by AlfaBits Editor Erik Roe

It has been a while since I wrote a technical article featuring my Milano. As you may remember, I bought it used (big surprise, huh?), with about 57k on the clock and a handful of items needing attention. It now has over 105k and is running very well. Recently, it was due for another water pump. The pump bearings wear, which lead to seal failure and other nasty things. Fan belt tension is the primary load on the water pump bearings. The basic layout of engine front pulley, water pump and alternator is identical to the four cylinder, one V-belt transferring engine power to the water pump and alternator. Except, my experience has been that, in general, the four cylinder water pump bearings last much longer (100k?). 

Anyway, water pump bearing failure is a very common service item for the Alfa V6. Looking back on my records, each water pump (yes, this is the third one) has lasted just about 30,000 miles. I have replaced each one upon the point that the noise from the bearings is very noticeable, but before the pump starts leaking any coolant. Some people say the weak design is intentional. The premise is that it results in a new timing belt every 30,000 miles. I am not sure that is true, but it may be possible! My understanding is that the 164 shares the same problem, comments? 

I do know that replacement of the water pump is fairly easy and can be quite rewarding, considering the amount of work required. A quick test of the water pump can be executed by simply grabbing (engine off, of course) the end of the water pump pulley and wiggling it up and down (See figure 1). If you can produce noticeable movement, the pump bearings are on the way out. The second test is to listen for grinding from the pump as the engine is idling (standing in front of the car with the hood up and your ear down by the front of the engine, be careful of the fan!). If you can hear it grinding, it is due for immediate replacement. Alternator belt tension is the key to pump life, make sure it is only as tight as needed. I keep mine with about one inch of slack when pushing on the belt (figure 2) with your finger (engine off!). 

First a brief overview. To replace the water pump, you have to drain the coolant, remove the air flow sensor and air flow sleeve, remove the spark plugs wires and distributor cap, remove the accessory drives (fan belts), remove all the shrouding on the front of the engine, set the engine up on top-dead-center (number 1 cylinder on firing stroke), remove the timing belt, remove and replace the water pump, replace the timing belt (preferably with a new one), check the valve timing, check the valve timing again (this is an Alfa, not a Subaru, you cannot operate the engine without damage if the valve timing is off, but hey, it sounds a lot sweeter than any Subaru I have ever heard!), put all the shrouding back on, replace the accessory drives (fan belts), air flow meter, ignition system, refill with coolant and you are done! That doesn't sound so bad, and it is about a Saturday's worth of work (4-6 hours) if you are careful and have all the parts on hand. 

Second, a list of the parts required. If you want to simply replace the water pump you should have the following: 

V6 Service Manual (The Club Library has one) 

New Water Pump 

Original Equipment (OE) Type Gasket for Water Pump 

Thermostat Housing OE Gasket 

New Timing Belt 

Fan Belts (if required) 

Since I have found this to be a regular service event, I also replace the following at the same time: 

Distributor Cap 

Distributor Rotor 

Spark Plugs 

Antifreeze 

Spark Plugs well seals 

Depending on which parts you choose to replace, the parts alone will cost you something just over $150 (also depending on where you purchase the parts). Of course, you also need a set of tools and a large drain pan (the Milano holds about 2.5 gallons of coolant). I assume you have these. If you only have a $99 socket and wrench set, and have to work in a less than ideal place (apartment carport) please take your car to your favorite Alfa mechanic, else you may get in too deep. 

Photo 1 shows the engine before any disassembly. The water pump is located just under the thermostat. The thermostat is the item on the front of the engine that has the two large radiator hoses connected to it (each about 2" in diameter). Note that the nose of the pulley is the point you grab to test the conditions of the water pump. 

Photo 2 is a close up of the engine pulley with the v-belts and timing belt covers removed. The top-dead-center mark ("P") is at the pointer, check the distributor rotor at the same time. Photo 3 shows the rotor's approximate position (roughly 10 'o'clock). There is a mark on the edge of the distributor body that will line up with the rotor (plus or minus a few degrees depending on the static ignition timing). If you are not on the firing stroke of #1, you will be 180 degrees out at the distributor (camshafts and distributors rotate at one-half engine speed). Setting the engine on top-dead-center before you remove the timing belt is critical, so take the time to be sure. 

Always approached engine top-dead-center rotating the engine clockwise as viewed from the front of the car looking at the front of the engine. I like to have the car in 3rd gear and I simple roll the car forward, by rolling the front tire, while watching the timing pointer. If you overshoot the mark, knock the car out of gear, roll it backwards and try again. Avoid, at all costs, rotating the engine backwards. 

If you have not done this sort of thing before, I would recommend you remove the valve covers and check the timing of the cams before you remove the timing belt. The cams have timing marks that will align with marks on bearing caps. On the right-hand cylinder bank (passenger side) cam, the timing mark is on the third bearing cap (from the front), while the left hand side cam has its mark on the second bearing cap. Now that you have the valve covers off, you can replace the spark plug well seals and stop that oil leaking into the spark plug well. Photo 4 shows the right cylinder bank cam set up correctly (note the lobe positions, as the actual timing marks are probably not visible). 

Now that you have the engine set up, loosen the timing belt and remove it. If your engine has the original equipment belt tensioner, you will need to loosen the two mounting nuts and then rotate the unit clockwise out of the way and "pin" it. Figure 3 shows this operation. The Factory tool is a pin as shown, but I have found that a 3/16" drill bit will work (or something close to that diameter). As you attack this device, you will see what is required. Upon loosening the belt tensioner, you are ready to remove the belt. 

