Tahoe Leaking Coolant


  1. Conlan Rose

    Conlan Rose Rockstar 3 Years 1000 Posts

    Obviously well doing this I must be careful not to get the alternator wet. I was going to mix the coolant in a new clean 5 gallon bucket because my truck takes 17 1/2 quarts so getting a prefect 50/50 ratio with that number would be a pain. I also bought a flush kit that you attach to the heater hose, only cost 3.00 can't beat that.

    Btw, how do you use the super clean stuff from Prestone? I know there are instructions on the container I just was wondering what they mean. Also need help on the block heater install. I know the install part, but its the removing the frost plug that I don't know how to do.
    Last edited: Dec 7, 2012
  2. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Dude... Don't install that flush kit. Those are NOTORIOUS for leaking, and if your heater line is like mine (and I'm sure it is) they are pre-formed and use a stupid connector to connect to the water pump... replacing the flush kit after it starts to leak is more costly than just buying a piece of heater hose.

    It doesn't matter if you get the alternator wet... It gets wet every time you drive in the rain... Just don't go pouring it directly in the alternator! LOL!

    Be careful when putting in the new thermostat. Don't overtighten the bolts and crack the housing!!!

    Here is a little cheat I developed to mix coolant: You will need an empty one gallon container... an empty coolant bottle is best. Fill up a regular 12 cup coffee pot to the top with water and pour it into the container. There is your 1/2 gallon of water. Fill the rest of the way with anti-freeze. Perfect mix.

    I actually use a 1/2 gallon pitcher that I got from the dollar store but one single 12 cup coffee pot fills the pitcher exactly to the 1/2 gallon mark.
  3. Conlan Rose

    Conlan Rose Rockstar 3 Years 1000 Posts

    Really hmm didn't know that, whatever not like I spent a lot on it. My hoses are clamped at the temp control valve and at the pipes leading to the water pump and engine. No fittings. I haven't installed the flush kit and now I won't.

    I was going to just do gallon of water, gallon of antifreeze in the 5 gallon bucket then pour. Which is pretty much the same as what you are doing just larger container.
    When I do the flush I'll just cover the alternator with a plastic bag so it helps keep it dry. I will be very careful with the water outlet, it looks like it might be aluminum.
  4. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    x2 on what [MENTION=12002]moogvo[/MENTION] said. Don't use that flush kit. I just drain the radiator, refill it with water, pull the upper hose off of the radiator and start the truck. Get it hot so the thermostat opens, dirty coolant will flow out of the upper hose. Keep the radiator full with water the entire time. The thermostat will open and close repeatedly during the process, because you are putting cold water in. When you have clean water coming out then drain the radiator and refill with coolant. But, you will have your thermostat out, so you can just flush it with the truck off and it will take less than half the time. I understand that you want a perfect 50/50 mix. But how do you plan on getting all the water out of the block? Your mix will be off when the coolant you add mixes with the water in the block. As far as the freeze plug goes, the last one I took out was on a 1995. I had to take a screwdriver and hammer and beat it sideways so I could get it out. Sorry to say, With the luck you have had lately doing things on that truck you might want someone else to do it. If you scratch up the surface where the o-ring for the block heater sits then you will have another leak. They get pretty rusty, it might be a real PITA to get out. Then you may have to use some emery cloth or wire brush to clean the bore so the oring seats correctly
  5. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Interesting. My heater hoses are different than yours. Yeah. you can mix it up in a bucket... Just heavier and harder to pour! LOL! Yes, the thermostat cover is very fragile! I think it is pot metal actually.

    Block heaters and snow plow blades... Glad I don't live in New York anymore! (Although I never had a block heater OR a snow plow...)
  6. Conlan Rose

    Conlan Rose Rockstar 3 Years 1000 Posts

    I plan on also using the Prestone flush liquid and won't the truck have to be running because I want to get the coolant out of the heater core...
    I have a pic of the pass side frost plug. The driver side is in better condition just don't have a clear pic of it.

    - - - Updated - - -

    So be super careful unlike how the rest of the truck can be more "manhandled". I want the block heater because I only drive 2 miles to school so by the time I'm in the parking lot the car is finally blowing hot air. Also letting it idle is a waste of gas..
  7. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Put your flush into the radiator and run it for a while before you do the repair.
  8. Conlan Rose

    Conlan Rose Rockstar 3 Years 1000 Posts

    Prestone has two different products the super cleaner and super flush. The cleaner you need to run in the truck for 3-6 hours before draining. While the flush you just need to drain the truck put in the flush(in my case two bottles) and water and run the truck for ten mins.
  9. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Drain it, fill with water, put the bottles in, run it, flush it. You won't need to flush the new radiator so hold off on fixing it until you flush it.
  10. Conlan Rose

    Conlan Rose Rockstar 3 Years 1000 Posts

    Ok, sounds like a plan. I will start with the basic drain and flush using the super flush, then I will do what @Pikey said and flush with the thermostat off. Next, I will remove the hoses I need to remove and others I can easily unclasp to drain the rest of the fluids. After, I will remove the frost plug, temp sensor and old radiator. Fifth, I will install new parts and reconnect hoses. Finally, I'll fill her with a proper mix of 50/50 Dex-cool coolant, run her, and check for leaks.

    I will do a How-To write up so other members will know what to do :smile:

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