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Old 09-04-2011, 08:07 PM   #1
FMJ_Blazer
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Temperature spiking

Hope someone can help me. Have a 71 blazer with 355 blueprint engine with electric fan and stewart warner gauges and matching sending unit. Temperature was solid at 195, but the other day on my way home from work, the gauge spiked at 240. I slowed down and it dropped to 200 or so. It will spike up and then settle down again. Engine has 300 miles on it. It will do this under a varying of situations - subdivision to highway, makes no difference.

I searched and could not find similar problem.
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Old 09-05-2011, 01:53 PM   #2
rsavage
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Re: Temperature spiking

There are a lot of variables. Is the radiator clean and of ample size to cool the new engine - i.e. Do you have a 4 core or 2 core (if stock copper/brass radiator)?. Are you sure that you have no air pockets in the coolant or did you push some out over the first few days of running so that now it is low? Do you have a stat in it? You could try a 165 or 180. If it got that hot, I'd replace the stat. My experience is that once they've been overheated they don't work properly. Don't have a lot of experience with electric fans so couldn't venture an opinion other than what temp do you have it set for turning on? Is it moving air the right way? Shroud on it? Timing not too far advanced? Radiator hoses not collapsing when running? These are some of the things I'd look at in trying to diagnose the problem. Good Luck - keep us posted.
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Old 09-10-2011, 11:43 AM   #3
FMJ_Blazer
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Re: Temperature spiking

sorry for the delay in replying...had to travel this past week. I appreciate the response and questions to spur some thinking Yukon. Electric fan is on inside and pulling air through so no shroud. Hoses are not collapsing. I just bought a new 180 thermostat and will install today. 180 is where the fan is set to come on. I guess I could lower that. The advance is a little high at 14 based on recommendation from blueprint engines. The radiator is a brand new unit and it has been a year since i bought it. Believe it is a stock 3 row from LMC. You mentioned air pockets. How do i know if I have or how to get rid of?

What is weird is that my left bank is running hotter than my right. Not sure why.

Last edited by FMJ_Blazer; 09-10-2011 at 11:49 AM.
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Old 09-11-2011, 05:03 PM   #4
BobbyK
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Re: Temperature spiking

Did you let the system "burp" itself after filling the rad the 1st time?
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