3.5 Coolant crossover tube [Archive] - Pontiac G6 Forum

: 3.5 Coolant crossover tube


ph71ss
09-16-2012, 03:08 PM
Can somebody help me? I am tracing a coolant leak on my 07 G6 V6 and I don't know where the crossover tube is located to see if it is the problem. The leak seems to be coming from the rear head gasket at the passenger side corner, but I don't know if the crossover could be leaking and running down to that area from above somewhere. Can anybody tell me where to check the crossover tube to see if that gasket is leaking?
Thanks, Pat

greenman
09-16-2012, 03:56 PM
It's highly likely the crossover pipe gasket is the issue. They all fail eventually on the 07 3.5l. The replacement gasket is much improved. Has your powertrain warranty expired?

This may help:

http://www.autoserviceprofessional.com/article/91742/coolant-crossover-leak

ph71ss
09-16-2012, 05:01 PM
Yes I ran out of time on the 5yr. warranty. Sucks because it only has 55000 miles on it. Everyone says the crossover tube gasket is a major problem. I am just trying to find help in locating where it is on the engine so I can verify the problem or rule it out

greenman
09-16-2012, 05:33 PM
Best I can do:

http://www.g6ownersclub.com/forum/attachment.php?attachmentid=3473&stc=1&d=1347838360

Metalhead852
09-16-2012, 05:57 PM
The problem stems from GMs RA finish when they mill the block and heads.

ph71ss
09-16-2012, 06:24 PM
Thank you, GREENMAN. I was looking for a tube of some kind, didn't realize it was basically the whole front of the engine from one head to the other. Now I am even more convinced it is the head gasket because I saw no evidence of anything leaking on the front of engine. Thanks again

greenman
09-16-2012, 07:33 PM
You might try fluorescent coolant dye & a blacklight (Walmart used to sell them for 10 bucks) to localize it.

ph71ss
09-28-2012, 03:56 PM
Thanks for all your responses Greenman. Took it to a local shop that I trust and got a quote of $1475 for both head gaskets and crossover gaskets. My question is if the crossover gaskets were leaking, wher would I find the evidence? What I mean is where would I look for the coolant to be running down and could it leak down and run down on the block deck where it meets the head on the rear head? The more I read about this issue it seems the crossover problem is more prevalent than the head gasket problem. Do you have any more info that could help me determine the problem? By the way, there is no oil water mixing in either the coolant or the oil. Again thanks for all your help, Pat

greenman
09-28-2012, 05:03 PM
Why exactly do they want to replace the head gaskets? The crossover gasket leak is very common on that engine. The gaskets fracture with age but the fracture could be anywhere & there could be multiple fractures. Considering the low mileage, I would contact GM customer service & try to work out a deal with them. They often do deals on known issues if the customer is persistent enough & "reminds" them that it's a well-known common fault on the LZ4.

If that shop put dye in it you should be able to see where the leak is using any blacklight at night.

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Service Information 2007 Pontiac G6 | G6 (VIN Z) Service Manual | Document ID: 2134019
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#07-06-02-006A: Coolant Leaking From Engine (Replace Coolant Crossover Pipe Gaskets) - (May 12, 2008)


Subject: Coolant Leaking from Engine (Replace Coolant Crossover Pipe Gaskets)


Models: 2006-2007 Buick Terraza

2006-2007 Chevrolet Impala, Malibu, Monte Carlo, Uplander

2006-2007 Pontiac G6, Montana SV6

2006-2007 Saturn Relay

2007 Saturn AURA

with 3.5L or 3.9L Engine (VINs N, K, I, R, W -- RPOs LZ4, LZE, LZ9, LZ8, LGD)




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This bulletin is being revised to update the labor code in the Warranty Information section. Please discard Corporate Bulletin Number 07-06-02-006 (Section 06 -- Engine).


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Condition
Some customers may comment on coolant leaking from the engine.

Cause
The gasket located between the coolant crossover pipe and the front of the right (rear side) cylinder head may be leaking.

Correction
Replace the coolant crossover pipe gaskets with current service replacement gaskets, P/Ns 12577704 and 12590668. Before installing the new gaskets, make sure that the mating surfaces on the crossover manifold and cylinder head are completely clean and that NO OIL or OIL RESIDUE exists.

Parts Information
Part Number
Description
Qty

12577704
Gasket, Coolant Crossover Pipe
1

12590668
Gasket, Coolant Crossover Pipe
1

ph71ss
09-29-2012, 07:14 AM
Well I just asked them for a price So far I have been the only one to diagnose it that is why I am trying to nail it down so if I take it somewhere I know what I'm getting and not being charged for stuff I don't need. They( the dealership) got me a couple of yrs. ago on the brake light problem when they replaced the switch and a day later I had the same problem. Took it back and they claimed the new switch was faulty( doubt it ) since now seeing the info on the cbm plug being corroded being a related problem. Going to either pressure test or dye test it today to try and nail it down. Again, Thanks for the help.

