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My son just bought first car and immediately white smoke came out of hood on passenger side. Research shows this 3.4 engine had dex antifreeze issues causing blown head gaskets and intake manifold issues and causing cars to over-heat.

We noticed clean oil-but saw *sludge in the top of radiator neck-We were attempting to see if any bubles would develop indicating a blown head gasket BUT what happened didn't allow us to finish because of quest.1

1. the Rad fluid was all the way to the top and with a cold start, liquid poured out on the ground. So we never got to a warming point to verify any bubbles. Where should we begin to look for what is blocking flow.

2. There was a new water pump put on the mechanic tells us and they flushed the coolant system out-if somehting was done incorrectly , where should we look on why coolant isn't flowing.

3. Can you tell me the basic coolant flow this engine goes from beginning to end and in what order of operation to ck it. and do you know where we might find a detailed diagram to pursue a DIY.

Thank you in advance.

Drosencrans, Was it smoke or

Submitted by drivability on Mon, 09/26/2011 - 14:33.

Drosencrans,

Was it smoke or was it steam?

Where was it coming from?

Is the engine actually overheating?

You mentioned the "dex issues". That would be an understatement. It's been said that there are two kinds of 3.4l intake gaskets. Those that are leaking and those that have just been replaced. They have atleast improved their intake gasket with an updated design.

You mentioned the "sludge". This is not uncommon and is usually caused by a lack of cooling system maintenance. Quite frankly I feel that their 5yr/150k mi. (or whatever they're claiming now) life on the dexcool product is a joke. When the dexcool product congeals there is usually very little that can be done to cost effectively unclog a radiator.

Based on your description the first things I would check are proper thermostat operation and radiator flow. I would also pressure test the system and check for proper cooling fan operation.

You asked about the coolant flow. This is the same as almost any other automobile engine. In a nutshell...It is pumped into the motor. It heats up. The thermostat opens. The coolant is pumped into the radiator to be cooled off and the process starts all over again.

Post back with more info/questions or if you need help performing the tests. Thanks.

I'm not sure if it was smoke

Submitted by drosencrans on Mon, 09/26/2011 - 15:04.

I'm not sure if it was smoke or steam, usually it is a "plume" that lasts for about 1 or 2 seconds this usually happens within the first 10 minutes of running and you can smell coolant really strong. the "plume" comes from the back of the engine and in the middle or towards the drivers side.I've never seen the cooling fans come on and I've never seen the temp go above 1/2 -3/4.I am just sure that something serious may be wrong. there is NO white smoke in the exhaust so far and I think there may be coolant leaking from the same area the "plume" comes from if that is possible. when we rev the engine we can heat up the engine but it never got hot I'll try turning the AC to confirm the fans work. also only on occasion when we rev the engine it will sort of sputter or surge in rpm.

Drosencrans, When engine

Submitted by Big Block 409 on Mon, 09/26/2011 - 15:39.

Drosencrans,

When engine coolant is forced out of the exhaust system it is usually heated by the hot exhaust manifold and the rest of the exhaust system. This will result in a sweet smelling steam leaving the tailpipe. The steam is persistent. It will hover in the air and not dissipate like the normal steam that comes from the combustion process. The first check is to see if combustion gasses are present in the cooling system. Take a sample of engine coolant to a local radiator shop and have it analyzed for the presence of hydrocarbons. You can also buy a (BLOCK TESTER KIT) from an auto parts store and do the test for combustion gasses yourself. Another check is to look at the oil after the engine has thoroughly warmed up. If antifreeze is mixed in with the oil, both will whip up into a frothy brown mixture that looks like a milk chocolate milk shake. If it looks like chocolate mousse you most likely have a blown head gasket. Another check (done with the engine cold) is to fill the cooling system to the top and remove the radiator cap. Now start the engine and race it. If there is a compression leak and gasses are going into the cooling jacket then the gasses will displace the coolant. Since the cap is off the coolant will be pushed out of the radiator. At that point you most likely have a blown head gasket. Another check is to remove all the spark plugs. Using a cooling system pressure tester pressurize the cooling system to 20 PSI. Leave the system pressurized for several hours. Now lay down some clean paper towel along the cylinder heads at the spark plug wells. Crank the engine over for a few seconds. Since the spark plugs are out any antifreeze that has leaked into the cylinder will be blown out onto the paper towels. Examine the paper towels for signs of antifreeze. This method also helps you to determine which is guilty cylinder or cylinders. Looking at the condition of the spark plugs can also help you to determine if there is a blown head gasket. You can suspect any plug that looks different from the rest. By the same token if you can see antifreeze on a plug then you know that is the bad plug. Also if a plug looks cleaner than the rest, or has a white powder on it then you can suspect that one as well. Post the results of all the tests you do.