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2007 Lucerne coolant leaks


Mudbone
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The plastic elbows were leaking on the Lucerne. I decided to replace the water pump, thermostat, Idler pulley and belt. Used aftermarket aluminum elbows. I couldn't find the radiator drain. I googled it and a guy said they didn't have any. So I just pulled the lower hose. I removed the thermostat and filled it with radiator flush and water. I pulled it out in the driveway and flushed it three times. Put the new thermostat in and filled it with new coolant. Now I have to get the wheels powder coated and get some new tires on it.

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New aluminum elbows are cheap too. In the Help section usually.

 

Having several 3.8s I'm used to this elbow repair. I replaced one water pump because I couldn't stand the noise of the bad bearing unit, never leaked!🤔

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  • 2 weeks later...

That elbow was not one of GM's better engineering decisions.  I had to do that job on my 07 LaCrosse too.  Another bad GM engineering decision on these cars were the o-ring seals in the tranny.  Sub par o- ring material caused leakage which led to slippage which led to rebuild.

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The o-ring that was a great idea when new is the o-ring on the Northstar V-8 water pump.  With the special tool, to install, you just put the pump "cartridge" in the hole and turn to lock it in.  Quick and easy to do when new, on the assy line.  But at about 100k miles, when the pump needs replacing, you'll probably break the tool to get the failed pump out.  That thin o-ring (around the circumference of the pump body) has lost all of its installation lube and now must TURN in its groove to get the pump out.  Aftermarket tools usually break, as can the OEM-spec GM/Kent-Moore tools, too.  Not nearly as "neat" as it first appeared to be!

 

Those right-angle heater connections are very minor, by comparison, to the NS water pump o-ring seal.  First time or two our guys changed a water pump with the "re-designed" situation, they broke the plastic connector.  I figured that after 80+k miles of hot/cold cycles, the plastic was a bit brittle anyway.  Discovered that NAPA had them in stock, so after having to buy-out the second one, I put three in stock and then let the computer take the stocking level over from there.  I know the metal might look more substantial, but I know that if the plastic ones will last 80+K, or as long as the OEM water pump, that's what I'd use, but "whatever is available" is more operative, I suspect.  On the later versions, where the two connections/heater pipes attach to the front casting, those should have TWO o-rings on them, with a retention bolt holding them in.

 

Just some thoughts,

NTX5467

Edited by NTX5467 (see edit history)
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  • 3 weeks later...

Great tips - I agree with use of the 'snotty' undercoat; it will outperform paint in this case.  I'd seriously consider sealing the heads of those plastic rivets with RTV or similar.  It looks to me as though brine picked up and pushed through those openings by the front tires caused the rust damage that you discovered.

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I finally got the wheels back from Powder Coat. I had my new tires mounted and balanced with new tire pressure monitors. I just have to take the car in so they can calibrate them. We drove it yesterday and now it feels like a new car again. These tires are very quiet compared to the old ones. I hope we can get four more years out of this car. It has been a good one.

 

 

Edited by Mudbone (see edit history)
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  • 2 weeks later...

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