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Coolant temperature fluctuates

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Old Jul 25, 2007 | 12:26 AM
  #11  
TheJazz7's Avatar
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Joined: May 2005
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From: Boston
Default RE: Coolant temperature fluctuates

cool, I believe ya...I've been around long enough to know who Hienz is.

So if it's indeed my thermostat sticking open like you suggest...any long term problems associated with that? Engine overheating? How can I properly diagnose and fix? (30V 2.8)
 
Old Jul 25, 2007 | 01:01 AM
  #12  
auditech79's Avatar
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From: Nor Cal
Default RE: Coolant temperature fluctuates

If it gets stuck open, there is a high chance that it can get stuck closed too which is far worse.
The best way to find out if you coolant is really that temp use a temp gun or grab a hold of the hoses and make sure the hoses are at the specified temperature.
If the hoses feel colder than normal then you know that the thermostat is stuck open.
 
Old Jul 25, 2007 | 01:36 AM
  #13  
SAudi's Avatar
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Joined: Nov 2004
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From: Oswego, Illinois
Default RE: Coolant temperature fluctuates

ORIGINAL: auditech79

I hate to be the bearer of bad news but the coolant temp sensor doesn't affect the gauge temp in the cluster in the least.
It just tells the ecm what temp the engine is, there is another sensor for the cluster whichalmost NEVERfails.
If you don't believe me go un-plug your cts sensor and see if it makes a s*** bit of difference on the gauge. It won't.
I would be looking at the thermostat, how many miles are on your car? Have you have the thermostat replaced before.
But auditech79 I did have my sensor disconnected from the harness while i drove tot he store to get a new sensor when mine failed. upon getting home and nearly burning my hand on the coolant line i replaced the sensor and immediatly the temp gauge moved from cold to just below center, something its never dont before, just kinda fluctuating even after changing the thermostat and coolant flush, and the only reason i replaced my sensor was because eventually my gauge just ceased to move. By the way the old thermostat was ok anyways (put it in a boiling pot and sure enough it opened and closed), dont know if things are different on the newer 5v heads but really repalcing the F76 sensor did it for my gauge and feul economy on my 12v.
 
Old Jul 25, 2007 | 10:26 AM
  #14  
TheJazz7's Avatar
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Joined: May 2005
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From: Boston
Default RE: Coolant temperature fluctuates

ORIGINAL: auditech79

If it gets stuck open, there is a high chance that it can get stuck closed too which is far worse.
The best way to find out if you coolant is really that temp use a temp gun or grab a hold of the hoses and make sure the hoses are at the specified temperature.
If the hoses feel colder than normal then you know that the thermostat is stuck open.
Crap. I've got a ton of driving coming up next week (Boston and back) and I don't want my engine overheating. I'm going to the stealership tomorrorow for some work (covered under warrenty) on my leaking exhaust, so i might buck-up and have them diagnose just so I know for sure.

So if the coolant lines are are getting hot before the dash gauge temp reaches 12 o'clock...that means the T-Stat is stuck open? Is there a way to tell if its stuck closed, or do I have to wait until I can't get heat in the winter to find that one out? :-)

My engine is at 52K right now...think it can wait another 10K until I'm due for a timing belt job?
 
Old Jul 25, 2007 | 10:33 AM
  #15  
SouRce4's Avatar
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Joined: Aug 2006
Posts: 246
From: Long Island, New York
Default RE: Coolant temperature fluctuates

i had the same problem not long ago. i took mine out and cleaned it all up with alcohol and stuff. i put it back and it has been working correctly again for like 2 months but last nite i noticed it drop again. Its just the sensor. theres a site on the internet that has them for like $15
 
Old Jul 25, 2007 | 09:40 PM
  #16  
cletusdafetus's Avatar
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Default RE: Coolant temperature fluctuates

thermostat for sure
 
Old Jul 25, 2007 | 10:27 PM
  #17  
auditech79's Avatar
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From: Nor Cal
Default RE: Coolant temperature fluctuates

ORIGINAL: cletusdafetus

thermostat for sure
Right on!A newbie with a brain!
 
Old Jul 25, 2007 | 11:12 PM
  #18  
SAudi's Avatar
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Joined: Nov 2004
Posts: 4,153
From: Oswego, Illinois
Default RE: Coolant temperature fluctuates

i think we should bet, do the $5 diy senosor and see what happens or let him replace the t-stat and all and see what happens. i gots a $50 on the sensor. coincidence maybe but i think it will work.
 
Old Jul 25, 2007 | 11:23 PM
  #19  
cletusdafetus's Avatar
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Joined: May 2007
Posts: 29
Default RE: Coolant temperature fluctuates

mine did the same thing
new sensor did nothing
thermostats spring was weak and would open to soon and never get warm,
new stat problem solved
just replace them both cheap and very easy
 
Old Jul 25, 2007 | 11:26 PM
  #20  
SAudi's Avatar
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Joined: Nov 2004
Posts: 4,153
From: Oswego, Illinois
Default RE: Coolant temperature fluctuates

how much did you pay for the t-stat audi wanted and arm and a leg and a local shop wanted to do the whole t-belt 20k after it had been done.
 



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