Engine Coolant Replacement and Water Pump Hose Clamp Replacement
BravoTwoFour - April 23, 2011
Hey, you don't have to be a mechanic to change out your own coolant, and since it's required to be done every two years, why not do it yourself and save the money? And those factory installed hose clamps are junk - they gotta go... So just have the right tools, parts, time and intention and you can do it!
This procedure was done on my Mp3 500, but it's applicable to many other Piaggio and Vespa scooters as well.
· Agip Permanent Spezial red coolant (same as used by Piaggio OEM with the scooter). I got mine from AF1 Racing (link) This coolant is ready to use and does NOT need to be mixed with water; you'll need to buy two 1 liter bottles.
· Worm-drive hose clamps, preferably stainless steel: two at 1-1/4" and one at 3/4". McMaster-Carr has a full selection of these.
· Paper towels, rags, trash bag.
· Catch basin and/or drain pan; I cut a plastic juice jug to easily fit under the pump.
· A milk or juice jug for taking used coolant to recycling.
· Philips head screwdriver (to remove access panels).
· Pair of good needle nose pliers (to aid in clamp removal).
· Long, thin screwdriver (to help separate hoses from pump).
· 8mm combination wrench (for loosening / tightening coolant bleeder nipple).
· 5/16" and 1/4" hex drivers, or bits (for tightening worm-drive hose clamps).
· MightyVac hand vacuum pump with collection cup and attachments, or suitable alternate.
· A clean funnel
· About four feet of clear 1/8" ID nylon tubing.
· Some twisty-ties or zip ties for holding tubing in place.
· Dremel (or similar) hand tool with cut-off wheel.
· Eye protection.
· Small parts tray.
Preparation and Warnings:
· Read through the coolant replacement section in the Gilera Fuoco maintenance manual starting on page CoolSys-5. Here's a link to the manual: Fuoco Workshop Manual.
· Be extra careful working on the water pump since it is plastic, and plastic is not as strong as you or your tools!
· Coolant can be hazardous, especially to animals and children - be sure to handle carefully, clean up spills, and keep it out of the reach of children.
· Be sure your scooter is cold when starting the work; you'll warm it up later when you bleed air out of the cooling system.
· DON'T OPEN the coolant reservoir when the scooter has just been used and the engine is hot!
· Scooter should be on the centerstand, on a hard surface that can be cleaned (don't work over grass or soil - bad for spilled coolant, and too easy to get dirt on tools and parts).
· You will need to run the engine so if you are working in the garage be sure you can open the door and get plenty of ventilation.
· SAFETY is YOUR RESPONSIBILITY. Work smart!
Some Basic Cooling System Information:
· Reference the Piaggio Workshop Manual page COOL SYS-2 for a diagram.
· Coolant is a special liquid used just as its name implies, to cool the engine. A water pump circulates coolant from the engine to the radiator. An internal thermostatically controlled valve allows the coolant to circulate only in the engine until it is hot enough to require cooling in the radiator, and then opens to all flow to the radiator. When the temperature outdoors is high and/or the scooter is not moving enough to get airflow through the radiator and transfer heat from the coolant to the air, an electric fan is turned on to force airflow through the radiator. A small reservoir for the coolant, that allows expansion and contraction as the coolant heats up and provides a place to top off the coolant, is located under the left side of the dash (accessed by removing a Philips head screw and the access cover panel).
· The Mp3 500 has a water pump for the coolant on the right side of the engine (round black plastic device with three rubber hoses clamped to it; see pic below). The radiator is in front of the front wheels, behind a grille, and the electric fan is behind the radiator.
The Water Pump and Hoses
· On the upper front of the engine is a small bleed nipple used to bleed air out of the engine block high point after a coolant change - and this is very important to do.
- The bleed nipple is accessed by removing the Philips head screw and the access cover panel on the left side of the scooter, just over the pillion left foot rest (see pic below).
The Left Side Access Cover Plate
The Bleed Nipple (arrow)
- The bleed nipple has a small rubber boot on it to keep dirt out; the boot is removed by simply pulling it off. Be sure to reinstall it when done.
- The bleed nipple is essentially a small bolt that is drilled out and is screwed into a threaded hole on the engine that has an off-center drilled hole in it so when the nipple is tightened, the holes are capped, but when the nipple is loosened, the holes can line up to allow coolant and/or air to pass.
OK, let's get started already!
First we drain the coolant and replace the clamps.
Pictures follow the text in several steps.
