I have been fighting coolant problems from every part. In the past I have replaced the radiator heater core thermostat and various other coolant pieces. I went out to my blazer today to get something from the back. I noticed a leak underneath. Was wondering where it could be coming from. The weird thing is the car hasn't been run since about 12 hours ago.

 

That's a typical place for a leaky lower intake manifold gasket to drip. A pressure test would help with diagnosis, and you'll probably need a small mirror to check the back of the engine. If that's what's leaking, insist on a Felpro gasket MS98002T. Time consuming, but not a difficult job to replace it. Plan on 8 hours if you're not familiar with replacement. We can help you, as there are several do's & don'ts that will make the job easier, and with fewer headaches.

 

Where would I go to find the do's and donts

 

Like said Captain Hook said its a upper intake manifold leak.Its common for them to leak on the back and notorious problem on this engine.It was not just common on the V6 vortec but the V-8 also.There were numerous GM service bullitens about this problem but no recalls

 

DO'S:
The absolute best information can be found in a GM "dealer issue" shop manual. Ebay usually has used sets, (typically 3 volumes) at reasonable prices. They are year specific, so make sure you get the correct set for your vehicle. The gasket set, as mentioned above, is made by Felpro, part # MS98002T, available on Ebay, Amazon, Rock auto, etc and local auto parts stores. Clean up and prep work is extremely important. Intake bolt replacement is not necessary if you chase the threads in the heads, and on the bolts, with a tap & die. Thread sealer MUST be used. Accurate torque wrenches, both inch pound and foot pound, are mandatory. A scan tool capable of viewing camshaft retard is mandatory to adjust the distributor upon completion. Before you remove the distributor, let us know and we can explain how to do it, and save you a big headache.


DON'T use Chilton/Haynes manuals, or information found on websites or Youtube. There is a lot of misinformation out there If you have a question, ask us here on the forum. DO NOT use a wire brush or abrasive materials, (sandpaper, abrasive discs etc) for cleaning old gaskets off.

 

I see that you are talking about scanning the camshaft for the distributor. You said you could help I would like to know. Going to change out the gasket this weekend.

 

As mentioned above: The absolute best information can be found in a GM "dealer issue" shop manual. I'm assuming you have one now. If you still have questions while following the steps in the manual, let us know.

 

I think I'm having the same problem with my 99 2wd 4dr. Got it for free from a friend that didnt want to f with replacing the fuel pump when it went out @ 270K. Long trip in NM, water pump went out on the side of the interstate, when it overheated cracked the radiator. Replaced the fuel pump and limped to a friend's house, nursing coolant back into it every 30-45 miles. Replaced the cracked radiator and drove home 80 miles no issues, parked it overnight. Then 10 miles from home toward work today, overheats, spraying steam from the backside of the engine. pulled over and waited for 40 minutes for a friend to come with water, filled up the radiator. It took a gallon and a half, then water started running out of the back of the engine area, driver's side of halfway with the engine off. Lower intake manifold gasket leak? Or something else before I get set up for the wrong thing...