Civic VX not circulating coolant - Fuelly Forums
Go Back   Fuelly Forums > Tech, Troubleshooting and Repair > General Maintenance and Repair
Search Today's Posts Mark Forums Read
Thread Tools Display Modes
Old 11-24-2008, 09:55 PM   #1
Registered Member
XxDrUnKnMuNkxX's Avatar
Join Date: Oct 2008
Posts: 20
Country: United States
Civic VX not circulating coolant

So Ive been troubleshooting a high and bouncing idle and have read about air in your radiator/hoses being one of many possible culprits. Before bleeding the radiator of air bubbles I wanted to make sure it was actually circulating coolant. I took it for my morning commute, which is about 30min 20miles mostly freeway and at my destination, popped the hood and felt the radiator hoses. The top hose was warm but the bottom hose was still cold. The car is not overheating, just having idle problems and is getting less than stellar gas mileage. Now Im looking to troubleshoot this problem, other than buying a new thermostat, what else would cause something like this. Any input is greatly appreciated.

XxDrUnKnMuNkxX is offline   Reply With Quote
Old 11-25-2008, 03:07 AM   #2
Registered Member
djenyc's Avatar
Join Date: Feb 2008
Posts: 119
Country: United States
I had similar symptoms with engine racing at idle reported here:'ve
and here:

Ultimately it was a bad MAP sensor in my case.

It could also be dirty or malfunctioning IACV, or vacuum leak, etc, but not air bubbles in coolant.

djenyc is offline   Reply With Quote
Old 11-25-2008, 04:53 AM   #3
Registered Member
Join Date: Apr 2008
Posts: 1,090
Country: United States
Your top hose should be hot and the bottom hose warm. You might start it cold with the radiator cap off. If the coolant is circulating before the engine warms up your thermostat is either missing or not working properly.

My hands are pretty tough, with my engine running I can hold my hand on the top hose for about 5 seconds before it begins to hurt. Thats 180 degrees. The bottom hose will be much cooler depending on how well your radiator is working, usually about 120 degrees.

Is the temp guage reading normal? If it is not getting up to its normal operating range, it,s a good indication of a bad thermostat.

Nissan thermostats fail in the open position, so the engine runs too cold and mileage will suffer greatly.

If your coolant was not circulating, your engine would overheat in a short distance, certainly before 30 minutes.

R.I.D.E. is offline   Reply With Quote
Old 11-25-2008, 06:18 AM   #4
Registered Member
XxDrUnKnMuNkxX's Avatar
Join Date: Oct 2008
Posts: 20
Country: United States
The top hose is only warm, I can hold onto it with no problem. The bottom hose is cold. The temp gauge is reading about 1/3 the way up, def not overheating. Now that I think of it, I dont think Ive ever heard the fan turn on, even while idling in my driveway, working on the car.

Edit: I lied, that ish was hot, but the bottom hose again is still cold.
XxDrUnKnMuNkxX is offline   Reply With Quote
Old 11-25-2008, 08:25 AM   #5
Join Date: Oct 2008
Posts: 72
Country: United States
Location: Littleton, CO
If you're not overheating, I don't think you have a problem. You said it was mostly highway driving, which is pretty effective at keeping a radiator cool, especially this time of year. If the top hose is hot, theres nothing wrong with your thermostat or water pump. I agree with djenyc, its not a coolant issue.
nowhhs is offline   Reply With Quote
Old 11-25-2008, 03:58 PM   #6
Registered Member
Danronian's Avatar
Join Date: Aug 2007
Posts: 652
Country: United States
I agree that it sounds like your coolant system is working fine.

Check to make sure your throttle body cable is properly adjusted, that your IACV is clean, your throttle body is clean, check for vacuum leaks (sometime they form at the PCV elbow), and that your ignition timing is properly adjusted.

Those are all possible reason why you could have the issue with your idle. Good luck.

On the never-ending quest for better gas mileage...
Danronian is offline   Reply With Quote
Old 11-25-2008, 10:08 PM   #7
Registered Member
XxDrUnKnMuNkxX's Avatar
Join Date: Oct 2008
Posts: 20
Country: United States
While cleaning out the IACV I lost a bit of coolant. Any suggestions on how to remove the air in the lines if the coolant doesn't even circulate.
XxDrUnKnMuNkxX is offline   Reply With Quote
Old 11-26-2008, 02:45 PM   #8
Registered Member
kamesama980's Avatar
Join Date: Nov 2007
Posts: 742
Country: United States
Location: Columbus, IN, USA
Send a message via AIM to kamesama980 Send a message via Yahoo to kamesama980
the IAC hose should be small enough to pass the bubble without any work on your part.

again, coolant IS circulating or you would have overheated long ago. a closed thermostat won't let the upper hose get warm AT ALL. coolant not circulating will blow the engine in just a few minutes. if the weather near you is like it is here (about 20f this morning) the upper hose won't get that hot and the lower hose certainly won't be warm. as already stated, either your thermostat is stuck open, missing, or your engine just isn't putting out that much heat.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
kamesama980 is offline   Reply With Quote
Old 11-29-2008, 02:32 PM   #9
Registered Member
brucepick's Avatar
Join Date: Feb 2007
Posts: 722
Country: United States
Location: Connecticut
I recently had my t'stat replaced with one from the Honda dealer because the old one didn't keep the system warm enough. It rose much more slowly than I expected from driving other cars and even after warmed up as much as possible (say, a half hour on the highway) the upper hose was only warm to the touch and not hot.

The big tipoff in my case was black soot on the bumper near the exhaust. I figured the computer was forcing it to run rich due to being cold. I wiped it off and it didn't come back after getting the t'stat replaced.

With new t'stat in, the upper hose is hot to the touch. I can keep my hand there but it's pretty darn hot. Temp gauge (mine is a '97 HX) goes to dead horizontal on the gauge every time.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.

Now driving '97 Civic HX; tires ~ 50 psi. '89 Volvo 240 = semi-retired.
brucepick is offline   Reply With Quote
Old 11-29-2008, 04:27 PM   #10
Registered Member
Jetta90GL's Avatar
Join Date: Mar 2008
Posts: 75
Country: United States
Another thing that could be causing poor circulation is a bad water pump. If the coolant hasn't been changed in a long time it can become acidic. I've seen the steel impellers corroded completely off of water pumps before.


Jetta90GL is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Is there a OBDI or OBDII conversion for older vehicles? kozaz General Fuel Topics 3 11-13-2007 07:32 PM
ICE loads basjoos Experiments, Modifications and DIY 9 11-11-2007 08:32 PM
DSG and CVT Erdrick General Fuel Topics 2 10-13-2007 05:41 AM
Blast from the past: Mobilegas Economy Runs? Spule 4 General Fuel Topics 8 11-20-2006 07:47 PM
Let the games begin! Matt Timion General Fuel Topics 3 08-18-2006 07:22 AM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -8. The time now is 12:42 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.