Chevy Impala SS Forum banner
1 - 5 of 5 Posts

·
Premium Member
Joined
·
1,047 Posts
Discussion Starter · #1 · (Edited)
This past weekend, I installed a new Delco opti, new Delco water pump, thermostat, plug wires, and O2 sensors. In the process of doing the water pump install, I remembered a tip that saved me a ton of bleeding-time and hassle and thought I would post it here for future reference, along with some other tips that may save someone some time down the road. (For the record, the water pump, the opti, wires, and O2 sensors appeared to be original to the car - 120k.)

Now, as with everything on the interwebz, your mileage may vary. I've done this 3x now and using the method below, I've never had to open the bleeder screw more than once each time.

If you're replacing the opti, buy the complete FelPro timing cover seal kit. You won't need the timing cover gasket, but you'll be glad you have the seals, and it comes with the water-pump gaskets too. It's $10 or so.

I have found that getting the car on ramps up front will allow a 5-gallon Home Depot bucket to fit under the car and catch all of the coolant as it drains from the various locations.

When draining the coolant, do it in the following order to minimize spillage: First, pop off the tank-cap. This will allow the fluid to drain easier. Next - radiator drain - driver-side, lower corner. Turn it 1/4 turn and pull it straight back. Don't try to "unscrew" it. It's not a screw. Its a plug. Let it fully drain and remove the hoses from the pump. Next, unscrew the coolant temp sensor from the water pump. This will drain most of the coolant that would normally gush out when you remove the water pump from the block. (May as well replace it now, too...) Pull the remaining hoses from the water pump. Check and replace if necessary. Pull the 6 bolts on the pump - some will probably still spill out, but not much.

Very important step that is often skipped when installing a new water pump: get a hose and completely flush out the block and the coolant-tank. I mean, sit there with the hose blowing into the block until everything comes out clear. If you position your HD bucket correctly, you can catch most - if not all - of the water. (If you're super anal, you can remove the plug in the side of the block and ensure a complete flush, but its really not necessary.) Do the same with the coolant tank/heater lines coming off the water pump. Sediment and scale will wipe out a new water pump in short order.

If replacing the opti now (its the perfect time to remove and inspect it), you have to remove the balancer. Remove the 3 bolts on the balancer securing it to the hub. DO NOT BANG ON IT WITH A HAMMER TO LOOSEN IT. There is a chance doing so will tear/damage the rubber in the balancer. Use the correct puller

Once the balancer is off, use some emery cloth to sand the rust off the hub and the inside of the balancer.

Once the opti is off, you don't really have to replace any seals other than the opti/timing cover seal. If you don't replace this seal, you're tempting fate. Pop the old one out and install the new one. INSTALL IT DRY - DO NOT LUBE THE SEAL. Chances are, your water-pump drive seal is also leaking. The FelPro kit above comes with a new one, make sure you use the correct tool (or the sharpie pen cap trick) to install it. Surprisingly enough, my wp drive seal was fine. The Opti seal was leaking...

There are two o-ring seals on the opti-shaft itself. These are craptastic rubber and will most likely fail, if they have not already. I would strongly suggest replacing these seals with Viton o-rings. They are incredibly superior in every way to the crap that is installed OEM. I had to buy a bag of 100 since they don't sell them two at a time. I will send you the correct Viton seals for $5 - shipped anywhere in the CONUS. PM me if you need them.

Double and triple check that you're connecting the plug-leads to the correct opti terminals. Use d/e grease. Replace your vac lines from the opti to the manifold and use the correct one-way valves. Before you re-connect everything, temporarily hook up the MAF to the intake and re-connect the opti leads and fire up the car to make sure you've connected all the plug leads correctly. You'll know immediately if you did not. Running the engine "dry" for a few seconds will not hurt anything and you'll be VERY glad you did

Install everything back onto the car with the exception of the hoses, water neck and thermostat. Attach the hoses to the radiator if you've taken them off.

Take 1 gallon of coolant/water, and slowly pour it into the thermostat housing. The engine will take almost the entire gallon. Fill it right up to the brim of the opening until it starts dribbling out. Use some wire/rope/hanger/assistant's hands to position the lower radiator hose at the approximate level of the water pump connection. Take the upper radiator hose (water-pump side, other end connected to the radiator), and slowly pour your mix into the hose, letting it percolate down into the radiator until it starts to come back up the lower hose. Once the radiator is full, connect to the water pump.

Take the coolant expansion tank line to the water pump and plug it, leaving the other line disconnected. Fill the expansion tank with your coolant mix until it starts coming out the disconnected line. You may have to blow/pressurize the tank somewhat to get it to flow all the way through the heater core and come out the hose. Once it does, connect the lines back up to the water pump.

At this point, the only thing left to do is install the thermostat and neck. Before you do, however, pour more mix into the opening to completely fill the radiator hose. Then install the t-stat and and neck. Do NOT use any silicone here - the t-stat IS the seal.

Turn your HVAC to heat, and full-hot, and start the car. This will quickly circulate any air out of the HVAC system and make it easier to burp. There probably won't be any air in here if you did this correctly - but its a good 'safe practice'. *Check for leaks while the car is warming up. Let the car get up to temp - watch the fluid level in the tank, and watch the temp gauge closely. Once the car reaches operating temp, crack open your bleeder screw with a rag under it to catch the runoff.

You should have just the smallest little hiss of air before the coolant starts coming out. I'm talking about a half second or less, since you effectively eliminated all the air when you filled it. Close it back up and go for a drive to ensure it doesn't get hot.

That's it.

You can probably do the water-pump and opti R&R in 2-3 hours, taking it easy. Its far from a difficult job. (Removing my headers to drill out and Heli-Coil the O2 bungs took another 3 hours and was far more aggravating...)
 

·
Registered
Joined
·
2,197 Posts
working by my self at 75, it's hard to bleed the air.
Work slowly. The slower you pour in the coolant, the less burping it'll need.
If you can, tilt the nose up a bit when you pour it back in, leave both the bleeder screw and the reservoir cap open as you're pouring in, and put something under the bleeder to keep or divert coolant away from the Opti so it doesn't get pee'd on.
Why only remove one knock sensor, how about both to flush block? Should I reuse the knock sensors?
If you somehow manage to remove both knock plugs / freeze sensors without damaging either one, congratulations.
Usually people who plan on removing them buy replacements just in case because of the likelihood of damaging either or both by trying to remove them.

atlantadan's procedures above are worth implementing.
Wherever I just contradicted him, go with what he says.
 
  • Like
Reactions: atlantadan

·
Registered
Joined
·
8,652 Posts
All of it, both -dan and Marky-. I do less of a methodical component refill than -dan outlines, but most definitely force flush hose water into the engine to get it clear. DO NOT force hi pressure through the heater hoses, just enough to run clear. One thing I've had great luck with is with front raised a bit to fill and run to temp with intermittent burps until it starts to heave out of the recovery tank, then cap it turn off and leave several hours . Amazing how much the tank gets drawn down once or even twice while cooling.
I didn't catch above, but get as much flush water out of everything and then only distilled water with the coolant.
 
  • Like
Reactions: atlantadan
1 - 5 of 5 Posts
Top