I replaced the heater core on my 89 s10 Blazer when I bought it back in January. Haven't had a single issue with it, until now... I think. However in the last couple days I've noticed I have a coolant leak forming on the ground coming from the passenger side, right around where the heater core is. I tightened the hoses on the heater core and determined its not that.


Edit: I forgot to mention that this coincides with a cold spell that swept through. Nothing too insane, but far colder than the normal temperatures. down to around 15 degrees or so.

I haven't noticed any coolant on the floor board, and it only seems to leak while it's warming up. After it get ups to temperature I can't see any visible signs on the ground, might just be evaporating from heat before it can make it all the way down I suppose.


Am I SoL and just have to bite the bullet and replace this again or is there some chance it could be something else? I might try some of that coolant stop leak stuff to see what it does, but I've never had luck with it before and I don't suppose I will now.

 

thats pretty much all thats in there to leak is the heatercore. its possible that it could just be a defective one, or there was a bit of water in there when it got cold and cracked. make sure those heaterhoses arent leaking, ive seen it where they will run down the heatercore and make it look like its leaking.

ive put stop leak in cars at work and seen great results i just dont know what the long term effect is on the cooling systems though. its usually people with beaters or car wholesalers taking a car to the auction so rarely ever see the car again

 

They have a special light that some shops have that makes coolant glow fairly bright and allows them to see where it is coming from, I have seen coolant leaks run down wires and make it seem like it is coming from one place when really it is leaking from someplace else. It might be an option if you can t locate the leak. I tend to agree with abig84's diagnosis though, i have replaced heater cores and they had a small crack in the point where the tube goes into the core and it almost closed when warmed up.

 

ive done a heater core, mine the soder joints on the inflow and outflow went, itd make sense to me that a crack could form there and drip weird maybe

 

eh from what ive seen,with me owning many 1st gens, if the cores bad,its going to get on your carpet.

all i can say is drive it a bit,till its completely warm and park it. grab a chair and sit down and see where it leaks...

 

You could get a small piece of pipe the right diameter and disconnect the heater core line then reconnect them to themselves to complete the loop and remove the heater core from the system then look for the leak