Radiator - burp again

Discussion in '60-Series Wagons' started by mpeagan, Nov 3, 2005.

  1. mpeagan

    mpeagan

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    After replacing all hoses and adding new antifreeze I "burped" my 1988 FJ62's system numerous times. All on a slight incline, heater and rear heater turned on. I let it run for 15 minutes turn it off let it cool, run it again for 15 minutes. I did this several nights in a row. Waited a week, repeated it. I still have a problem, intermittently, while driving the temperature gauge will climb to HOT, then immediately start falling. All other time it hangs around the 1/4 to 1/2 lines. Other than taking it in, any suggestions? Thanks in advance. BTW, this is in NC. It has been a hot summer, but cool weather has come and it is still doing this.
     
  2. karlec

    karlec

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    I have the same problem and I've been working on it for quite a while. It's as if the thermostat doesn't open very much and the temperature at the back of the engine (where the temperature sender is) climbs until finally the thermostat opens and then it all cools down. It does this more on cooler days than on hot days. I think maybe on hot days the thermostat is open further and water is circulating better. I've noticed that with either heater water valve turned on it doesn't do it. Don't need the heater fan on, just the valve. Now I always run with the rear heater valve on.

    I have two '84 FJ60s. One has this problem and the other doesn't. Another funny thing is that just after filling the cooling system (and burping it) and for the next few days it doesn't do it at all. Then it gradually increases over the next couple weeks.

    Here's what I've done to try to fix it: New thermostat, new radiator core, new bypass hose. Pulled the head and all the freeze plugs to clean all the water passages in it and in the block. All new heater hoses. Flushed out both heater cores and rear heater piping.

    It seems like the water at the back of the head near the temperature sensor isn't circulating very well but turning either heater valve on gives it a way to circulate. Measuring the temperature at the thermostat housing with an IR thermometer is always about 185 so I know the thermostat's working ok.
     
  3. CTiger

    CTiger

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    Are y'all's gauges just spiking (going up fast and then right back down)? If so, this may just be the gauge. The next time it happens, look to see if the fuel gauge is rising as well. The fuel and temp gauges share a ground, and sometimes they lose that ground for a sec and both spike. This happens to my rig every once in a while. If this is your case, you can clean the contacts on the back of the gauge or you can just buy a new gauge.

    When it happened to me: thread here
    I may be completely off, but hope this helps
     
  4. mpeagan

    mpeagan

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    For my rig (88 FJ62) it happens mostly on warm to hot days. Yes, the Temp gauge spikes. No, no other gauges move. It usually happens at a traffic light, and I am watching the gauges. Once I get moving, it bounces back. When it happens on the road, it gradually starts to climb, then spikes quickly at HOT and bounces right back to 1/2 position.
     
  5. krzyabncanuck

    krzyabncanuck USFS HOTSHOT

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    Mike it sounds to me if it does it mostly at a light then it could be that the fan clutch needs to be rebuilt or replaced.

    HTH
     
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