Changed out the water pump and thermostat as part of the coolant flush today. Preventive maintenance, old pump was still beating but at 90K it's statistically reaching the end of its life. Car is a 2007 3.0si manual, N52 engine, 90K miles. Old water pump and thermostat were both OEM.
First of all, some observations that might help people DIY this:
- Both the water pump and thermostat are easy to get to (thanks to the mile-long engine bay). I jacked up the PAX side of the car, put a ramp under the wheel, and used the center front jack point to jack the whole front end up and put it on jackstands. Remove the center plastic cover and the water pump and thermostat are readily accessible on the PAX side of the engine block.
- I drained the expansion tank and radiator first - still coolant flew everywhere when uncoupling hoses from the units. Have some shop towel ready!
- Thermostat has two hoses that are connected via a plastic coupling. Most DIY instructions I've seen tell you to use a screwdriver or plier to pull the wire clip away from the housing. For the larger coupling however I found it easier to push on the two ends of the clip with your fingers to release the coupling. The tab where you'd insert the screwdriver is above the coupling, so if you're under the car there's no way to see it without a mirror.
- The said plastic couplings were a pain in the ass to remove. They're glued tight (weather effects, not actual glue) to the aluminum thermostat. I heated the coupling up and used a small amount of WD-40 to finally get them apart. You can't twist these couplings - they have alignment features built into them, so you'll need to sort of wiggle them.
- Hoses secured with worm clamps may be glued tight too. These are a lot easier - gently use a small screwdriver or plastic trim removal tool to break the bond (you only need to get about 180 degrees of the hose periphery) and wiggle them again. They should gradually come loose.
- There are 3 single-use bolts on the water pump. 2 are easily visible, the 3rd one is not the first bolt you see. If you look above the water pump you'll see a blue headed bolt that look exactly like the other 2, but the one you want to remove is about an inch forward of that and can be hard to see.
- The sequence of removal I found to work the best:
- Disconnect electrical connectors from both water pump and thermostat
- Decouple all hoses connected to the thermostat (should be 2 plastic couplings and 2 worm clamps)
- Disconnect thermostat from water pump (2 10mm hex bolts)
- Decouple 1 hose connecting the water pump to the car (should be the smaller one, there are only 2 hoses going to the water pump and the larger one is a small U-hose going to the thermostat)
- Undo the 3 bolts holding the pump to the block and discard bolts
- Remove water pump
After the new pump and thermostat are in and doing the bleed procedure twice (and verifying no leaks multiple times), I turned on the car. First warning sign, no hot air coming from the A/C. I plugged in my code reader and found 2E83 power reduction operation. Car was at normal operating temperature at this point, so I cleared the code and restarted the car. Re-scanned for codes, and 2E83 popped up again. Not 1 minute later the radiator fan kicked into overdrive and the temperature gauge went to about the 2'o clock position. Shut the car off before any warning chimes or lights, radiator fan stayed on for about 2 seconds and turned off. I don't think that caused any lasting damage to the car.
I'm wondering if I got a defective pump - everything was installed per spec and double checked, torque wrench used on all bolts, no leaks. Unless there's a hidden procedure I missed required for "breaking-in" new pumps? I'm going to try and put the old pump back in tomorrow and see what happens.
Check fuses, as you have an electric pump.
Any updates? I am considering DIY for this myself soon.
There is bleeding procedure for the electric water pumps
He posted that the bleed procedure was performed twice, hopefully the correct one, for electric not mechanical pump!
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