Overheating/ Help? Suggestions?
 

2001 Alero, 3.4 6 cyl. 210,000 miles. A few times over the past few weeks, the temperature gauge went a little above halfway and then dropped back down to normal. Then last week the car started overheating. I thought I had the solution, as I had the same problem both 10 and 5 years ago, which was solved with a new temperature sensor and thermostat respectively. I replaced both this time, BUT as I poured new coolant into the reservoir (with the car off) I noticed it spilling down onto the ground, originating from somewhere near the thermostat housing (but not from the thermostat housing- that's dry). So, I'm guessing I have a crack in my engine block in some inaccessible place that I wouldn't even be able to see unless I lift out the engine. Or could it be a bad head gasket? In either case I'm guessing that would indicate a very expensive and/or futile problem, eh?

Have you checked the freeze plugs or the drain plug on the engine block?

could be a wicked bad lower intake gasket leak. or a bad hose. cracked heads and blocks arent very common on that engine.

Yeah I say limg. Mine leaked out there when I had it bad. You may as well do head gaskets to since you overheated and theres a good chance they're bad. You might have warped your heads or cracked them so get em checked out also.

So the consensus seems to be the LIM or the freeze plugs. Sounds like a time-consuming and expensive chore.

Someone else mentioned the freeze plugs to me. I hate to sound incredibly ignorant, but what are they exactly and where are they located?

What they are is roughly quarter sized metal plugs which are on the heads and block, and what they do is: in the event of a freeze over of the water in the water jacket, they pop out, which relieves pressure on the heads or block and prevents major damage to the engine.
Some are bigger than a quarter, some smaller. On average, they are about that big.

If you are good at it.... 4-6 hours for LIMG. Its not a terrible job. Just time consuming and you have to be careful in some areas. My first time doing it, it was about 7 hours for me without including all the smoke breaks and pauses for bitching haha.

First time... was being cautious and taking it slow. I was in no rush.

I helped a friend with a LIMG on his 94 Buick Century custom (3100). Took us a total of about 8 hours, but that was the first time he had ever taken engine repair or maintenance further than spark plugs.
It wound up taking 2 days, because we would take one thing off, and it needed to be replaced. Take another thing off? Yep, replace it. Actual work time, barring a lunch break, 8 hours.

I did head gaskets in mine in 7 hours. :)

I am curious as to if the OP still has the original LIM gasket on the car. Nobody asked that yet. Just checking.

Sounds like it's leaking from the valley between the lower intake and block.

The solution
 

With the help of my father-in-law, we tore it apart and, yes, it turned out to be the lower intake manifold gasket. It looked as bad as the one in the picture here: http://troubleshootmyvehicle.com/gm/...intake-gaskets

how did the oil look ?

Well, the oil_looked_ok but there was definitely coolant in it. When we looked at the dipstick the level was about a quart over full and I know I didn't put that much oil in. Also, we loosened the oil pan drain plug enough (without taking it off) so that fluid started dripping out and we saw that it was definitely coolant and not oil. We did change the front head gasket just in case. I guess we should have changed the back one too but there was no chance the leak was coming from there, and we were racing against time.