1. I think I've hit the next guaranteed Volvo failure. Whenever I start the car (cold start), by the time I back out of the driveway and get into the road the fan in the front kicks on. It's never done that before. A few armchair mechanics thought that it might be cause by a sensor (that has something to do with the coolant) is starting to go out. I've read on here about peoples' fans staying on after the car's off and draining the battery. Any thoughts?

and 2. The check engine light came on, took it to the shop, and the mechanic said the rear oxygen sensor is going out. How much should I expect to pay (he quoted around $400) and could the failing sensor hurt my gas mileage?

I've only filled up once since the light came on and it went from 20 MPG to 18.5 MPG without any change in driving habit.

Thanks!

 

The fan will always kick onwith the A/C compressor so it may or may not be the ECT sensor. How is your temperature gauge behaving?

A failing oxygen sensor will hurt your mileage but anytime you have a CEL the system substitutes a guess instead of the actual reading from whichever sensor or condition has triggered the error. Do you know what the code was? A dirty MAF can trigger some of the sensor range codes.

You really should be doing better than 20 MPG anyway unless you are always in stop and go city traffic.

...Lee

 

>he quoted around $400

A direct-fit OEM Bosch rear sensor is $139+ shipping at FCP Groton:

http://www.fcpgroton.com/category-ex...37/by_year/46/

eEuro ver. may be universal-fit type, which I would avoid but call them to see:

http://www.eeuroparts.com/searchresu...7&cat=1015#

IPD seems more expensive than the above two:

http://www.ipdusa.com/Volvo-850/Exha...p-72-170-1332/

Also note, that vacuum leak can trigger O2 sensor code.


JPN

 

Hey now,

You aren't, by chance, running the defrost are you ?

If the coolant temp sensor failed your fan wouldn't come on when needed, after theengine came up to temp, or at any other time for that matter.


[sm=icon_cheers.gif]

 

When my coolant temperature sensor went out, not only did the cooling fan stay on all the time, the car threw two codes and ran like crap.....if it started at all. $25 for a new sensor, ten minutes of time, and all is well.

 

Hey now,

Bummer [].


[sm=icon_cheers.gif]

 

Hi I have a 1988 240gl volvo and the tempature gauge keeps fluctuating. It is running hot sometimes it is fine and then at times it will go up to the red mark. When I start the car it immediately goes to the middle.Does this sound like I have a problem with my thermostat?

 

I'm not the most mechanically minded guy on this forum, but having experienced a check engine light myself a few months ago I can offer this advice.

Have the code read at Advance Auto Parts, Auto Zone, etc. It will be free but watch out for the mechanics who don't know where the OBD-II is on the 850. The last time I had mine read the guy was looking everywhere for it and was skeptical when I told him that it was right behind the gear shifter, but once he found it he was fine.

The code on my car was an O2 sensor. I made an appointment with my mechanic to get it checked out and possibly replaced. On the phone the mechanic told me that it may not even need replaced.

He was right. After resetting the computer it was fine. He told me to come back if it came on again, but he said he didn't think it would. I went and drove 13 miles of freeway to test it (more on the freeway later) and no problems came up. I haven't had any problems since either (knock on wood).

Interestingly the light came on when I exited one of those automatic car washes. I'm wondering if something in the environment there generated a fluke code. I've had fluke ABS lights come on before too--twice in the past year, once in my garage and once after accelerating over a piece of icy snow stuck right in front of where I had to stop for a red light (I went really slowly over it and it seemed to trigger that light). The ABS lights weren't lit the next time I started the car in both cases.

Like another guy on here said you will know if your O2 sensor is really blown if your gas mileage suffers. That is also what a friend of mine who works at a Dodge shop told me. My Dodge friend also told me that I could have reset it myself if I had disconnected the battery for a while (even though I have no idea how to do it and knowing my luck would either break something or shock myself--he said he would help me out if it happened again though).

My question to you--how often do you drive on a freeway (meaning an open road with few stops where you go about 55mph, maybe higher)? My Dodge friend said that if you don't drive on a freeway much that some part (which I forget the name of) won't open up all the way and that it could possibly be behind these faulty readings. I rarely if ever go on a freeway simply because I have no reason to--everything I go to is located near me and I rarely have to ever drive over 50mph. However, I was told to take the car on a freeway every now and then just to open some things up (I did take a 100 mile round trip on a freeway with it not long after it got reset).

I can't help you with the A/C fan question since mine has been broken for at least three years now, which was before I owned the car. However, I have noticed that the fans can be noisy sometimes when you shut them off if you have them on the "4" speed.

 

The 240 has whats called a temp. compensation board. When they go bad it causes the temp guage to go wacky and do things on its own.
Either you can have it replaced or just bypass it on the back of the speedo cluster.