Replaced thermostat, now hearing fluid "noise"??? (1 Viewer)

[PapaSmurfj80]

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]

When you changed the thermostat did you replace coolant that was lost during the swap?

Not sure about the other situation.

 

[NLXTACY]

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.

 

[PapaSmurfj80]

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.

 

[john_eckels]

Did you position the jiggle valve ont he T-Stat towards the top?

 

[Trunk Monkey]

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.

 

[PapaSmurfj80]

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.