Serious temp guage fluctuation

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sumo

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had similar problem with my 89. Had blockage/trapped air in the heater core. I replaced the tstat and had the same probs. I ended up taking the hoses off the core and shot a garden hose througn one of the hoses. Cleared out the blockage. Seems to be fine now. You can get one of those prestone flush kits from any auto store
 

07Burb

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Ahhh...I thought I remembered 180 being stock. My bad on that. Go with the 195 if it's what came stock :waytogo:
 
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raptorforme93

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I am taking a trip to Oreilly's tomorrow after my 8am class. The problem is that I live in a dorm in Tallahassee now, and I dont have ANY of my tools at all. So i'll have to see what tools I can borrow. Haha. And ok I'll grab the 195 tstat. Maybe 07Burb is just out to get me?!?! :secret:
 

bottomline2000

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banking on low coolant. clogged heater core would explain the heat problem, but not the gauge. bad thermostat would explain the temp gauge, but not the heat problem. common denomenator, no/low coolant flow.. I win?

You can test the thermostat by feeling the hose next to it once the truck is warmed up. If it stays cool the stat isn't opening. If your radiator has a cap you may need to burp the system as an air pocket can cause the issue your having.
 
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raptorforme93

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I will take a look at the coolant level in the morning and Ill also feel the lines in the morning. Would it be possible for me to change the tstat in the parking lot with a few tools or is it more in depth than that? And how would I go about purging extra air from the radiator?
 

retorq

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banking on low coolant. clogged heater core would explain the heat problem, but not the gauge. bad thermostat would explain the temp gauge, but not the heat problem. common denomenator, no/low coolant flow.. I win?

You can test the thermostat by feeling the hose next to it once the truck is warmed up. If it stays cool the stat isn't opening. If your radiator has a cap you may need to burp the system as an air pocket can cause the issue your having.

No sorry you no win nothing, I mentioned low fluid in post #4. :)
 

SunlitComet

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when refilling I leave thermo and housing fill radiator very slowly till you reach the point that bottom half of thermo is sitting in coolant when is place. literally coolant would be about 1/2 below the manifold machined surface. mount everything down as as you top of radiator bend the highest point on hose toward flat and let it fill itself. Spend a few minutes and do that and top of until it will not take anymore. Fill your reservoir to the hot mark. As you make several cold hot cycle with engine over a few days. Remaining air should bleed it self into reservoir and it should level off in a few days. Just keep an eye on it.
 
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raptorforme93

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You guys are the best! I replaced the tstat and added a GALLON AND A HALF of anti freeze and BOOM, instant super hot air and a steady temp reading :D Thanks a ton guys!! I will be monitoring my antifreeze level over the next week or two
 

Ceejkay

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i was getting the same issue a while back and immediately went to the tstat. come to find out the water pump was going out and there was air getting in the system.. but i was also leaking a small amount of coolant
 
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raptorforme93

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I don't think that my tstat was even messed up but I went ahead and changed it. Everything looked pretty clean when I took it apart really. I'm not sure how I was so low on coolant so I'll be monitoring it for a while.
 

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