Opinion re: head gasket/coolant leak

[greenstarfish20]

Hi everyone-

I'm so grateful to have this resource. I feel somewhat intelligent when talking to mechanics!

I've had an engine light with codes P304/P316 for a while. It starts up rough (VERY shaky a few times with engine light flashing) and then smooths out. Dealer replaced the fuel pump, fuel filter, injector, spark plug. Compression tests and wires have passed. More than once, the dealer said they couldn't duplicate the misfire and that all systems checked. But I'd get home and it would *always* happen to me. Finally I realized that my driving habits (let it sit for several days in between) might be a factor..

Armed with this new information, dealership has decided it's a head gasket causing a slow coolant leak into the cylinder. I actually believe this based on what I've read here. It also explains why it's worse when it's been sitting for a long period, right? I was hoping it was an intake manifold gasket, but I gather (from what dealer says) that it's different on 3rd generation? I don't know about actual coolant loss-- dealership tops it off-- but reservoir was half full when the problem first happened.

So my questions are...
1) is it likely the coolant leak has damaged the engine? I've been driving this way for 3 months. Some long drives in there, lots of short trips. Have never seen the temperature out of range and have never run dry on coolant.

2) if the head gasket is fixed, should I be good to go for a while, or should I be thinking about a new truck? Am I heading down a slippery slope? Would you let your daughter drive it??

 

[97awdx]

Is their a lot white smoke after it sits? If the compression tests are good I doubt its a head gasket, unless you have a super slow leak. Is their coolant in you oil? With that little coolant being used, if it is the head gasket you did not hurt anything. I have seen cars with cranked blocks run for months as log as you keep adding water. Is it a 4.6, V8?

 

[greenstarfish20]

It's the basic 6cyl.

It does blow out a lot of smoke or steam after sitting for several days -- more than is normal, I think. I agree it's weird regarding the compression test passing. When I park it, it is nose down on a fairly steep slant, so that might be aggravating the leak (?) when combined with it sitting for several days.

Not sure about the oil. Truck is at the dealer now so I can't check.

Thanks for your comments- makes me feel hopeful that I've escaped more serious damage.

 

[Texan01]

I had a head gasket develop a slow coolant leak, but would pass a compression test just fine. I finally found it by parking it for a day, then pulling the plugs and then running a compression test again. It was the #6 cylinder that started pumping water after I cranked it.

So it's entirely possible to be a slow leak that develops after it's been ran and then turned off.

 

[greenstarfish20]

Thanks for sharing what happened with yours, Texan. Did you ever see changes in oil/coolant, or would that not be noticeable for such a slooooow leak? I'm guessing it's not obvious, or else my problem probably would have been diagnosed a lot faster.