4) Fuel pump notes

4a) No matter how hard I tried on this job, fuel still poured out. That makes it a dangerous job when doing it from the ground without something to pump all the fuel from the tank ahead of time. You have to be careful doing this job if you choose to. For most people, I wouldn't recommend it.

4b) The mercedes benz manual tells you to pinch-off the fuel line coming from the tank. First-off, there's enough pressure coming from all of it that even if you pinch it off with a quality pincher (such as one that Sears sells), you are still going to get fuel out of there (also from fuel left in the system otherwise). Also, once you pinch-off that fuel line, you will probably crack it and cause a leak though I argue most of these cloth-lined 20+ year old hoses are ALREADY leaking-- mine had gas residue on it before I started the job but after I pinched it off, it was more evident. That means this job, for the DIY person, might also include replacing that fuel tank line. For most home mechanics, that will not be possible and so I took the car to my mechanic and for $150 he changed that hose. Expensive for a hose change but he can have it. I was glad to pay him to do that after I changed the fuel pump because I couldn't. He told me that most people, when changing the fuel line, DESTROY THEIR GAS TANK because the bolt from the fuel line hose gets fused and, despite using something to loosen the bolt, go to hard at it and strip the fuel line coupling in the tank. He told me he needed the car for 6 hours and would use PB Catalyst to loosen the bolt and take it out. But he scared me, indicating there were risks. Anyway, I had my car back at the end of the day.

4c) To remove the old fuel pump you need to get those old bolts out of there in the frame. You need PB Catalyst, liquid wrench, wd-40, whatever to loosen those bolts. Be careful not to strip the screw heads. Messing around with this will take you 45 minutes at least and some scraped knockles. You will then want to run-out to the hardware store and get new nuts and bolts, you will not want to re-use the old ones based on my experience.

4d) When removing the high pressure fuel fitting from the pump, you must SUPPORT the pump bolt/housing with another wrench so that the torque from removing the external hose does not destroy the old pump or the new pump when you do the reverse and install it. This is similar to the transmission oil cooler bolt example discussed earlier. Be CAREFUL, do not damage your new pump when tightening down this way, the pump cannot accept your torque.

4e) IMPORTANT, once you pull that old pump off the fuel line, fuel will come pouring out despire your best efforts. IMMEDIAGETELY GRAB THE NEW PUMP AND INSTALL IT ON THE FUEL LINE. The flow of gas will be stopped by the new pump and you will breath a sigh of relief.

4f) Carefully orient the new pump so that the positive and negative connectors (YOU SHOULD MAKE NOTE OF THESE WHEN YOU REMOVE THE OLD PUMP, THE ORIENTATION MATTERS ELSE THE PUMP WILL RUN IN REVERSE!) can easily plug into the new pump. Twist the pump around to get that before you tighten the hose clamp. Put the fuel pump back in the bracket housing, use your new bolts to mount it. Be sure to have the blue plastic stuff on the fuel pump between the pump and the brackets. This prevents corrosion. Tighten down the high pressure line as discussed above.

4g) Wipe the high pressure line with a rag. If it immediately becomes dark again it means you still have a leak there. In my case that meant tightening that hose down further. Once no leaks and everything looks good, proceed.

4h) Push the car without starting it away from the area where any fuel was spilled for safety. Start the car away from that to avoid any sparks. Again, for this kind of reason you really might have a mechanic do this job overall. Anyway, once away, start the car. Use a flashlight and look for leaks. See if the fuel line hose is damp, if so it needs to be replaced (see above). Give the car a drive if all looks good.

5) Temperature sensors

5a) On the theremostat housing are two sensors as mentioned above. One is for the car's dashboard thermostat and the other to turn on/off the aux fan. For about $30 mail order you can get both OEM sensors and simply replace them to remove any variables/guesses in terms of cooling system issues. It's a really easy job to remove them. Drain the radiator, see notes above about fragile connectors, and use the right size long socket wrench to turn it off of there and put a new one on. Easier than changing the oil in the car if you are careful.