1. Gather all your tools and materials in one place (preferably where your scooter is...).
2. Put your safety eye protection on. Wear gloves if you want them (but be aware some of the parts are small).
3. Remove the left side engine access cover plate and screw and set them in the parts tray.
4. Wipe off the coolant bleed nipple area on the top front of the engine to remove dirt and debris.
5. Remove the bleed nipple rubber boot and place it in the parts tray.
6. Remove the coolant reservoir access cover plate and screw and set them in the parts tray.
Coolant Reservoir Access Cover Plate
7. Place a catch basin under the water pump area of the scooter to catch draining coolant. Use additional catch jugs and plenty of paper towels to keep coolant from getting everywhere...
Catch Basin and Modified Juice Jug
8. Remove the coolant reservoir cap and place it in the parts tray, open side down over a piece of paper towel (to keep it clean).
Coolant Reservoir and Cap
9. Using the Dremel and cut-off wheel, CAREFULLY cut through the middle of the saddle-shaped depression on the biggest, LOWEST (outer) hose clamp; the cut-off wheel should be held perpendicular to the clamp. Do not let the cut-off wheel 'roll off' of the clamp. When you have cut through the clamp it will pop open. Wipe off the water pump, hoses and engine to get the metal filings out of the work area.
Lower Hose Clamp Cut and Ready to Remove
10. Using the pliers, carefully remove the cut clamp by separating the cut side apart from themselves and then remove the entire clamp. You may start to see a little coolant leaking from the hose at this time.
11. Using your hand, attempt to gently twist the hose on the water pump and see if it will work loose enough to turn. Push the thin screwdriver up into the area between the hose and pump WITHOUT FORCING (don't scar or cut into the plastic) and very gently separate the hose from the pump - coolant will run out, so be prepared.
12. Allow the coolant to drain along the screwdriver and into your catch basin.
13. Once the coolant flow slows down, remove the screwdriver.
14. Now gently twist the lowest hose (the one that was draining) until you can remove it from the pump and push it downward; coolant that is remaining in the hose will drain out. By hand squeezing the radiator hoses at the front of the scooter you will get a little more coolant to drain. Also remove the smaller hose from the pump and push it down so coolant remaining in it is drained.
Lower Hose Off Of Pump
15. Using the Dremel and cut-off wheel again, cut the other two hose clamps on the water pump and remove them. Again, wipe the small metal bits from the grinding off of the area around the water pump. Pull the small hose off of the pump and push it downward as shown below to drain.
Cutting the Remaining Hose Clamps
Draining Small Hose
16. Using the MightyVac (or similar), place the suction line in the lowest part of the water pump and apply vacuum to remove as much remaining coolant as possible. I also had tried vacuuming coolant out of the other areas of the pump but they were already drained .
17. Place the MightyVac aside for later cleaning and wipe down the hoses and water pump.
18. Now reinstall the lower hose on the water pump, ensuring the notch in the hose lines up with the tab on the pump, and the hoses are all fully installed over the pump outlets.
19. Using the nut drivers, turn the screws on the worm-drive hose clamps out (counterclockwise) until the clamp opens. Spread the band of the clamp out gently without straightening it - just enough so the clamp will fit over the hose.
New Hose Clamps
20. Install the appropriate clamp over each hose and work it into position, reinserting the band into clamp, and tightening the worm-drive screw to hold it.
21. Position the band of each clamp evenly about 1/8" back from the end of the respective hose, and tighten each clamp until the band is evenly seated around the hose (do not tighten until hose rubber is being cut by the notches in the band!).
Installing New Hose Clamps
22. Thoroughly wipe off the pump and hoses and areas where coolant may have spilled so you can look for leaks later.
23. Get up off of the floor and stretch! Now wash your hands and go get yourself a glass of water...
Now we'll put the fresh coolant in and bleed the system (this is the fun part!).
24. Using the closed end of the 8mm wrench, gently loosen the bleed nipple from the engine, just so it is free to move - do not remove it. Snug the bleed nipple back up to the engine.
25. Place the clear nylon tubing on the bleed nipple so it is tight in place and secure the tube to the scooter with a twisty tie or such so the tub is held up. Note: Piaggio's manual says to use "transparent" tubing - I looked for this but could not find it anywhere (REALLY hard to see), so clear tubing will have to suffice
Clear Tubing on Bleed Nipple
26. Route the opposite end of the clear nylon tubing up to the coolant reservoir and insert it well into the neck of the reservoir. Use a twisty tie or similar to tie the tubing to the brake lever or line to hold the tubing in place. Note that it's best that the tubing be as direct as possible, with very little dip or drop in it from the bleed nipple to the reservoir.
