Water pump and coolant related question

[DWBOX2000]

How come before the water pump is removed the coolAnt needs to be drained though the manifold drain plug? Is it because the water pump is at the lowest point and it will all drain out when removed?
Also I need to fill and bleed the system after the wp installation. The instructions say to fill coolant to bottom edge of filler neck. Does that meAn fill the filler neck until it is at the absolute bottom of the tube or fill to the minimum line or something else? Then after letting engine idle it says to top off as much as can when idle is slightly raised. What does that mean? Sorry, the vagueness of instructions is driving me crazy. Thanks.

[thstone]

The water pump may not be the lowest point, but its low enough such that if the coolant isn't drained before the water pump is removed, a large amount of coolant will come rushing out and splash everywhere as soon as the water pump seal is broken. Even after the coolant is drained, you'll still get a little bit of coolant coming out from behind the water pump but it can be cleaned up with a few rags. To avoid a really big mess, follow the instructions and drain the coolant into a pan before removing the water pump.

[DWBOX2000]

Thank for responding. I went ahead and removed following the instructions. Probably 4 gallons came out. Not so bAd.
Took water pump off, it was the original with almost 50k on it. Looked like new. spun like new, zero play in the bearings. Ughhh! No way I am doing the aos any time soon. I'll wait for symptoms. Put back together tomorrow.

[fins]

How long does install take? Shop manual estimates 6 hours??

[DWBOX2000]

Could be right. With a lift and better tools probably 3-4 I bet. Like anything, the first time is the worst. Hose coming off the wp took a 1/2 hr. Honestly, I think paranoia came over me. Unless it is rattling, I will not do again. I seem to read over and over that people pull stuff out just to find out nothing is even close to wrong. Yes people do have problems but I am starting to wonder if some of the issues are help along with driver input. I am now in the camp that these cars are well built and are dependable, they are not the time bombs some have us believe. I will probably just follow Porsches guidelines for now. I feel better now, thanks for reading. 😁

[Jager]

Originally Posted by DWBOX2000

Could be right. With a lift and better tools probably 3-4 I bet. Like anything, the first time is the worst. Hose coming off the wp took a 1/2 hr. Honestly, I think paranoia came over me. Unless it is rattling, I will not do again. I seem to read over and over that people pull stuff out just to find out nothing is even close to wrong. Yes people do have problems but I am starting to wonder if some of the issues are help along with driver input. I am now in the camp that these cars are well built and are dependable, they are not the time bombs some have us believe. I will probably just follow Porsches guidelines for now. I feel better now, thanks for reading. 😁

Why did you replace the water pump?

[DWBOX2000]

Because I am a fool. Stupidly I bought before I checked the bearing for play. I ordered and then checked and even though fine, I though maybe the fins are starting to wear. Heck I read a All these horror stories. No looked great. I was going to do the aos next. I've decided to leave be and periodically check when I change the oil. I am changing my ways.

[fins]

Originally Posted by DWBOX2000

Could be right. With a lift and better tools probably 3-4 I bet. Like anything, the first time is the worst. Hose coming off the wp took a 1/2 hr. Honestly, I think paranoia came over me. Unless it is rattling, I will not do again. I seem to read over and over that people pull stuff out just to find out nothing is even close to wrong. Yes people do have problems but I am starting to wonder if some of the issues are help along with driver input. I am now in the camp that these cars are well built and are dependable, they are not the time bombs some have us believe. I will probably just follow Porsches guidelines for now. I feel better now, thanks for reading. ��

I've mentioned this before in older posts but I replaced a perfectly good double row IMS bearing with a brand new double row IMS bearing. Live and learn

[DWBOX2000]

Done, putting back in was easy. Borrowed torque wrench from autozone. No leaks. 7 ft lbs is not very much so if you don't have one, go light. The only other tip I found is to work from the side if using ramps. Makes it much easier. Also, since the bolts are different sizes, I kept the bottom outside and latex the upper ones in the pattern that they were in. Worst part is doing the jacking and removing hose from pump. I warmed up with heat gun and then pushed a chisel with a rounded edge in and worked my way around ( as possible). Them I pushed in until it just past the metal edge of the pump and pried off.

