replaced thermostat in 88 4×4 toyota no heat?

replaced the thermostat in 88 toyota 4×4. Part doesn’t look like the part that came out. Now I have no heat. What could be the problem. I had heat before I replaced the thermostat. The old one made the temp run too hot.
It is currently about 28 degrees outside. Checking temp gauge now.

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3 Responses to replaced thermostat in 88 4×4 toyota no heat?

  1. jeff j June 20, 2011 at 4:52 am #

    either it’s the wrong one or installed upside down.

    however, i’m gonna guess your original issue was this,

    “What happens on the 22R and 22RE engine, when the coolant goes through the heater core it gets cooled off enough that when it gets dumped back in on top of the t-stat it shuts it. Therefore the temperature in the engine continues to go up. The t-stat that I have mentioned has two valves in it, one at the regular temp. and one smaller on at a cooler temp. If the cool water shuts the big one, the smaller one stays open. All this happens because of the lack of a by-pass hose, which on other systems, keeps hot coolant running on the t-stat.”

    "You can get the two-stage thermostat mentioned above from your local Toyota Dealer.
    Part Number: #90916-03070"
    all that was a C/P from, post #6.

    that is your bible. read it!

    a link to a free "factory service manual" can be found here,


    but at 28 degrees with wind chill you may need to put a piece of cardboard in front of the rad. start small and go from there.

    with anti freeze you wont freeze, but that won’t mean the water temp wont be way down there.

    and obviously weak anti freeze may cause this as well.


    owner 93 4×4

  2. Kraka June 20, 2011 at 4:52 am #

    did you make sure to refill the antifreeze?
    Does your vehicle have a temp gauge?

    how cold is it outside?

  3. Wesley June 20, 2011 at 4:52 am #

    You need to make sure the thermostat you put in is rated for the right temperature. Every thermostat is different. The valve on the thermostat will not open until the water going through the system is heated to a certain amount. It may just be that you bought one that opens at a higher temperature then the original. Either check the box it came in or go to somewhere like Auto zone and they will usually be able to tell you if you bought the right one.