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99 Blazer Coolant Leak!!


FireDude312
12-09-2009, 09:57 AM
Looking for some guidance here...I'm not sure where to go from here!

For about a year now, my 99 Chevy s10 blazer has had a slow coolant leak. I would top off the reservoir every couple weeks. Within the last 2 months, it has progressively gotten worse.

My pop has a pit in the garage, so I went underneath to check it out. The bottom front is covered underneath with green anti freeze. It looks like it's leaking from somewhere, and then just blowing from the air all over.

I used a flash light, and there are no obvious spot's where it would be leaking. At first it looked like it might be leaking from the Thermostat gasket, so I changed it, but that must not have been the place. It's still leaking somewhere low towards the front of the engine.

One big point... it only leaks faster, and heavier when my heater is on! Any idea's guys? :banghead:

No..there is no excessive white smoke, or anything from the tail pipe.

MT-2500
12-09-2009, 10:03 AM
Looking for some guidance here...I'm not sure where to go from here!

For about a year now, my 99 Chevy s10 blazer has had a slow coolant leak. I would top off the reservoir every couple weeks. Within the last 2 months, it has progressively gotten worse.

My pop has a pit in the garage, so I went underneath to check it out. The bottom front is covered underneath with green anti freeze. It looks like it's leaking from somewhere, and then just blowing from the air all over.

I used a flash light, and there are no obvious spot's where it would be leaking. At first it looked like it might be leaking from the Thermostat gasket, so I changed it, but that must not have been the place. It's still leaking somewhere low towards the front of the engine.

One big point... it only leaks faster, and heavier when my heater is on! Any idea's guys? :banghead:

No..there is no excessive white smoke, or anything from the tail pipe.

For them hard to find leaks they make a coolant dye to put in coolant.

Clean off old leakage and add dye and start looking for leak.
Check cold and warm and hot.
Also a rad pressure tester helps find leak.
And watch rad cores for leakge.

Post back what you find.

FireDude312
12-09-2009, 10:12 AM
hmmmm....

But this DOES NOT sound like the lower intake gasket though right? I've read other threads on here about disappearing coolant, and it doesn't seem to me like it would be that...especially considering the entire bottom is soaked.

MT-2500
12-09-2009, 12:41 PM
Could be or could not be.
I have saw a lot of lower intakes keak at front of engine.

Test it as posted in post 2 and see where it is leaking.
Let us know what you find.

old_master
12-09-2009, 05:55 PM
Possibly the water pump is what's leaking. 1999 came from the factory with Dexcool coolant which is orange in color, you mentioned green was leaking out. This article talks about using ethylene glycol, (green coolant) in a vehicle that was designed for Dexcool.

http://www.ricksfreeautorepairadvice.com/repair-topics/cooling-system-service/water-pump-analysis%E2%80%94what-happens-when-you-use-the-wrong-coolant

FireDude312
12-12-2009, 12:53 PM
I didn't get to pressure test the system yet, but I have confirmed...it ONLY leaks when the heater is turned on.

If I crank the heat, and the motor is warm, is starts pissing out from somewhere. It also somehow makes its way the whole way back around the transmission case, and drips onto the exhaust, which causes a show. Embarrassing.

The entire bottom front end is soaked with the new green coolant I just refilled it with. After a fire call this morning, I refilled the reservoir, and drove to dad's with the heater on. When I got there, the reservoir was 3/4 empty, and everything underneath was soaked. I left and came home without the heat on, and now it's not leaking. Something with the heater core maybe? The inside passenger area is dry though.

Hmm... I'll try and do the pressure test today.

old_master
12-12-2009, 01:01 PM
When the heater core leaks, the carpet on the passenger side under the dash gets soaked. Leaking only when the heater is on is a coincidence, guaranteed. Most likely why it stopped leaking is because the coolant level is low. Possibly the intake manifold gaskets are leaking, very common problem. Fill the system and pressure test it, you'll find the leak. Repair it and then completely flush the cooling system to remove all traces of the ethylene glycol and refill with Dexcool.

b1lk1
12-12-2009, 01:41 PM
An improperly maintained cooling system on these trucks will result in multiple parts failures. I'd be surprised if the wrong coolant took out the water pump, but it would NOT surprise me if it took out the radiator, intake gaskets and heater core. This happened on my Jimmy since the coolant was never serviced before I got it and basically I got to change all three of those parts in a 6 month span.

4x4 blazerguy
12-13-2009, 12:31 AM
Did Dex-Kool get used from 99 & Up? I'm kind of looking for a new Blazer & this was good info for me, Because this is a major issue to check before considering a newer Blazer.

old_master
12-13-2009, 01:18 AM
1996 and newer use Dexcool. Provided the system is maintained correctly, it's fine. If ethylene glycol is ever added to the system, you'll have expensive ongoing problems, guaranteed. Click on the link in post #5.

FireDude312
12-14-2009, 11:12 PM
drum roll........

Ready for the answer to the problem?

I dropped it off at my garage today. They called me back within 2 hours, and gave me the bad news.

He said they pressurized the cooling system, and once it was up to pressure, it started pissing out around the intake manifold gasket.

Estimated bill.... $650 - $700.

:shakehead:frown:

MT-2500
12-15-2009, 08:29 AM
Yes proper testing gives the answer.

Your estimate sounds like on high side.
But.
We do not know there labor rate and what all they are figuring with the repair?

I would ask them to break it down parts and labor.
Labor flat rate is around 5 hrs.

And be sure they are using the Fel-Pro Type Hard Rubber PROBLEM SOLVER INTAKE GASKET.
Good Luck

b1lk1
12-15-2009, 08:37 AM
Be lucky you're not in Canada. Average price for that job is over $1K up here.

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