Not sure I did the antifreeze refill correct. Went to operating temp and remained there. I let idle for a while, while revving to 2500 every so often. After 10 mins, I topped off and would rev up to 4000 or so. Instructions did say 5k. Had pressure value up the whole time. Anyhow I put away and everything seems ok. I will carry some fluid for a while as a safety net. It took 2 gallons of fluid, about what came out.

[PaulE]

I thought I had read or heard that the plastic impeller can fail just because of heat cycles, even if the water pump bearing is fine. Flat 6 Innovations says this on their website -

"Replace the water pump, water pumps can fail silently and lead to cracked heads! Replace the water pump no matter how many miles are on your car, as time in service kills the plastic impeller blades of the pump, not miles!! Water pumps are cheap insurance, if a water pump creates a cracked head and intermixed coolant and oil exist the costs can be over 15,000.00 for repair"

So just because it looked great when it came out doesn't mean it had a lot of life left in it - you've re-set the clock on time in service and have that peace of mind.

What I thought that I had read, or heard, was that the thermal heat cycles eventually create cracks in the plastic impeller, and then bits of the impeller break off and wander through the cooling system and then can get caught in small places in the cylinder heads leading to hot spots. And that this could happen even if the water pump bearing was not failing.

When I had my water pump replaced proactively about 2 years ago at around 42,000 miles, on my 2003 S that I bought new, my independent shop thought it was a good idea to go with a metal impeller water pump. I'm now at over 55,000 miles and so far so good. Since I had my water pump replaced, I've found this forum and the general consensus seems to be stick with OEM plastic impeller water pumps. I will keep an eye on the bearing and proactively replace it again down the road. I'll revisit the plastic vs metal impeller again then, but for this time I felt the risk of plastic outweighed the risk of metal.

[JFP in PA]

Originally Posted by PaulE

I thought I had read or heard that the plastic impeller can fail just because of heat cycles, even if the water pump bearing is fine. Flat 6 Innovations says this on their website -

"Replace the water pump, water pumps can fail silently and lead to cracked heads! Replace the water pump no matter how many miles are on your car, as time in service kills the plastic impeller blades of the pump, not miles!! Water pumps are cheap insurance, if a water pump creates a cracked head and intermixed coolant and oil exist the costs can be over 15,000.00 for repair"

So just because it looked great when it came out doesn't mean it had a lot of life left in it - you've re-set the clock on time in service and have that peace of mind.

What I thought that I had read, or heard, was that the thermal heat cycles eventually create cracks in the plastic impeller, and then bits of the impeller break off and wander through the cooling system and then can get caught in small places in the cylinder heads leading to hot spots. And that this could happen even if the water pump bearing was not failing.

When I had my water pump replaced proactively about 2 years ago at around 42,000 miles, on my 2003 S that I bought new, my independent shop thought it was a good idea to go with a metal impeller water pump. I'm now at over 55,000 miles and so far so good. Since I had my water pump replaced, I've found this forum and the general consensus seems to be stick with OEM plastic impeller water pumps. I will keep an eye on the bearing and proactively replace it again down the road. I'll revisit the plastic vs metal impeller again then, but for this time I felt the risk of plastic outweighed the risk of metal.

Not to be a wet blanket, but Porsche uses a composite impeller for a reason: The rear of the impeller has to be very close (few thousandth's of an inch) to the engine case in order for the pump to work. When the bearing wears, and it will, the impeller will start to wobble a bit, and can actually hit the engine case; if it is composite, the impeller can snap off, if it is metal, the impeller will start to tear up the engine case and do irreparable damage to the soft aluminum engine case. Besides now filling up the cooling system with ground up aluminum, when a new pump is installed, it is too far from the engine case for the pump to work effectively.

Use a composite impeller pump, not a metal one.