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Radiator Leaking after Heater Core replacement

2K views 23 replies 8 participants last post by  fishnyc22 
#1 ·
Hey there Jeepfolk.

In the fall I replaced my heater core (not fun) in my 2005 TJ. All looked good except I recently noticed that maple syrup smell again (this time outside the car). Looking under the hood it seems the radiator is leaking (typical signs of coolant in the seams at the top and bottom). So I"m going to swap it out for an OEM radiator. While I'm in there I'm going to replace the water pump and thermostat since I believe they are original as well. Looks like a fun project (more fun than the heater core for sure).

Anyway a few questions I was hoping you can help me with.

Can I reuse the coolant in the system when I drain it to replace the radiator? I only put it in like 4 months ago.

When I replaced the core, I flushed the system with distilled water. I was wondering if when I did that...when drained the water and filled it with 50/50 coolant in I needed to account for some water that remained in the system. Is it possible the water/coolant ratio was off because of that water in the system and I possibly had a freezing issue in the radiator? I live in a high altitude town in Colorado (near Black Bear Pass in Telluride), while it's been an unfortunately mild winter, it still gets very cold at night (though jeep is garaged). Should I have not used 50/50?

When I replaced the heater core, I cleaned the box really well, but when I run the heat there is still a faint smell of coolant coming from the ducts which is annoying (it may be getting better over time I think)? Is it possible there's remnant of the coolant mist that the leaked core created in the ducts? Can/should I clean the ducts some how?

Stupid blower fan squeaks when I have it on the lower speed setting (never did that before I replaced the core). Yes I know I should have replaced the blower too but I was trying to be economical about the whole thing. Its tolerable but wondering if its possible to do anything to fix that squeak without pulling the whole thing out again (not happening).

Anyway. Just some things I've been wondering. Any help is appreciated.

- Fish
 
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#3 ·
Stupid blower fan squeaks when I have it on the lower speed setting (never did that before I replaced the core). Yes I know I should have replaced the blower too but I was trying to be economical about the whole thing. Its tolerable but wondering if its possible to do anything to fix that squeak without pulling the whole thing out again (not happening).
You don't need to remove anything to replace the blower in your 2005 (well, maybe the glovebox door, but that's easy). Just look up under the glovebox, and you'll see it on the right. There's a tab you pull down gently on, rotate it counterclockwise, and it pulls down. Spend a few minutes under there with a flashlight and you'll figure it out.
 
#4 ·
I did chuckle a bit when you were describing your town -- maybe it's just me, but I kinda figure you'll have a pretty hard time finding folks in this forum that don't know where Telluride is. :smile2:

If you're dead set on trying to reuse the coolant, I'd say you can likely get away with doing so provided you drain it into a clean container... might want to pour it through a very fine mesh filter as well to ensure any particle contaminants are removed as well. Personally I'd be inclined to just splurge a bit and get new coolant. In the future if you're concerned that any captured distilled water might adversely affect the coolant mixture, you should just go ahead and check it using a common tester available at any FLAPS.
 
#7 ·
I did chuckle a bit when you were describing your town -- maybe it's just me, but I kinda figure you'll have a pretty hard time finding folks in this forum that don't know where Telluride is. :smile2:
I figured. If you've never jeeped around here you should make a trip. It's pretty incredible. I just got my TJ a year ago. Been over a few passes but don't trust it or myself to go down Black Bear. :surprise: I've been down in a friends jeep. It's crazy.

If you're dead set on trying to reuse the coolant, I'd say you can likely get away with doing so provided you drain it into a clean container... might want to pour it through a very fine mesh filter as well to ensure any particle contaminants are removed as well. Personally I'd be inclined to just splurge a bit and get new coolant. In the future if you're concerned that any captured distilled water might adversely affect the coolant mixture, you should just go ahead and check it using a common tester available at any FLAPS.
You're right. I'll just buy some more. It's not a huge expense in the grand scheme of things. Thanks for the reply.
 
#12 ·
I watched a video on YT where the guy put RTV on one side of the gasket so it stuck to the water pump. But he didn't put it on the other side that goes onto the engine. Is that right? also should I use RTV on the thermostat gasket as well?

thanks!
My understanding is that RTV is not needed. The guy in the video used it to keep the gasket in place, not to seal it. The gasket alone works well to seal it, but only if it's in the right spot, and it can shift easily during installation.
 
#13 ·
I watched a video on YT where the guy put RTV on one side of the gasket so it stuck to the water pump. But he didn't put it on the other side that goes onto the engine. Is that right? also should I use RTV on the thermostat gasket as well?

thanks!
You don't need RTV for the T-stat. Just get a new gasket. Be sure that the mating surfaces are super clean of any and all residue, or it will leak. I used some extra fine emery cloth on mine when I did it last fall. Also a tip mrblaine passed down to me that I will share with you. When installing your new T-stat, use a very small amount of grease on the backside of the stat flange to hold the stat in place while putting the cover back on it so it doesn't drop or shift. OEM parts strongly recommended.

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#15 ·
I just replaced the thermostat housing on my 2004 and it leaked from the lower bolt. When I took it apart I found the hole is drilled through to the cooling passage behind the thermostat and without sealant it was leaking. Maybe new it didn't do that but it sure does now. Obviously other people have better luck than I do or possibly others aren't drilled through? While I agree the gasket doesn't need RTV, my bolt sure did.

I just did my radiator and all the hoses too, was easy, I'd say much less hassle than a heater core.
 
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