Overheated - shut off - runs like junk at idle

[Trums2]

The other day the car overheated and shut itself off. Once it restarted it ran real rough. I figured it was left over from the heat. The next day it still ran rough and threw an engine code. The codes stated there was a misfire and a knock sensor issue. The misfire turned out to be #3 pinched on itself, then I found #4 was partially broken. I replaced all 6 plugs and wires but it still idles like junk and at 4 grand it knocks and losses power. Any suggestions?

[harofreak00]

Can you post a video?

[00Beast]

I hate to say this, but it sounds like a bad head-gasket.....

[Trums2]

video of what?

[00Beast]

Video of the engine running.

[harofreak00]

The engine running when its knocking and losing power.

3800's aren't normally known to blow head gaskets, except for when they are overheated. If it was so hot that it shut off, that's not a good sign. Any bubbles in the coolant reservoir tank?

[Trums2]

I can post a video tomorrow - a bit late to run it tonight. When I rev it in park I don't seem to get the same engine response as I do when it's under load. When it idles it does shake alot, and I don't seem to hear any knock but the engine light is on steady. When it's under load and the RPMS go over 1500 the light begins to flash and then when they go below 1G it goes steady again.

Don't have any bubbles but do have a water leak that I will fix tomorrow and that may then change.

Is there a way to test the head gasket?

Is it possible that it's a bad knock sensor?

[00Beast]

You'll have to do a compression test to test the HG. The SES light flashing indicates a misfire. That it's constantly over 1500 RPM is really bad.

[Trums2]

Headgasket really bad? or something else?

[00Beast]

Something really bad. First step will be to inspect the spark plugs. Pull all the plugs, keep them in order and snap a picture of the electrodes. Post it here, and we can help diagnose what could be wrong. Also, get the codes pulled.

[Trums2]

Ok, i will get pics of the plugs i just removed then the plugs I just put it. Tomorrow

[Trums2]

It turned out to be a blown headgasket and cracked head dumpin water directly into the cylander.

[2000GreySSEi]

Ouch that's rare to hear these happen to 3800 engine. Did you find the culprit to it overheating?

[willwren]

What we have here isn't really a head gasket failure. It's a cracked head. The gasket was the victim, not the culprit. That's a serious overheat job, and I suspect the cracked head won't be the last thing you find wrong with that motor. You seriously stressed every internal part of that engine.