Water Pump Debate: Plastic oe metal impeller?

3206 Views 10 Replies 8 Participants Last post by cchief22, Jul 26, 2018

Sizzle

Discussion Starter · Jul 25, 2018

04 1.8t AWM
Recently I replaced the coolant flange and temp sensor. Afterwards, a problem arose that had only happened once previously. It would overheat while driving, but stable at idle. My first thought was air bubble, because it wasn't overheating at idle. Bled the coolant at the heater core flange, still no change. (breaking the flange pipe in the process, but that's another thread) Next step was to replace thermostat, and it appears to be fine now. Today, one day later, I notice leakage coming from a location that I can only speculate, is the water pump. I expected to have to replace it soon, but not this soon. Then I come across this video explaining how the impellers separate and may not over heat at idle, but will while driving. (I'll post the video below) So now, I'm nervous that this particular type of failure can be intermittent. Any thoughts on that??? And of course, should I buy a pump with plastic or metal impeller???

https://youtu.be/YbzDJqPIUrA

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2004 1.8T BBS

· #2 · Jul 25, 2018

Water Pump Debate: Plastic or metal impeller?

I had to have my water pump "serviced" at 68k miles, but I just replaced mine in March (161k miles).

Definitely go with metal impeller, as the plastic ones tend to break down over time.

As far as your leak issue is concerned, definitely sounds like a new water pump will fix it. Just make sure you also do the belts, idler, and tensioner pulley.

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AndreasPassat

· #3 · Jul 26, 2018

Debate?
Only people who are to cheap and don't care about doing repairs twice for the same problem would opt for a plastic impeller.
Yeah it's kind of a harsh statement and I apologize for that, but having gone down this road repairing other peoples cars and they hand a cart full of cheap-o-Chinese-crap, only to do the same job again within months.

Please do yourself a favor and for ultimate peace of mind while your engine is spinning at 3000 RPM cruising down the breezeway, install a metal impeller.

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Sizzle

Discussion Starter · #4 · Jul 26, 2018

Lol... 10-4

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ylwagon

· #5 · Jul 26, 2018

I've had to change two broken plastic impeller-pumps in 1.8Ts: a 2002 Jetta and our '99 Passat. Both got new metal impeller pumps. That being said, plastic impellers have some advantages and may in fact been improved in the last 15-20 years. They have less mass/inertia, therefore accelerate and decellerate with less force, are smoother and probably require less energy to run, and are also likely better balanced out of the mold. Blauparts has touted their improved plastic impeller pumps since about 2010.

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AndreasPassat

· #6 · Jul 26, 2018

ylwagon said:
I've had to change two broken plastic impeller-pumps in 1.8Ts: a 2002 Jetta and our '99 Passat. Both got new metal impeller pumps. That being said, plastic impellers have some advantages and may in fact been improved in the last 15-20 years. They have less mass/inertia, therefore accelerate and decellerate with less force, are smoother and probably require less energy to run, and are also likely better balanced out of the mold. Blauparts has touted their improved plastic impeller pumps since about 2010.

You are absolutely correct. Plastics have come a long way through the years. Crying out loud, I work with some plastics that are more difficult to machine than steel. But psychologically there's something about spinning plastic inside my engine that my brain says, this just isn't right.
Now if they could mass produce these with an aluminum impeller that's threaded on onto that stubby little shaft, now we'd be talking. Maybe even make a little rebuild kit. Oh the humanity of it all.

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VAGguy

· #7 · Jul 26, 2018

Peace of mind, metal impeller. My OEM plastic one shattered at 64k miles. Replaced with a GEBA metal pump, went 86k no issues. Have had another GEBA pump in there since about 150k. At 170k now and no signs of any issues or leaking.

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kutcht1

· #8 · Jul 26, 2018

I would go with a Graf or Hepu pump. But I would also suggest that you do a complete timing belt and pulley with new tensioner also. I also have heard of people having early failures of a plastic pump impeller. I went with a Graf on my Passat but went with a Hepu on my BMW, was impressed with both.
TomK

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cchief22

· #9 · Jul 26, 2018

metal,no doubt, TB as suggested while you are there, plastic may have lost a piece, which will find its way into system (turbo !) and create more pieces, a lot of nooks and crannys, when you do this pull off little stub plug in return line by oil filter housing and see if anything (little pieces) have "dropped" in as they pass by. side bar ,still have not figured out why thermostat is recommended in the Bentley to be installed with a "bridge" in vertical position ...regards Chief

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jimothy

· #10 · Jul 26, 2018

I rebuilt an audi A4 1.8t a few months ago that had a warped head from overheating, tore into it and found the water pump impeller busted into pieces and plugged up several of the cooling ports in the block as well as in the head. Had to adapt a small plastic hose to a shop vac and suck some of the pieces of plastic out of the block, and work others out with a pick. Had to disconnect and clean out all the coolant hoses, it was a time consuming deal. Having to have done that makes me partial to the metal impellers.

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cchief22

· #11 · Jul 26, 2018

while doing WP and TB .get access to turbo supply line, pull and check banjo fitting and bolt (8mm allen) mounted to engine block, located in front of starter, above and behind AC compressor ( for collected/trapped crap in the bolt), it has a couple of small holes , like a clogged artery..!!!, it gets restricted and you can be flirting with trouble, any restriction there only contributes to oil supply to turbo doing some cooling, and oil ends up baking to coke..... surprised no one has invented a see-thru inline filter that would mount to top return line on the 1.8s between hard tube and top radiator bayonet hose connection.

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