Reg Beckett
10-02-2012, 02:52 PM
I had the same issue on my G6 this spring,just before driving to Arizona.Dealership here said it was head gaskets so went ahead with repair.Mean while my nephew(GM Mechanic at a different dealership)phoned and told about crossover gaskets.Said it was a very common repair on the 3.5 and 3.9 engine.I quickly phoned my dealership but alas was to late,heads were off gaskets were being done.Cost me 2600 canukabucks for repairs.Bad news I'm not sure if I got clipped or not,suspicious but no proof.Good news no more leak,drive AZ was trouble free and the front motor crank seal was replaced as well.So my friend check it out well before hand,keep your costs down

greenman
10-02-2012, 04:30 PM
They( the dealership) got me a couple of yrs. ago on the brake light problem when they replaced the switch and a day later I had the same problem. Took it back and they claimed the new switch was faulty( doubt it ) since now seeing the info on the cbm plug being corroded being a related problem.

The first bulletin was issued June 25 2009. After that point there was no excuse to not attempt the BCM connector fix first.
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Service Information 2009 Pontiac G6 | G6 (VIN Z) Service Manual | Document ID: 2294853
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#08-05-22-009A: Intermittently Brake Lights (Stop Lamps) Do Not Function Correctly, Extended Travel to Shift Out of Park, Cruise Control Inoperative, DTC C0161/C0277 Set (Perform Repair as Outlined) - (Jun 25, 2009)


Subject: Intermittently Brake Lights (Stop Lamps) Do Not Function Correctly, Extended Travel to Shift Out of Park, Cruise Control Inoperative, DTCs C0161/C0277 Set (Perform Repair as Outlined)


Models: 2004-2007 Chevrolet Malibu, Malibu Maxx

2008 Chevrolet Malibu Classic

2005-2009 Pontiac G6

2007-2009 Saturn AURA




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This bulletin is being revised to shorten the required procedure and revise the Warranty Information. Please discard Corporate Bulletin Number 08-05-22-009 (Section 05 - Brakes).


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Condition
Some customers may comment that intermittently the brake lights do not function correctly. Other symptoms may include extended pedal travel required to shift out of PARK, cruise control does not function correctly, and DTC C0161 and/or C0277 may be set.

Cause
The most likely cause of this condition is high resistance due to terminal fretting corrosion in the body control module (BCM) C2 connector (specifically pins C2-18, C2-31 and C2-59).

Correction
DO NOT replace the BCM for this condition. Disconnecting the C2 connector, adding dielectric lubricant and reconnecting the C2 connector per the procedure below will correct the high resistance condition due to terminal fretting corrosion.

Remove the right side front floor console side trim panel to access to the Body Control Module (BCM).
Locate the C2 connector on the BCM.
Unlatch the C2 connector and disconnect the C2 connector from the BCM.
Apply dielectric lubricant (clear gel) GM P/N 12377900 (in Canada, use P/N 10953529), or the equivalent, on the BCM C2 pins (apply with a one-inch nylon bristle brush) on all the C2 connector pins (this will treat the pins against fretting corrosion).
Reconnect the C2 connector back on the BCM and re-latch. Wipe away any access lubricant..
Reinstall the right side front floor console side trim panel.
Using the Tech 2, check that the BPPS ratio is equal to BPPS learned home when the brake pedal is not depressed.
If they are equal, brake lamps should be operating correctly and no further steps are necessary.

If they are not equal, perform the Brake Pedal Position Sensor Calibration procedure in SI to complete the repair.

Check the brake lights for proper operation. If incorrect, refer to SI and perform normal diagnostics.
Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

N9595*
BCM C2 Connector Repair
0.3 hr

* This is a unique labor operation for bulletin use only. It will not be published in the Labor Time Guide.




GM bulletins are intended for use by professional technicians, NOT a ""do-it-yourselfer"". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


2012 General Motors Corporation. All rights reserved.

mrslcom
10-02-2012, 08:08 PM
I had the same issue on my G6 this spring,just before driving to Arizona.Dealership here said it was head gaskets so went ahead with repair.Mean while my nephew(GM Mechanic at a different dealership)phoned and told about crossover gaskets.Said it was a very common repair on the 3.5 and 3.9 engine.I quickly phoned my dealership but alas was to late,heads were off gaskets were being done.Cost me 2600 canukabucks for repairs.Bad news I'm not sure if I got clipped or not,suspicious but no proof.Good news no more leak,drive AZ was trouble free and the front motor crank seal was replaced as well.So my friend check it out well before hand,keep your costs down

Damn, I replaced my head gaskets twice because the stealership said it was leaking. It was slowing losing coolant. That helped a little but I am still losing coolant. I will check the crossover tube gasket next time.

greenman
10-02-2012, 09:16 PM
Going to either pressure test or dye test it today to try and nail it down. Again, Thanks for the help.

