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Thread: Heater working soradically; coolant not visible from filler neck

  1. #1
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    Heater working soradically; coolant not visible from filler neck

    Hello all,

    I recently bought my first Toyota Van Wagon (two months ago) and am starting to experience issues with it. The first thing I noticed the other day was that the heater in the front stopped working on occasion. It seemed to work when I was driving on the highway at highway speeds (I never take it in excess of 65 MPH though), but then when I would get to a slower road, the heat would go cold.

    Last night I noticed that the temperature was getting a little high. This worried me, as I hadn't driven the van too much when the temperature started to get up there (never got in the red, it was up there though maybe about 2 centimeters from the red zone on the temperature gauge).

    After last night I decided to investigate my coolant situation. The reservoir is absolutely fine - nice and full and has the correct green color, but when I checked in the filler neck under the radiator cap, I could not easily see any coolant in there.

    I decided to start it up (as it was cold) and look for a moment to see if I could see any coolant movement in there. After a few moments, I saw some white foam stirring around in there (NOT brown or oily looking). I checked the oil and it was not milky nor did it have any white in it.

    I am thinking this is some sort of cooling system issue, but as I am a new owner, I have no idea where to start. The van has 124,000 miles on it and was used only for recreational purposes (i.e. camping) by the previous owner, so it wasn't driven every day.

    I should also mention that when it's really cold, I have to turn start it a couple times, as on the first start (and sometimes second when it's particularly cold out) it will start and burble out.

  2. #2
    Van Fan Kyle's Avatar
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    Re: Heater working spontaneously; coolant not visible from filler neck

    Congrats on the van
    Sounds to me like you've got some blockage in your cooling system. Regarding your heater, that just means it's working a little when there's more hot coolant going around, which shouldn't be surprising. Other than the one coolant shut-off valve controlled by the h/c switch on your dash, and located under the front nose of the van, there's nothing else that controls flow to the heater core. Even if the thermostat (located where the lower radiator hose returns to the block) is closed, coolant will still flow to the heater core. If the van is working harder, and the water pump is moving your coolant around, your marginal (probably partially clogged) heater will just work a little better. That's all.

    The system itself is pretty simple except for the many hard to access hoses.

    This thread is the best reference for an overview

    I'd say to start with a flush of your coolant system as described in this thread, post #5 to try to get some of the scale out of your heater core (and probably radiator, too).

    I wouldn't worry about not seeing your filler neck completely topped off still after some warm/cool cycles unless it seems like your are loosing noticeable amounts of coolant. Top it off here when it's cold, not just at the res tank, to see how much it's missing. Your only worry is that if there's hot exhaust gas bubbling around in your coolant and coming out of the filler neck, it's probably indicative of a blown HG. I don't know if the "foam" you're talking about looks like this.

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    Re: Heater working spontaneously; coolant not visible from filler neck

    Thanks for your advice!

    Quote Originally Posted by Kyle View Post
    Congrats on the van
    Regarding your heater, that just means it's working a little when there's more hot coolant going around, which shouldn't be surprising. Other than the one coolant shut-off valve controlled by the h/c switch on your dash, and located under the front nose of the van, there's nothing else that controls flow to the heater core. Even if the thermostat (located where the lower radiator hose returns to the block) is closed, coolant will still flow to the heater core.
    So I filled up the filler neck with coolant so I can go buy the flush kit (going to do a flush later today) and the heat almost instantly worked. I'll keep you posted on what happens after the flush.

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    Re: Heater working spontaneously; coolant not visible from filler neck

    I'm wondering if a coolant system pressure test would be worthwhile at this point before I do the flush.

    This might reveal that the thermostat's bad (which is what I'm suspecting is the issue), and could save me some time.

    What do you think?

  5. #5
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    Re: Heater working spontaneously; coolant not visible from filler neck

    Quote Originally Posted by tennesseetoyota View Post
    So I filled up the filler neck with coolant so I can go buy the flush kit (going to do a flush later today) and the heat almost instantly worked..
    How much coolant did you have to put in? If it was very much, this tells you that your van's heat gets weeny because the coolant level gets too low to allow the coolant to circulate to the heater core. If so, that's why your engine also is getting hot not enough coolant. This is a pretty dangerous situation for the future of your engine you'll want to find why the coolant disappears ASAP.

    Coolant gets low because of a leak somewhere. Pressure testing can help you find that ... if it's not the headgasket.

    Failure to draw coolant from the overflow tank is most commonly due to a bad radiator cap, but that can also occur when the hose from the overflow tank to the filler neck has a breach (which allows air in, interrupting the continuous siphon from overflow to the coolant jacket proper). Caps are cheap, so changing that is a good idea. Although the preformed filler-neck-to-overflow-tank hose was still available from Toyota recently, it's also easily replaced with bulk hose.

