So far, I’m really enjoying my wagon. Last weekend I replaced the driveshaft center support bearing & bushing, did a basic tune-up, new brake pads and rotated the tires before taking the 40 mile drive home for Xmas. Along the drive, two new issues have developed:

1) The overdrive now only works intermittently. It is the 4 speed manual trans with pushbutton overdrive. I know this is a common problem, but before I start tearing in and replacing components I was hoping to get some advise on where to look first. Sometimes the button works, sometimes it doesn’t. When it does work, OD seems t o engage smoothly and the dash light turns on. It has never failed to disengage by button or shifting out of 4th.


2) I have started hearing an electronic humming sound towards the rear of the car that is noticeable during idle. Its possible that it may have been occurring when I bought the car, but I’m just noticing it now. The idle is smooth and the accelerates with no problem , but I am worried that one of the fuel pumps may be on its way out and I’m gonna wind up stranded somewhere when it does. Do these pumps normally make some audible noise?

1985 DL Wagon, non-turbo, manual trans
Any advise appreciated. Thanks!

 

I would replace the OD relay. That is the usual problem for an intermittent OD. Both FP's usually are noisy. It's when you don't hear the hum that you should start to worry. While you are at it I would replace the FP relay too.

 

The overdrive problem is most likely an issue with the relay as jagtoes suggested. You can try to re-flow the solder joints on the little circuit board inside the relay. Usually that fixes the problem. To get to the relay, simply remove the glove compartment and the relay should be just to the left of where the glove compartment was.

Regarding the humming noise, most likely it is the fuel pump running. I would check to make sure both pumps are working. There is one in the tank and one under the car. The main pump under the car is obviously working otherwise the car wouldn't run. I would check the one in the tank to make sure it is still working. When it fails, the strain increases on the main pump causing it to be noisier. The car may still run fine (it did on both of my cars) for a while. After a while the strain wears out the main pump.

For steps on checking out the in-tank pump, take a look here:

In the Tank - 240 Volvo Tank Pump and Sender

Good luck

 

Thanks, I will check out that relay over the weekend, hopefully thats all it is. That pump writeup was helpful, too. I'll be checking my in-tank pump as well