I would imagine that shop already put some dye in. You just need a cheap black light.

ph71ss
10-03-2012, 08:54 PM
I had the same issue on my G6 this spring,just before driving to Arizona.Dealership here said it was head gaskets so went ahead with repair.Mean while my nephew(GM Mechanic at a different dealership)phoned and told about crossover gaskets.Said it was a very common repair on the 3.5 and 3.9 engine.I quickly phoned my dealership but alas was to late,heads were off gaskets were being done.Cost me 2600 canukabucks for repairs.Bad news I'm not sure if I got clipped or not,suspicious but no proof.Good news no more leak,drive AZ was trouble free and the front motor crank seal was replaced as well.So my friend check it out well before hand,keep your costs down
Thanks for the info. Finally took it in to the dealership for a diagnosis and they pressure tested the system. They called and said I had a leaking radiator(cost$850) I told them that there had been no evidence of a rad leak and all evidence of the coolant leak was on the sub frame at front(right side) of engine and also on the axle shaft. Also that I could see trace of a line running from the corner of engine where the block meets the head on the rear head right side. They looked again and said no it is the rad. I asked if it was the core or the tank seams and they said they couldn't tell for sure.( how in the hell do you confirm it is a rad leak but you can't tell me what is leaking) Anyway I told them to stop and brought it home. I just pulled the bottom tray off from underneath the rad and there is no evidence of a coolant leak from the rad anywhere. absolutely none.
It is either a head gasket or the crossover tube Gaskets. I guess I'm going to have to keep driving it until it decides to show itself for sure. But I appreciate your response and info

Reg Beckett
10-04-2012, 06:55 PM
when I got mine back after my separation from my 2600 I still had a leak,took it back was told my rad cap (reservoir cap)was not holding pressure,they replaced for 56 bucks,drove to work checked again still leaking.Turned out the hose clamp on the rubber overflow tube was bad.I have no doubt regarding the source of the initial leak being heads or crossover gaskets but the next two trips back caused me to seriously doubt their diagnostics like I say SUSPICIOUS.You don't need to buy a rad and then head gaskets.There must be someone out there that can diagnose your leak.

ph71ss
10-05-2012, 05:33 AM
I've been suspicious of this dealership and the stuff they have told me in the past. That is why I hesitated going there. Anyway, having been a working mechanic in my past life(30 yrs ago) I am not completely stupid with automobiles. I just rented a pressure tester from Advance Auto and will definitely try to find it this weekend after I remove enough engine paraphenalia to see everything I need to see and try and determine the leak. Will update my findings in hopes it will save others some heartache in the future.
Pat

data1701
12-18-2013, 09:25 AM
Did you have any luck diagnosing the leak? I have begun experiencing a coolant smell in the cab on start-up (no moisture on the carpet or on the windows tough) and a few drips on the ground directly below the engine. No moisture is apparent around any hoses or fittingson the top half of the engine where I am able to inspect. I suspect the crossover pipe, but would like to know how to verify.

2006 G6 GT with 3.5L V6 (auto, a/c).

Thanks!

ph71ss
12-20-2013, 06:53 PM
Where I found evidence of the crossover gasket leaking was I had fluid leaking from the point where the block and the rear head meet on the right side of the engine. You will have to be able to get under the car and it is still hard to see it. I never had any fluid hit the ground from that because it ran down on the suspension and burned off on the exhaust pipe. The water pump leak I found was the fluid was running off the bottom of the A/C compressor on the right side front of the engine. Also seen from underneath. Hope this helps you. It is really hard to see anything from above the engine. I found the crossover leak and the water pump leak with a pressure tester rented for free from Advance Auto parts with 15 lbs of pressure. The correct fitting out of the kit for the top of the reservoir on my 2007 was # 25( might save you some time).I would also spray some brakleen or degreaser on the corner of the rear head and block before applying pressure. It will make it easier to see if it is leaking. Good luck, and I will be interested to hear your findings

Jime4247
08-01-2014, 07:07 AM
I realize this is an old thread but I have this same problem. None of my local aouto parts store sell this gasket but I was able to find it online. My question is there 1 gasket required or 2/ From the link to the diagram it looks like each side is a little different so I am curious if both sides are the same and do both sides require a gasket.

This is the one I purchased
http://www.ebay.com/itm/ACDelco-Engine-Coolant-Outlet-Gasket-251-2058-12577704-/261253553808#vi-ilComp

greenman
08-01-2014, 01:25 PM
I realize this is an old thread but I have this same problem. None of my local aouto parts store sell this gasket but I was able to find it online. My question is there 1 gasket required or 2/ From the link to the diagram it looks like each side is a little different so I am curious if both sides are the same and do both sides require a gasket.

This is the one I purchased
http://www.ebay.com/itm/ACDelco-Engine-Coolant-Outlet-Gasket-251-2058-12577704-/261253553808#vi-ilComp

that is the right side gasket, you also need the left side. my local parts guy supplies them in complete kits. i'm sure that same ebay seller has both sides.