    Gwen
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    1989 4WD 5-speed DLX; 410K and an odd sense of humor ("Skylervan")

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    Re: Heater working spontaneously; coolant not visible from filler neck

    Hey Gwen, thanks so much for the information. It took maybe something like 1/3 to 1/2 a gallon of coolant to get it up to where it was visible in the filler neck. Fortunately I didn't drive it much at all after I noticed that the engine temp was up there a bit.

    I'm going to get a pressure check done early tomorrow morning. I'll let you know what I find out.

    I'm also going to get them to test for exhaust gases in my coolant, which hopefully will come back negative. I dread the thought of finding out that the van has a blown head gasket, so let's hope for the best...

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    Post Re: Heater working spontaneously; coolant not visible from filler neck

    Okay, so I got a pressure test on the cooling system done and also got a test for exhaust fumes in the cooling system done.

    The test for exhaust in the cooling system came back negative, so it's not a blown head gasket (thankfully).

    The cooling system pressure test resulted in the discovery that the water pump was seeping pretty badly, which is the purported cause of my loss of coolant. Furthermore, the mechanic who performed the test said that the radiator looked the bottom was bout to fall out. They recommended replacing the radiator, the upper and lower hoses, and the

    Additionally, they discovered that an air boot (the "air induction hose") which goes onto the throttle body was dry-rotted to heck but obscured by electrical tape, thus causing a vacuum leak which was why the van was starting hard when cold.

    The funny part is the rate they quoted the repairs at. They were offering a water pump for $80, a radiator for $500, the thermostat and gasket for $42, the upper radiator hose for $50, the lower radiator hose for $62, and the air boot for $126. This plus their labor rate made their quote for the repairs at around $1900 (almost as much as I paid for the van).

    So this leads me to the question, can I get the parts for the van from anywhere else at a cheaper rate. These rates seem artificially high to me (the thermostat especially, as I normally think of thermostat prices in the range of $12 or so).

    Furthermore, do you think I could just get the radiator re-cored instead of replaced since it's a metal radiator or should I not bother?

    Thanks so much in advance, you all are legends.

  8. #8
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    Re: Heater working spontaneously; coolant not visible from filler neck

    Hey tenesseetoyota,

    My van suffered from similar issues as yours. My coolant reservoir seemed to not lose any coolant at all while the filler neck would go lower and lower. Sure enough, it was a leak from the water pump much like you found. A tell-tale sign is if the fan has any play in the lateral direction - that means your bearing is shot and that's where coolant is leaking through. So I went ahead and ordered that parts. While you're in there, it's a good idea to replace the following parts:

    Water Pump - Aisin - http://www.rockauto.com/en/moreinfo....279841&jsn=372 $35
    Fan Clutch - Aisin - http://www.rockauto.com/en/moreinfo....279841&jsn=379 - $57
    Thermostat - Toyota - Toyota P/N 90916-03046 - ~$15
    Upper Hose - Gates -
    http://www.rockauto.com/en/moreinfo.php?pk=3485&cc=1279841 - $6.67
    Lower Hose - Gates - http://www.rockauto.com/en/moreinfo....482&cc=1279841 - $6.48
    Radiator Repair - Ability Radiator - Yuba City, CA (530) 673-0813 - $85

    While I had the front seat and the doghouse off, I figured I'd do as much preventative maintenance on the cooling system as I could and the parts above are what I deemed necessary. Folks around here highly recommend nothing but the toyota thermostat and I tend to be an OEM stickler as well - Aisin when I can or straight up Toyota when possible. Gates for the hoses as there's nothing better. As for the radiator fix - Ability Radiator is the go-to around here. I live in YC so it's easy enough for me to head down to Ability - I got my radiator the next day all ready to go. A popular mod here is to get their hi-efficiency 4 row radiator modification. It's pricey, but if you'll be doing off roading or operating in extreme driving conditions, it may be worth considering. Just know it can be upwards of $400. My simple repair was $85.

    So, adding everything up brings the total to - ~$206, in just parts. If you do all the labor yourself, you could save a pretty coin ~$1700 to be exact. After doing all these modifications, I drove my '89 cargo to LA from SF over the grapevine and back without a hitch. I can't recommend doing these upgrades enough as it's given me a ton more confidence in my van. The only thing I regret is not documenting this process for the next person. It's really something that should be done on any new van with unclear maintenance records just for piece of mind.

    I'd be happy to help you out on any of this if need be. Good luck, let me know how it goes!

  9. #9
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    Re: Heater working spontaneously; coolant not visible from filler neck

    Do you know if these parts can be for 4wd as well? My van is an 89 and is having similar problems but is 4wd.

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