Clear Tubing at Coolant Reservoir
27. Using the open end of the 8mm wrench, open the bleed nipple about one-half turn. Place a paper towel under the bleed nipple in case any coolant runs out of the nipple threads during filling.
28. Open one of the bottles of red coolant (which is named "Permanent", but must be changed every two years... hmmm...)
Agip Permanent Spezial Red Coolant (and cookie monster...)
29. Place the funnel in the coolant reservoir and start slowly pouring fresh coolant in. Take your time and check that the coolant is not backing up in the reservoir. As the coolant fills the system you will hear some gurgling noises as air is pushed out; however, some air stays trapped inside until the thermostat valve opens, and that only happens when the engine is warmed up.
30. When the coolant is backing up in the reservoir stop filling it. Again squeezing the radiator hoses a bit will 'burp' some of the air out and allow the coolant to further fill the system.
31. Now with the clear hose in place as described above, tighten (close) the bleed nipple. Open your garage door if not outside (be sure you have full ventilation to run your engine!), and start the scooter. As the engine warms up check the water pump hose clamps for any signs of leakage; tighten the clamps if needed.
32. Watch the temperature gauge on the dash. As it begins to come up, loosen the bleed nipple and open it half a turn or more. You will start to see coolant and air exiting and working its way to the reservoir. This is the whole idea, that as the engine heats up and the thermostat opens, the air that is trapped will be expelled; the coolant that is expelled with it is recaptured in the reservoir.
33. While you are bleeding the air out of the cooling system in this fashion be sure the coolant level in the reservoir does not drop below the bottom of the filler neck (you should be able to see the top of the coolant level). Add coolant as needed, sparingly; it will fill very quickly.
34. Once the engine is hot you will continue to see the air and coolant coming through the tubing to the reservoir. BEWARE the coolant is HOT and the tubing will soften a bit. Just keep watch on this and the bubbles will subside. You can tighten and loosed the bleed nipple a few times to let the remaining air gather and expel as well. You may need to replace the paper towel under the bleed nipple if it soaks up a lot of excess coolant escaping the tubing - again be careful, it's hot!
35. Eventually the radiator fan will come on and run for a minute or so, and this means the engine is as hot as it is going to get. Let the engine run long anough for the fan to come on a second time, tightening and loosening the bleed nipple a few more times, then snug the bleed nipple down tight and turn the engine off. NOTE that you may see some of the coolant evaporate off of hot surfaces, especially if some was spilled on the exhaust header - this will subside, but best not to breathe the white steam and those fumes if you can avoid it.
36. Remove the clear tubing from the coolant reservoir and secure it in such fashion the end is held up high enough and the coolant that may remain in the line to the bleed nipple does not run out.
37. Put the coolant reservoir cap back on.
38. It's best now to let the scooter sit and cool off for a while - an hour would be good. This makes it easier to finish, but if you don't want to wait and proceed from here just remember that everything is HOT at this point!
39. Double-check the water pump hoses and clamps for leaks.
40. Carefully remove the clear tubing from the bleed nipple, and if it has coolant in it you can save this back to your coolant bottle. Set the tubing aside to rinse out and use again in a couple years...
41. Ensure the bleed nipple is tight to the engine block, and place the bleed nipple boot back on it.
42. Install the left side access cover panel with the Philips head screw.
43. Leave the coolant reservoir access cover panel off until the scooter completely cools off, and then check the coolant level in the reservoir; the level should be between the top and bottom of the short filler neck on the reservoir. Top up with fresh coolant if needed. Reinstall the coolant reservoir access cover plate with the Philips head screw.
44. Clean up and properly dispose of or recycle the old coolant. And you can remove your eye protection now...
And you are now done! A couple further notes to read as you sip your cold beer...
The manual specifications say there is ~1.8 liters of coolant in the Mp3 500 cooling system and I was able drain out and replace about ~1.5 liters this way, judging from how much coolant was used to replenish (and the tilde meaning "about"...). I'm sure there are other tricks that might be used - maybe tilting the scooter? - to get more coolant to drain out, but I am satisfied enough coolant is replaced this way for another two years' riding!
Next few rides keep an eye on the temperature gauge for normal operation, check your new hose clamps on occasion, and check the coolant level as well and be sure it stays at the correct level. If the temperature is running high there may possibly still be air trapped in the engine block and it would need to be bled again, but this is very unlikely if this procedure here was followed.