Would this give me a rough idle? I just replace a lot of things on this car, LIM gasket and all the goodies associated with that, and I am going to replace the O2 sensor tonight but I pulled the wire off of the coil and noticed this(see picture) it was the only one that was different colored. I cleaned it off and have not had a chance to drive it yet. Also, on a slightly different path, if you overfill the coolant reservoir, will it leak all over the ground? Please tell me that is my problem. When I replaced the LIM gasket, of course I drained everything, then refilled the most I could. I drove it a couple of days and filled the radiator all the way up and the reservoir to the line. It has been so crappy here in Nebraska weather wise that I have not had a chance to crawl under it to see where it is coming from. The radiator is still full, but the reservoir is low again. I do not see any leaking around the LIM gasket or anywhere up above. Any ideas are appreciated!!

I would say good chance on the rough idle.

Secondly, i'm in the same boat you are as far as leaking coolant. I just had my LIM replaced not too long ago and also just had the Dex flushed out and replaced with universal, and then i had a new thermostat put in. It appears i'm leaking coolant because i've had to fill my overflow a few times already. I took the car to Pep Boys 2 times now and they did the cooling system test where they put dye in the cooling system to see where it'* leaking from. They also do a pressure test and they even did an exhaust test to see if coolant was getting into the exhaust. They found absolutely nothing after 3 hours of testing all this. And they said the engine was dry and no coolant leaks could be found.

So...........i'm going to assume that these are air bubbles that are being released and making the coolant go down. May be what our problem is? I hope so....

Yeah, except I had a big puddle under the car just the other day. I noticed it in the snow. I was not too pleased. Of course everthing is wet underneath with the snow so I cannot tell where it is coming from. I know not from the gaskets because they are all dry.

Out of the 6 3800 engines that I work on, 5 of them had one coil post that was rusted like that. Cleaning them helps for a while, but it seems to often come back. I'd check the condition of the plug wire that attaches to that coil tower, also.

Were the coolant elbows replaced when the intakes were done? What'* the condition of the radiator cap?

The coolant elbows were replaced. The cap is not in the greatest condition, it seems tought to get off. It is almost 'corroded'. Again, the radiator is full, all the way to the cap. The antifreeze is just above the port coming in to the reservoir. Not really sure right now (?)

What area of the car is the puddle under? Is it up near the radiator, or closer to the location of the coolant expansion tank? The cap on my car was bad when I was loosing coolant. We've also had some issues show up with some of the replacement coolant elbows.

The coolant was right in the middle of the car. But....I changed the O2 sensor last night about an 2 hours after my wife had gotten home from driving the car all day and the coolant level in the tank was the same as before. Did I possibly put too much in there at first? I will keep checking it but hopefully it is done leaking. I want to start modifying this car not continue to mess around with other things.

To burp the air from the heater after a car has been drained and refilled, my manuals say to have the car completely heated up--the lower radiator hose is hot. That means the radiator has hot water returning to the motor and the thermostate is open letting air out along with water. Run the motor to 2500 or 3000 rpm for a few seconds at a time and do that 5 times.

I position the car with the radiator uphill in my driveway which has a sllight slope up toward the garage; that makes it easier for the air to leave the heater because the heater is lower than normal. After that then open the bleeder screw on top of the thermostate housing cafefully until water runs out to purge air trapped there. I use a towel around the screwdriver in case water and air might spurt out--it never has.

Then after the car cools I check the radiator to be sure it is full. check level in reservoir and I'm done.

One potential for water loss might be a water pump. That'* hard to find without a mirror.