Hello all and thanks in advance, I have a 1998 Dodge Avenger 2.5L V6 and I think I have a blown head gasket. My Avenger pushes antifreeze into the overflow bottle and it spills out to the growned. My dealer said a blown head gasket is the only thing that would cause that to happen. I aked them to test the gasket and they said you cant really test the gasket. Anyway I have changed it all from the radiator to the water pump. It only does it once and a while maybe like once every two weeks. Any ideas PLEASE?

 

There really isn't a good way to test for a blown head gasket , OR a cracked head ....
Things to look for are bubbles in the radiator cap
You can also check the compression of each cylinder, it might indicate a leak ...
Being intermittant like it is that might be very hard to catch ...

 

A blown head gasket won't cause your coolant reservoir to overflow without signs of anything else reminiscent of a blown head gasket. If your head gasket was blown, you would have a mixing of oil and coolant, which you will find in their respective areas. You would also be blowing out white/blue smoke from the exhaust and your car would run poorly.

A blockage will cause your issue or a coolant temp sensor that is getting ready to die on you. You may need to change the thermostat and/or coolant temp sensor.

One good thing to do is to watch your coolant rise (from the fill neck). What you want to look for is constant flow of coolant. Keep an eye out for air pockets or bubbles.

Have you always put the green coolant in? Do you use water, premixed bottles, or do you mix it up yourself?

When you say you've changed it "all" what does that entail? Your definition of all may not be the same as mine.

 

A 20 year mechanic at the dodge dealership told me that the only thing that would cause antifreeze to be pushed out of the radiatore into the resavior is a head gasket on its way out. I have no smoke coming from the tail pipes and no mixing of oil and antifreeze. I have already changed the thermostat, radiatore and cap, ac condenser, both fans, water pump timing belt ect. have not done the temp sensore but dont see why or how that would effect the flow of the antifreeze(please explain) I dont know what the dealership has done but they flushed and filled my car so I assum they used the right stuff. THANKS

 

Yes, but the keyword being "dealer." Not all are created equal, but most have filled in the circle next to "shady."

Under certain circumstances, I suppose pressure from one side of the gasket can push in one direction only and going out can be one of them....however, for you to be lucky enough to experience it without the other symptoms of a wearing gasket is too incredible to believe.

Tell me this, when you see coolant flowing out of the reservoir, do you refill it? For all you know, the coolant could be overflowing because of the system being over filled. That is another job of the reservoir...to spew out any over fill.
Do you overheat?
Do this, the next time your coolant overflows, don't refill it. Why? Because there is only a certain amount of coolant the system can have in it at any time. If you keep filling it back up, it's normal for the reservoir to keep spitting it out.
Anyway, keep an eye on the temp gauge and keep a bottle of antifreeze in the trunk. This may be an inconvenience, but it's less of an inconvenience compared to the price of the labor involved with replacing a head gasket from the dealership. Once you get to your destination (the next time out and about) and the motor has cooled off or before you head back out again, look at the reservoir bottle. It should be at the "Max" line or between it and the "Low" line. The do it again at the next destination, keeping note of whether the bottle spews out coolant or not.
This will eliminate the simple fact that the cooling system is doing what it should be doing.

So, do you refill the bottle or the radiator when you see coolant spilling out of the bottle?

 

U are right it could be just me overfilling it, so what im doing know is im just going to let the overflow do its thing and see if it overheats. It hasnt over heated since I put a new fan on it as the old one went bad. And what i did the last time it overflowed I said the hell with it and left it alone, it was filled to the top of the overflow. Then I checked it a couple of days later and it was back to normal level. But was that because it spewed more out or did it suck some back in? I dont know. Your last question. I just take the overflow bottle off and pour it back into the radiator. I really appreciate the help and thank you I will get back to the forum as soon as I have any new developements. Again thanks

 

That could be it then. Filling it to the top will cause it to spill out once the motor has been ran enough to warm it up. If the motor needs more, it will suck some up from the reservoir and siphon back any extra once the motor is turned off. If the bottle was filled to the top, it will spill out because the motor will send some to the reservoir naturally due to expansion of pressures from the hot motor.
The reservoir should be anywhere between the low and full marks on the bottle. If you're not overheating and the level of the coolant in the reservoir is between those two marks, I'd say you're good to go. But give us a follow-up when you get a chance. I'd say wait a week if you can to be sure, but keep monitoring the reservoir all throughout.

 

My daughter has a '98 Avenger ES with the 2.5. She has been over heating as of late (the temp will be normal then peg to H after 15 minutes). The car is now parked. We replaced teh thermostat 2 years ago. There is no collant and oil mixing, and no evidence of coolant in the exhaust. I don't see a pulley failing on the water pump. Could the gasket be going and pushing hot exhaust into the water jackets causing this to over heat and "boil". The coolant (mostly water) in the bottle was so hot it was boiling. I had the heat on while driving and the air was so hot it almost burned my legs. I've heard anything from water pump, head gaskets, thermostat to temperature sensor... Your thoughts??

 

Replace the thermostat AND radiator cap first ...
Do the electric fans kick on ?
One kicks on with just the heat , and the other kicks on with temp and A/C on

 

Yes, the theromstat was replaced 2 years ago, the radiator cap 4 months ago. The first fan kicks in after 15 minutes of running and the second fan kicks in as the temperature gets close to the "H"... Your thoughts?