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Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 10:56 pm
by 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?
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 10:59 pm
by harofreak00
Can you post a video?
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:20 pm
by 00Beast
I hate to say this, but it sounds like a bad head-gasket.....
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:22 pm
by Trums2
video of what?
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:23 pm
by 00Beast
Video of the engine running.
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:23 pm
by 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?
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:27 pm
by 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?
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:40 pm
by 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.
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:44 pm
by Trums2
Headgasket really bad? or something else?
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Nov 20, 2010 11:57 pm
by 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.
Re: Overheated - shut off - runs like junk at idle
Posted: Sun Nov 21, 2010 12:00 am
by Trums2
Ok, i will get pics of the plugs i just removed then the plugs I just put it. Tomorrow
Re: Overheated - shut off - runs like junk at idle
Posted: Sat Jan 08, 2011 4:24 pm
by Trums2
It turned out to be a blown headgasket and cracked head dumpin water directly into the cylander.
Re: Overheated - shut off - runs like junk at idle
Posted: Mon Jan 10, 2011 1:59 am
by 2000GreySSEi
Ouch that's rare to hear these happen to 3800 engine. Did you find the culprit to it overheating?
Re: Overheated - shut off - runs like junk at idle
Posted: Mon Jan 10, 2011 8:42 am
by 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.