Temperature Issue

One wire sensor. Just replaced it 2 weeks ago.

When reading it through the OBDII port it seemed logical the couple times we checked it. I might check it one more time today just to make sure.

One thing I did notice yesterday after we re-grounded everything and started it up was that when the gauge was climbing up to 260, the air the fan was pulling through the radiator was not all that warm feeling, then all of a sudden when the t-stat opened (after being on 260 for several seconds to a minute) it got HOOOOOOT! We used a laser thermometer to check the temp at the sending unit and it read 205 after the gauge had settled just below 210.

That sounds like it's got an air pocket in the engine. I'm not sure how you bleed air out of the older vortecs but you have to open the highest point on the engine and fill until water comes out of it.

I've filled it each time when I changed the t-stat, and have opened the radiator cap and let it run for God knows how long and kept it full. I can't find instructions anywhere.

<div class='quotetop'>QUOTE(JayBo &#064; Apr 25 2007, 10&#58;47 AM) [snapback]91351[/snapback]</div>

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I&#39;ve filled it each time when I changed the t-stat, and have opened the radiator cap and let it run for God knows how long and kept it full. I can&#39;t find instructions anywhere.
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Yeah, either air pockets or not the correct mixture of coolant/water. Bleed the system WELL. Most of the air in the system should burp out through the overflow tube...

Also make sure that the coolant/water mixture is either 60% coolant/40% water or 70% coolant/30% water. I use 60/40, but you may need a 70/30. It sounds like it is heating up fast, then the t-stat opens...it cools....t-stat closes....heats up....etc. You might want to try and install a lower temp t-stat. Your heater won&#39;t be as hot (and it will take a LOT longer for the motor to warm up), but we all know that heat is the main enemy of engine performance and longevity. A 180 t-stat may be what you are seeking...

I dropped it off at the shop yesterday while I went to pick up a new Hemi Charger I gotta equip, and this morning my mechanic calls me and says he started it up and sat there with an infared thermometer and shot it at the temp sensor while it warmed up.

He sais the head is ACTUALLY getting to 260 so its not a mis-reading. He said it stayed up at about 260-275 for a minute or so then the t-stat opened and it went to 205 or so then back up to hot and back to normal.

Could the guy that fixed it in the first place have installed the intake or head gaskets improperly and blocked off a coolant port?

<div class='quotetop'>QUOTE(JayBo &#064; Apr 26 2007, 07&#58;55 AM) [snapback]91443[/snapback]</div>

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I dropped it off at the shop yesterday while I went to pick up a new Hemi Charger I gotta equip, and this morning my mechanic calls me and says he started it up and sat there with an infared thermometer and shot it at the temp sensor while it warmed up.

He sais the head is ACTUALLY getting to 260 so its not a mis-reading. He said it stayed up at about 260-275 for a minute or so then the t-stat opened and it went to 205 or so then back up to hot and back to normal.

Could the guy that fixed it in the first place have installed the intake or head gaskets improperly and blocked off a coolant port?
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Yes, that is a very possible scenario. Blocking off one port should not let the block or head temp rise to that point though... I am not sure, but 260-275 is pretty damn hot for the 5.7L Vortec to be running. I would say that 240 is the max temp. where it should run... Try installing a 180* t-stat. I know that installing a lower temp t-stat will not solve the problem with it fluctuating so frequently, but it will help keep the temps in a more normal range. You may want to do a REALLY GOOD coolant flush, then mix in the coolant a little thicker than the water (65-35 mix) and do the 180* t-stat...

Its up to the mechanic now. I gave up on it and put it in the shop. He said they&#39;d more than likely want to take the intake back off and replace BOTh head gaskets this time instead of just one like the other jack leg did.

I&#39;m going to take pics and document the whole thing if thats what they do so the warranty company won&#39;t try to sue me&#33;

if they decide not to, I&#39;ll do the steps you listed above. Thanks&#33;

After doing some testing yesterday, we found out that ONLY the head that jackass worked on is getting up to 240+ degrees. The one he left alone didn&#39;t get above 195. So its gotta be something either in the intake gasket or the head gasket. It&#39;ll be torn apart next week and fixed.

<div class='quotetop'>QUOTE(JayBo &#064; Apr 27 2007, 08&#58;35 AM) [snapback]91546[/snapback]</div>

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After doing some testing yesterday, we found out that ONLY the head that jackass worked on is getting up to 240+ degrees. The one he left alone didn&#39;t get above 195. So its gotta be something either in the intake gasket or the head gasket. It&#39;ll be torn apart next week and fixed.
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Good to hear that your mechanic finally figured out what went wrong. Hope all goes well after it is fixed.

Thanks man. I&#39;ll post what was wrong so everyone can laugh&#33;