Hi everyone,

just recently I’ve have a bad odor of antifreeze when I use heat, so I figured it was the heater core but today I noticed leaking antifreeze from the front of the motor some ware by the water pump. Before I change out the water pump I want to make sure its thats the problem.
Would that cause my recent odor of antifreeze when using heat? Is the leak coming from my water pump? How can I make sure thats where the leak is coming from?

I pulled off the fan shroud, and brush guard and still I can’t see where it’s coming from.

I have a 2002 Zr2 blazer 84k miles, flushed out coolant the summer before last with new 195 thermostat. I’ve had the truck 2 years

thanks for any help

 

Easiest way to check the water pump is to squeeze the radiator hose. If I remember correctly the upper hose should be warm and the lower should be cool. I might have that backwards (do a quick google search). If you have pressure and they are the right temp the water pump is working. If you're worried about a leak then check the fluid level and see if it changes. I have never heard of a water pump causing a smell in the cab. Sounds like you have something else going on. The leak is the part that's throwing me off. I would suggest cleaning around where you think the leak is and monitoring it. You can either use a rag to clean it or wash it with some engine bright and a hose.

 

Have a look at the joint belween the intake manifold & the cylinder heads as these gaskets are known for leaking. Mine has had a slight weep at the join under the A/C compressor for the past 3 years but the leak is so small that i've just left it alone - guess it's a job i'm just gonna have to face one day though? I only put about a quarter pint of coolant in every 8 months or so, it's that small a leak. You could potentially get a smell in the cab even if the leak is under the hood somewhere as the smell can come in through the air intake under the windshield. Hope you get it sorted one way or the other?

 

I get good heat when using heat? It’s not a small leak, I had a decent sized spot under the truck yesterday. I will let it run today and see what it does.

 

I'd bet on the LIM gaskets. An old 96 I used to have did this for a year before it let go completely,at the time I was not aware of the common issue with these motors. One thing that confounds me however is that this is blamed on inferior gasketing between an aluminum intake and cast iron heads. So how come I was able to install aluminum Edelbrocks on early small blocks with no similar failures?

 

I have also heard the problem blamed on using Dexcool but I cannot see it somehow? I would go for the gasket material theory myself. Aluminium & cast iron will expand at different rates but a decent gasket should allow for this. Like I said before, I am dreading the day when my leaks gets worse as i'll HAVE to sort it then. If you look on Youtube search for Blazer lower intake gasket & somewhere on there you will find video of one that leaks so bad that coolant pours out under the A/C compressor almost as fast as the guy can pour it in!
Step66 - I know what you mean about Edelbrocks, I had one of their manifolds on my 1984 350ci Caprice wagon for years & never lost a drop of coolant so I don't see why the 262's should be any different, especially as it's basically the small block with 2 cylinders missing?
We will all be interested to know what the problem turns out to be when you find it?

 

The only experience I've had with these water pumps leaking (both on the 4.3 in the Blazer, and the pump on my 350) is right behind the pulley, where the impeller goes in. When I bought my Blazer, it wouldn't even hold water! I kept hearing water running as I would get the coolant topped up. The skid plate made it hard to tell, but it was coming from behind the pulley.

A few years before, the one on the 350 in my chevelle went the same way, only on the highway at about 60mph! (the only reason I mention that story is the similarity the 4.3 has with a traditional small block Chevy.)

It's tight under the hood of a Blazer, but that's where I would try to check to determine whether or not it's the water pump.

 

My pump was leaking at the axle seal and it was showing at the wheephole on the bottom.
You'll need an inspection mirror to see it.
In the picture the wheephole is at the point of the nail. the pump is seen from the underside.

 

sorry it took so long to reply. But it was leaking out the wheephole, I will change it out tomorrow.
I now it’s a long shot but I was hoping the antifreeze smell would be from a bad waterpump (i hope) and not a bad heatercore... I hate to ask but should I put green stuff back in?

Thanks everyone for the help!!

 

i just went to my mechanic about this today same problem. yes you can use the green stuff it wont hurt it. right now im only using water