So I've got a 2006 3.5l and I find a lot of coolant on the horizontal crossbeam between than runs across the car in front of the water pump and behind the radiator. Is seems to be spraying from somewhere there since I cant trace it back to its source. The weird part is I cleaned everything up, got a pressure tester and I cant reproduce the leak. A quick drive around the block however and there is coolant all over the crossbeam again. I cant make it leaking by running the engine at idle either. What would make it only leak when driving?

 

Hi B.J.,Sorry 2 read about your problem. I know there's more pressure on your system while driving then sitting @ idle.
Have you flushed your total cooling system ? How many miles on your 3.5L ? Have you ever replaced your thermostat ? Any sensors ?

I'm not a mechanic or tech, so I hope one of our expert tech member's can help you >>>>Good Luck<<<<

 

Hi BJ. Check out the below

Nov 25, 2013 - 14 posts - ‎3 authors
Anyone replace the Motor Coolant Temperature Sending Unit Sensor? ... Join Date: Feb 2006 ... Badge & Doorsill Overlays, GM G6 Logo Mats, Blacked Out Window Trim,.... It has the same location on my dad's 2007 3.5L G6.

We have the Largest Selection of Coolant Temperature Sensor for your 2006 Chevrolet Impala. ... Fits the following 2006 Chevrolet Impala Submodels. 6 Cyl 3.9L | LT, LTZ; 8 Cyl 5.3L | SS; 6 Cyl 3.5L | LS, LT ... All Engines | All Submodels ...

<FONT color=#222222>Aug 2, 2011 - Engine coolant leaks detected on some GM vehicles may be the result of... Carlo and Uplander, 2006-2010 Chevrolet Malibu and Impala, 2006-2007 Pontiac ...I have the 2008 Malibu LS 3.5L V6 with about 89,000 miles on it. ... theres a smallcoolant pipe above a sensor and that the clamp was broken. he ... <B><FONT color=red><<< ? ? ? ?

 

Update! it does still leak during the pressure test it just doesn't make its way so far toward the front of the vehicle making me think it gets on the belt and tosses it around. I haven't ran the car yet and I can only see coolant from underneath the vehicle. I just got the car with 123,000 miles on it. I flushed the coolant shortly after I got it. Haven't replaced much else yet. Does the 3.5l have the same coolant elbows that are notorious for going out as the 3.4l? What else besides that or the water pump is on the passenger side of the block could leak besides the water pump?

 

 

The coolant crossover/bypass gaskets could likely be the issue. There is one for each cylinder bank and they go where the lines run between in the diagram. On my 2007 they went out before 50K.

 

Ok, are there any write-ups on how to do this?

 

Not that I'm aware of. You could google it and see what you come up with. Try using both 'crossover' and 'bypass' in your search. When looking for the gaskets I found both terms used. It was not difficult at all. Remove the belt, remove the alternator and bracket and unbolting (not disconnecting the lines) the power steering pump to be able to push it aside, and pulling off a few coolant hoses. After that I think there were maybe 7 or 8 bolts to remove to take off the crossover (the part in the diagram with the filler neck) and you are there. I couldn't find Fel-Pro gaskets so I went with Victor Reinz brand and got both gaskets with priority shipping for under $20 from rockauto.com. I think this is everything I had to do but am not 100% sure as it was a few years ago. It should definitely be good enough to give you an idea of how comfortable you are doing it your self.

 

Doesn't sound bad at all. I'm going to start with the water pump first though since that is my primary suspect.

 

That is a really good part diagram. Where did you get it? I would like to see the names that go with those numbers.