Dear Tom and Ray:
I'm a busy, poor veterinary student with an old, 1989 Volvo 240 DL. I have a wannabe boyfriend/mechanic who likes to tear into things and see what's inside, then put things back together the best he can. I appreciate his efforts very much, but there are times when I hesitate to risk mistakes. I am wondering what you think about an inexperienced home mechanic changing a fuel pre-pump on my car?
The engine light code and physical symptoms all say the pre-pump is bad. I am so poor that I would love to buy a pump on eBay and have this guy put it in for me. However, the Volvo mechanics say pre-pumps are a very tricky business, and even new ones might go bad. Should I listen to them and pay them the big bucks to fix it? Or can I save some money and let my guy try it? What do you think?
TOM: Well, let's look at the upsides and downsides of each approach, Janel. If you go to the Volvo dealer, the upside is that the car will be fixed correctly. And presumably, they'll even guarantee the work for a while.
RAY: And you'll get to drink all the free, lousy coffee you want in their waiting room.
TOM: The downside is that you're going to pay quite a bit for that privilege. You'll pay a markup on the part, and you'll pay in the neighborhood of 100-dollars an hour for labor.
RAY: The advantage of having your mechanically inclined would-be boyfriend do it is that it'll cost you a fraction of that price.
TOM: The downside is that he might leave your car in pieces. Or in a smoldering heap.
RAY: And if he DOES manage to fix it, it may take a restraining order to get rid of him after that.
TOM: But if you think you can handle the interpersonal expectations that may come from this, I'd definitely let the would-be boyfriend try it.
RAY: But first, have him confirm the diagnosis. The most common symptom of a bad pre-pump is that the car doesn't run well when the gas tank is near empty. But since I don't know of any computer code for a bad pre-pump, you want to do a little more diagnostic work before digging in.
TOM: Start by unplugging the power to the main pump. Then turn the ignition key to the "run" position. If the pre-pump is working at all, you should hear it groaning from the back of the car.
RAY: Then, to see if it's actually pumping anything, unplug the fuel line where it goes into the main pump, and see if a steady flow of gasoline comes out. Did I mention he should extinguish any cigars before doing this?
TOM: If no fuel comes out, then the pre-pump is bad and your adventure begins.
RAY: The pre-pump on this car is located inside the fuel tank. If memory serves, it's accessible from above (fortunately, it's been a while since I've had to do one of these). There's a plate on the floor of the trunk that you remove, and that gives you access to the tank so you can reach down and make the swap.
TOM: But rather than just buying a used pre-pump on eBay, I'd get a new Bosch pre-pump, just like the one that's in there. You may find one online for less than the local dealer sells it for. The advantage of using the original pre-pump is that it fits easily, without requiring any "improvisation."
RAY: If you have the right pre-pump, it should snap in there pretty easily. It's not a terribly difficult job. Just be sure to test it before you close everything up.
TOM: Just like you would in veterinary medicine, Janel. Good luck!