Frozen thermostat or heater core?

cravendouglascravendouglas Band Wagon
in Engine & Drivetrain
I'm at a loss and am wondering if anyone can help me. First off, I have a 2wd wagon with a d15b2 in it. Now the problem. I was driving to work last night and my car ran fine but I was getting cold air instead of heat. I figured it was just the heater core and I would fix it the following day. But on my way home my car was starting to sputter and trying to die. It also started to over heat, so I pulled over to the side of the road and popped the hood. I noticed I had a coolant leak somewhere in the front of my motor. I can't tell if it's coming from one of my hoses or somewhere else, I can't find the leak. After looking for about 20 min I gave up and tried to drive it home. On my way home my car would start to over heat when I would go over 20 mph. So I stayed at 20 and made it home. Is it possible that my thermostat or heater core freezing causing a hose to bust? Or my block to crack for that matter?

Comments

  • bkmc24bkmc24 Senior Wagonist
    Thermostats are ultra cheap. I would go snag one, drain all of the coolant, flush the system and ensure the heater core isn't clogged.
  • cravendouglascravendouglas Band Wagon
    Do I have to pull the heater core out to see if its clogged? And would a clogged core cause leakage? Is there a weep valve somewhere in there?
  • bkmc24bkmc24 Senior Wagonist
    Take both hoses off the core and use a garden hose to flush it. Hold it to one side, turn it on, and see if water comes out the other spout, and if debris comes with. Clogged core wouldn't mean leaks either, so no. My suggestion is check the quality of the rad hoses and heater core hoses. Any of them look bad, or even possibly bad, spend the money and get all new ones and a new thermostat. Flush the entire system, and put all new coolant in and go from there.

    Cheaper way would be to actually find the leak in daylight. Theoretically, a stuck closed thermostat could build pressure, causing a leak somewhere as well as no heat.
  • cravendouglascravendouglas Band Wagon
    Ok cool. thank you bk. Hopefully that's all it is. I will check it tomorrow and come back with the results
  • bam-bambam-bam Council Member
    No offense to Ben, but flushing core and changing hoses wholesale doesn't go to the root of your problem.

    Overheating and no heater together spells no coolant or no coolant flow. It is the classic symptom of freeze damage, which you mentioned already.

    Do you have reason to believe it might have gelled? Did you have enough antifreeze in the mix?

    do this:
    1) check the oil. If it is overfull and milky there's internal freeze damage. But...
    2) since you've already told us there's an external leak, pour it full of coolant and identify the source. The bad news is that hoses dont freeze and burst,they can expand. Metal parts do break. It's very important to know where the leak is to make a good repair decision.

    In other words, don't throw a hundy worth of hoses, stat and coolant at it until you know the block is ok. Look for a waterfall behind the exhaust manifold.
  • bkmc24bkmc24 Senior Wagonist
    bam-bam wrote: »
    No offense to Ben, but flushing core and changing hoses wholesale doesn't go to the root of your problem.

    Overheating and no heater together spells no coolant or no coolant flow. It is the classic symptom of freeze damage, which you mentioned already.

    Do you have reason to believe it might have gelled? Did you have enough antifreeze in the mix?

    do this:
    1) check the oil. If it is overfull and milky there's internal freeze damage. But...
    2) since you've already told us there's an external leak, pour it full of coolant and identify the source. The bad news is that hoses dont freeze and burst,they can expand. Metal parts do break. It's very important to know where the leak is to make a good repair decision.

    In other words, don't throw a hundy worth of hoses, stat and coolant at it until you know the block is ok. Look for a waterfall behind the exhaust manifold.


    I agree. My "fix" is entirely shot gunning parts and not trying to find the fix. Also why my second mentioned was the correct route. I guess I always assume people know to try and find the issue before buying stuff, but then again I need to stop that as well lol. I was mainly answering his questions as opposed to reading into the issue more.
  • cravendouglascravendouglas Band Wagon
    I've checked my coolant level and I do have a good amount of coolant. The only thing I can*think of is when I flushed the system a couple of months ago, I possibly didn't get all of the water out of the system and maybe it caused some freezing in there somewhere. But I put 50/50 in after I flushed the system. Is it possible that the cheap antifreeze I put in couldn't handle the low temperature and froze? I checked my oil and it looks like its ok. And the leak isn't a gusher its more like a steady stream that looks like its coming from behind the mani or near the water neck. There's coolant all over the front of my motor. If my block is cracked, wouldn't there be coolant coming out regardless of my car running or not?
  • cravendouglascravendouglas Band Wagon
    I got the chance to get out and look at my car. I didn't see any coolant lines leaking and the block didn't look cracked. I started my car and let it warm up, then took it for a drive. It drove perfectly and didn't leak any water. Now am I being to optimistic if I think that the stat froze, causing coolant to leak out of my rad cap onto my fan, and my fan flinging it everywhere?
  • jpciiijpciii familEE
    If you flushed the system with H2O and didn't drain enough of it out, then your 50/50 mix would be diluted once mixed inside the system. How cold was the weather when it gave you the trouble? Single digits? Sounds to me like the coolant was indeed frozen inside the radiator and heater core. Meanwhile, the very hot engine coolant was at a very high pressure and forced a temporary leak past a hose clamp or thermostat gasket or your radiator cap or whatever. If you think my hypothesis is true, you can drain out some of your diluted coolant and add some straight antifreeze back into the system. Instead of discarding what you drain out, I would save it for later... and add a bit of straight antifreeze to THAT also.
  • cravendouglascravendouglas Band Wagon
    It got down to 4 degrees and I work by a river so I imagine there was a nasty wind chill as well. But I do think your hypothesis was correct. I think that the too diluted coolant froze my stat not allowing coolant to pass to the core. On a warmer day, I drained all of the fluid and installed a new thermostat. I then put the coolant I drained out back in burped the system and I haven't had a problem since. (Fingers crossed)
  • jpciiijpciii familEE
    Changing the thermostat doesn't solve the problem. If the temps ever get that cold again, your coolant will freeze again. The coolant in your running engine will heat up and flow just fine in a matter of minutes... including around the thermostat because it's right there on the hot engine block. The frozen coolant in the radiator and heater core, however, will remain frozen and your engine will overheat because it can't evacuate the hot coolant from the engine and bring in cold coolant from the radiator or heater core. You need a higher concentration of antifreeze mixed into your cooling system so that it stays fluid at lower temperatures and doesn't freeze up.
  • cravendouglascravendouglas Band Wagon
    Thank you for reminding me jpc. I forgot to add more concentrated antifreeze to my cooling system. When I get off work I will do it
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