I just spent the last week replacing the intake manifold gaskets on my 98 Blazer with 198,000 miles. I was hoping this would fix the dreaded leaking coolant issue, but I just started it up and let it run for 15 minutes in park and not coolant dripping out at a rate of about a drop every 3 seconds. The dripping is coming from near the oil pan, on the passenger side. I don't see anything leaking while under the hood, so I'm assuming its toward the back of the engine.

When I replaced the gaskets, I made sure to clean the mating surfaces and I used silicone in the front and back, so I find it hard to believe it's the manifold. Where else could it be leaking?

I knew this Blazer had a leaking manifold for the last year, but I never had the money to afford the fix. However, I kept water in the radiator and it never even came close to overheating as I only drove it relatively short distances. Is it possible my waiting this long had some effect that I wasn't anticipating, even though I never let it overheat?

One other thing: what it's leaking is NOT green, even though I put in 50/50 that is a green color. What is leaking is CLEAR, but definitely sweet to the taste (I touched the tip of my tongue with a tiny, tiny bit) Does coolant change color? Anyways, I'd appreciate any advice on this. I'm a bit of a novice with engines, and I'm amazed I was able to do this job (replacing the gaskets), and to say that I'm disappointed would be a huge understatement. I'm really hoping the issue isn't something far more serious.

 

Assuming it's not the gaskets you just replaced, maybe you have a bad freeze plug? I've heard them mentioned on here before. Just a shot in the dark, I haven't had to deal with and coolant issues, other than a bad radiator (knock on wood!)

 

When you had the intake manifold off, did you notice any pitting around the coolant ports, (front and rear ports on each side) either in the manifold or the cylinder heads? This link has a couple of images about 3/4 of the way down the page. Don't pay much attention to the procedures involved, as several of them are incorrect. http://www.handymanlyness.com/archiv..._99_Jimmy.html

 

Just curious....what steps are wrong? I have linked this several times because it worked for me.
Are they serious mistakes?

 

There was a very minor amount of pitting on one side, and I covered that area with a layer of high-heat silicone. Otherwise, the mating surfaces were very smooth!

 

Are you 100% sure its not coming from the weep holes from the water pump?

 

Trouble is....coolant is not clear....condensation is clear...well somewhat...but coolant is not....unless only water is used without any antifreeze mixed in.

Condensation will drip out of the exhaust systems for the first few minutes after starting a cold engine. Is it possible that this is what you are seeing? Try putting a paper towel under the drip to ensure that there is no color present.

Fuel is somewhat clear....power steering and brake fluid are again somewhat clear when new/fresh...but I have never seen any clear coolant.

Oh and good job on changing out the intake gaskets. I did this task a short time ago and lots of chances to create major problems....GOOD JOB!!

 

I'm not sure if it's the water pump or, as a friend suggested, the heater core. Last night I let it run in my garage for about 20 minutes, and there was no heat out of the vents. Also, the temperature gauge never moved once. For a second I started wondering if I did something REALLY stupid like install my new thermostat upside down, but then I remembered that there because of the size of the springs on the bottom and the lack of height in the hose, it would've been impossible.

Regarding the unknown liquid. One thing I should mention is that before I did this job, I had straight water running through the cooling system because to replace coolant on a near daily basis would have cost an arm and a leg. Before I tore into the manifold, I did drain the radiator, although I noticed a small amount of water in the reservoir. After the job, I put nearly a full gallon of premixed coolant in the radiator, and after the engine was warm, I topped off the reservoir to the HOT FULL line. If this thing is really leaking from the manifold, reservoir, or one of those hoses, it should be GREEN. But its absolutely clear on a white paper towel. However, it definitely has a super-bitter, citrus-like sweet taste to it, and it tastes just like the 50/50 I put in.

At this point I'm about to take it to a shop and have them diagnose it for me.

 

If it was the water pump you would be able to put a finger on the underside of the bearing and find coolant. If the water pump gaskets are leaking...a lot more trouble to get a finger wiped around the pump to block interface....but possible...and of course the coolant will find a path other than stright down.

If the heater core was leaking I would think you would have a wet spot in the passenger side footwell. Not having any heat could be the heater core is plugged or the HVAC temp door is stuck to the cold side....this is a totaly different problem.

Did you check both heater core hoses to see if they were both hot or just one? Easy to flush the core...just use a garden hose and go very easy on the pressure/flow, just want to flush the core, not pressre test it.

Is there an AutoZone near you that you could rent a coolant system pressure tester? I have never used one, so I am no help with this.

Keep after it.

 

I discovered one issue. The temperature gauge has not moved since I finished the gasket fix. I discovered there's a broken connector on a sensor in the block, which I've found to be the coolant temperature sensor. The wire and connector are fine...luckily the break was on the actual sensor, so I will need to replace this (also explains why I have a Check Engine Light).

Also, I'm now starting to get heat in the interior. No puddles of coolant on the passenger floor board. However, now I'm starting to notice that the previously clear fluid is turning green, so I'm definitely leaking coolant from somewhere. I'm going to take it to a buddy's who is going to help me replace the sensor. He's got ramps and is going to help me locate the leak.