The next step is to remove the distributor drive pulley. Ideally you would use the tool pictured in photo 5. This is the factory wrench that allows you to hold the pulley while removing the securing bolt. If you do not have this wrench, or access to one (I think the club has one . . .), you may wish to loosen the securing bolt before you remove the timing belt. If you choose this method, leave the car in gear and firmly set the parking brake to prevent engine rotation from torque applied to the bolt. I would recommend using the wrench, if you can. The pulley may not just "fall" off the shaft it drives, but it is not a taper or interference fit. Tap it lightly with a plastic mallet and it should come free. 

Photo 6 shows the engine ready to have the water pump removed. Loosen the clamps on the short pieces of water hose connecting the cylinder heads to the thermostat. Next remove the 12 bolts holding the pump to the engine block. Some of these may show signs of corrosion. Use a plastic mallet or similar, if required, to break the gasket bond from the block and pull the pump and thermostat assembly away from the engine. Photo 6a shows a new pump and the old one (thermostat assembly still attached). The thermostat assembly is easier installed with the pump off the engine. 

Photo 7 shows the engine upon water pump removal. You will want to take some time to clean up the gasket surfaces and probably the front of the engine. Now is a very good time to install a new timing belt tensioner. I installed the new Alfa temperature actuated belt tensioner on my car about 10,000 ago. You can see it in the lower left between the engine pulley and the air conditioning pump in photo 8. 

This type of tensioner does not use the engine oil pressure, only the heat of the block to adjust the belt tension. If you do not have the new tensioner, I would recommend installing one. It will eliminate that little oil leak that is from the original tensioner (for more information, see Ed Ng's excellent article on this little device in the November '93 issue of Alfa Bits). 

To clean up the water pump mating surface, I used a 3M scotch brite pad (medium grade?) and some solvent. This gives you a little bit of abrasive to remove sealing compound, but will not leave a lot of particles like steel wool would. A nice clean surface will help ensure a good seal. This is also a good time to replace, if desired, those short pieces of radiator hose connecting the cylinder heads to the thermostat. While they will probably never burst, the aluminum tends to corrode and creates a leak path. New rubber seals better and cleaning up the aluminum surface help reduce the risk of leaks. The inside diameter is metric, but a decent auto parts store will have an inch size hose that will work well (1-1/8", I think?). 

Now that you have the thermostat mounted to the new pump, using a new gasket and a sparse amount of your favorite sealing compound, you are ready to mount the new pump to the block. Again you will want to use a new gasket and a small amount of sealing compound. Those 10 mm hex bolts need only 6.5 ft-lbs of tightening torque, so be careful not strip out the threads in the block! Also note that the bolts vary in length, with the longer ones occupying the thicker section of the pump casting. With the pump reinstalled and short radiator hoses clamped to the thermostat, you are over the hump on your way to completion. 

Re-fit the drive sprocket to the distributor drive and align the rotor to the mark on the distributor body (top-dead-center, #1 firing stroke). You are now ready to install the new timing belt. Double check that the engine (front pulley) is on "P" and that the cams have not moved. Slip the belt onto the front pulley, around the tensioner and over two of the three driven sprockets. You will find it more difficult installing the new belt than it was removing the old one (no big surprise). 

My advice is be patient. You will want to get the belt around the distributor drive and then try to slip it partially onto the driver's side cam sprocket. By partially I mean only half of the belt's width. Then carefully slide the belt onto the other camshaft pulley. Do not use a pry bar or screwdriver to help accomplish this step. The belt will slip on with little effort, but you must have things just so. I know that description is vague at best, but you must not damage or crimp the belt during installation. Else you may find it breaking on you! Remember that comment about the Subarus? It is about this time that your back is pretty tired from stooping over your lowered car, so take a break and then come back to finish! 

So you have the new belt in place. Now you need to set the tensioner. With the old style, you simply bring the roller firmly up against the belt, tighten the mounting nuts, and release the spring system by removing the "holding pin". If you have a newer thermal tensioner, you put a 3/8's drive, 3" extension into the square hole at the lower point of the casting and use a ratchet to tension the unit's clock spring until the arrows line up. Photo 8 shows this process. Note that you should set this unit up when the temperature is between 55 F and 90 F (as per the Alfa specifications). Make sure that parallax error doesn't prevent you from correctly setting the tension. A parallax is that visual error you get when you try to read the speedometer while in the passenger seat. I used a small mirror to ensure proper alignment. 

Now that you have the belt tight and all the timing marks are still in the correct positions, put the car in gear, release the parking brake and roll the car forward to rotate the engine through several revolutions. This allows the belt to seat a little and ensures that you have the timing correct. You should be able to come back around to top-dead-center and have all the marks line up. If not, you need to remove the belt and try again. If the engine refuses to rotate, do not force it. You may have a valve against a piston. If this occurs, you need to get some help (tech hotline), but if you are careful, things will go well! 

With the timing belt installed, you can proceed to reassemble the engine. Start with replacing the valve covers, the timing belt shrouds, the V-belts, the radiator hoses, the ignition system, and finally the air flow meter and air flow sleeve. Refill with fresh coolant, bleed the air from the system at the thermostat (14 mm hex plug) start up the engine and look for leaks. Watch for loose hose clamps. Good Luck!