come out. Good luck

 

[Pair of PAs]

Changed mine on 93 PA

I changed the sensor on my 93 PA. Came out very easy. In fact, once I broke it loose, I could unscrew it with my fingers.
Thejmfc: By the way, what is it about the Bosch sensor these engines don't like? I put a Bosch one in my car, seems to run fine except for a skip between 1400 and 1700 RPM's. Almost seems like a timing problem, but I suppose it could be the mixture going out of whack. The engine light doesn't come on. Should I try an AC Delco sensor to see if it makes a difference?

 

[thejmfc]

Already replied to a PM on the sensor deal, but just so you all know...

Bosch sensors tend to kill fuel mileage on a 3800, not sure why. I have heard a couple good Bosch stories, but far more bad ones. Also avoid their Platinum spark plugs like the plague.

Timing on these things is non-adjustable, crank trigger type. Can't go bad, one less thing to worry about.

If your mileage is good with your Bosch sensor, I wouldn't mess with it. If it seems suspect though, I wouldn't hesitate to try an ACDelco unit.

 

[klemmy]

Follow up: That was simple. Sensor was $25, tool was $9. Took less than 5 minutes to do.