Replaced thermostat, now hearing fluid "noise"???

Joined
Jan 26, 2009
Messages
106
Location
Alabama
I replaced my thermostat yesterday, along with the cold-start switch and I have 2 questions....

When I turn off the LC, I am now hearing all kinds of fluid drainage and noise. Did the new thermostat allow some the flap open to allow fluid to escape to the heating system, which I presume would be normal or is there something else I am missing? There are no leaks just a lot of noise for a few seconds after turning off the LC. All of the hoses are new, OEM radiator is a month old, cap is new, fluid is new.

Also, when I first bought the LC, I noticed that a switch was broken off near the thermostat housing and I had no clue what it was. Turns out it was the cold-start switch right above the cooling temp sensor. Since I was in there, I went ahead and replaced it. but it costs me $150 OEM. Now, somebody please make me feel better for paying so much for the tiny little piece of a metal tube. What is it for? I live in the deep south so temps do not drop too low and my rig ran fine without it. Just curious.

92 fj80 133K miles
 

94SRUNNER

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Joined
Oct 9, 2006
Messages
3,240
Location
Dayton, OH
When you changed the thermostat did you replace coolant that was lost during the swap?

Not sure about the other situation.
 

NLXTACY

Wits' End
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Dec 7, 2007
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West Hills, CA
Did you properly air bleed the coolant system? More than likely you are hearing air. If it is then you increase the chances of over-heating.
 
Joined
Jan 26, 2009
Messages
106
Location
Alabama
I turned on the engine and slowly let ir un while topping it off with fluid. Is there an air bleeding valve that I am not seeing or a screw valve? The temp guage seems to show normal temps.

At this point, since I have put about 25 miles on it, can I just take off the radiator cap and let out any trapped air? Sorry, I am a first timer with radiator work.
 

Trunk Monkey

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Joined
Apr 27, 2003
Messages
9,140
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Salt Lake City
It seems like the straight 6 is notorious for air pockets. I've replaced radiators on my 60 and 80 and dealt with air in the system. On the 60 I had to jack the front end clear up to get bubbles out and on the 80 I used a friend's very slick Snap-on radiator fill kit. It pulls vacuum on the hole system and them sucks coolant in to replace, guarantee no air.
 
Joined
Jan 26, 2009
Messages
106
Location
Alabama
Think I have it fixed! Should have read more on the forum before posting (did read the FAQ though). I did a burp on the incline and that seemed to work. Thanks very much to all for the suggestions and check-offs.
 
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