Started noticing a gurgling sound after shutting the vehicle no codes

Tiny
WHONOT2BE
  • MEMBER
  • 2002 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 165,000 MILES
I can hear surging in top radiator hose and see fluid rise in expansion tank but there are no code thrown. Temperature gauge usually stays at 210 F most of the time, except recently after driving around seventy five mph on a two hundred and forty mile road trip the temperature creeps about two tick marks up on the temperature gauge. This does not happen until about twenty five miles towards the end of the trip and has happened the last two trips made. I am getting ready to replace the thermostat and lower hose. I have looked at the coolant level and is full and watched to see if any air bubbles in radiator and see no bubbles. Why is the temperature very slowly creeping up? The surge noise is very distinct and you can physically feel in top hose of radiator after turning off the vehicle. The are no visible leaks underneath the car. Any help would be greatly appreciated.
Sunday, November 5th, 2017 AT 6:11 PM

7 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
May be a faulty thermostat or a part blocked radiator, dirty radiator fins restricting air flow, these can all cause your problem.
Was this
answer
helpful?
Yes
No
+1
Monday, November 6th, 2017 AT 4:51 AM
Tiny
WHONOT2BE
  • MEMBER
  • 5 POSTS
Ok, this weekend after installing a new thermostat I no longer hear the coolant surging through the top radiator hose. After driving for about 30 miles the temperature gauge now shows to be at one tick mark just below 210F. Does this sound correct? I am wondering if the new thermostat is working correctly now.
Was this
answer
helpful?
Yes
No
Monday, November 13th, 2017 AT 2:59 PM
Tiny
WHONOT2BE
  • MEMBER
  • 5 POSTS
Also, I notice that the top radiator hose is very hot almost can't touch it bare handed where the bottom radiator is okay to touch bare handed.
Was this
answer
helpful?
Yes
No
+1
Monday, November 13th, 2017 AT 3:02 PM
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Do you know the working temp range of the thermostat you fitted, the temp is stamped on the thermostat.
Was this
answer
helpful?
Yes
No
Monday, November 13th, 2017 AT 3:41 PM
Tiny
WHONOT2BE
  • MEMBER
  • 5 POSTS
Not sure of Temp range of the thermostat. Purchased at advanced auto parts a carquest p/n:14659
Was this
answer
helpful?
Yes
No
Monday, November 13th, 2017 AT 6:16 PM
Tiny
WHONOT2BE
  • MEMBER
  • 5 POSTS
Ok according to the advanced auto website this 14659 thermostat starts to open at 190 F
Was this
answer
helpful?
Yes
No
Monday, November 13th, 2017 AT 6:25 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Top hose very hot with lower hose not too hot could mean any of the following.
1. Thermostat not opening sufficiently.
2. Partially clogged radiator.
3. Weak water pump.

2 and 3 are the most likely cause since thermostat has been replaced and the problem occurs mostly after prolonged high speed driving.
Was this
answer
helpful?
Yes
No
+1
Thursday, November 16th, 2017 AT 12:58 AM

Please login or register to post a reply.

Related Noise Gurgle Content

Bubbling or Gurgling Noises
GUIDE
Bubbling or Gurgling Noises
Your ve­hi­cle can make bub­bling or gur­gling noises for a ver­ity of rea­sons, and can be a sig­nal of var­i­ous un­der­ly­ing is­sues within the ve­hi­cle. Here is why this phe­nom­e­non...
VIEW MORE