I am second owner if 2005 Civic 1.7L AT sedan with 200,000 miles. It has had an overheating problem with me as well as previous owner. When driving on highway it shows no problem. It's when I exit the highway and come to a light that it heats up. I replaced radiator, hoses, thermostat, temperature sensor.
​​​No issue when driving in town. Head gasket test was negative. Timing belt and maybe water pump were apparently replaced in 2017. Water pump is the only part I haven't checked or replaced.
Any recommendation on what I should check next?

 

Air pocket ? How's the heat ? if it's intermittent there could be an air pocket , remove the small hose by the head and use a shop vac to suck out coolant with another hose on the nipple and in a jug of coolant . Sometimes these motors will drive you buggy with the over heating thing .

 

Some good reads below: (head gasket failure is a common denominator)

https://www.civicforums.com/forums/1...low-speed.html
https://www.civicforums.com/forums/3...ng-issues.html

 

Thanks for the reply benchwarmer
1. I ran the engine for 45 minutes (to burp the cooling system) and was still seeing some air bubbles.
I lifted the front part of the car because the radiator in this car lays low (according to a Honda technician)
2. The heat seems to be ok
3. I am not sure which small hose and nipple you are referring to. Can you provide a description or picture?
4. This overheating thing is driving me nuts. My son drives it to school and back (inside the city) without any problem

Thanks

 

On another note ... I just checked the coolant level and it went down a smidge. I also noticed a 3 inch hairline crack just above the front oxygen sensor (see attached picture with arrow pointing to the vertical hairline crack). Is it possible the engine may be sucking air through this hairline crack? Thanks

 

If the heat is steady then it's probably not an air pocket problem , the hose I'm talking about is a heater hose that comes from around the throttle and into the block just behind the thermostat area . If you get a clear hose on that bridging the gap and the coolant flows through then the water pump is good , if it doesn't it's still not a clear indication of a bad water pump , I found that out the hard way . I have an 04 civic that had similar problems , it's in the back yard now and after doing all the other stuff I have to say it was an air pocket . I'll also never buy another $5** thermostat , I went top the honda dealer and paid $40** , a crappy one can cause problems and uncertainty

 

The crack in the exhaust manifold is not uncommon and will make noise when it becomes a problem (exhaust leak ) It can be brazed I've been told but it takes a little skill and must be cleaned well .

 

Thanks for clarifying that the pictured vertical crack is in the exhaust manifold and not the engine block. Do u think JB Weld can effectively seal the crack?
It is a hairline crack and does not seem to be a problem at this point.

 

Hi benchwarmer
Can you please look at the following YouTube video and tell me if this is the flushing procedure you recommended for my 2005 Civic (overheating)?

Thanks

 

The video didn't look like a 1.7 but the hoses are easier to deal with up by the head behind the thermostat housing . If you want to purge the engine remove the hose behind the head put a hose on the nipple and into some coolant mix , get a shop vac and suck out coolant without running the other end dry . I think the pocket sits by the water pump . A cheap thermostat can cause problems too you'll have to figure it out , I was talking today with a mechanic about the same thing and what a P.I.T.A. they are . If heat is a problem you can flush it out also before you go after the air pocket , coolant should be changed anyway it gets dirty and contaminated just like oil does .

 

The crack in the header is unimportant for now. JB Weld might seal it if you get in there and really use a machine to make a clean surface for it to adhere to, cut some diagonals with a hand tool, etc. Like pictured here (inside of a Toyota valve cover). But seriously, skip all that as the volume of air passing, pressure, simple physics make that crack unimportant for now.

If it heats up at idle/sitting, you have a powerful clue that in that scenario, engine heat is rising (given) and capacity to cool it is compromised. Have you verified fans are working? But biggest thing, have you sampled coolant to look for blow-by? simple look-see and posting pics is worth hundreds of words...

 

I agree, crack in manifold is not a priority.
It does not overheat at idle or while driven in town. My son drives it to college (12 miles round trip , at 0 to 40 mph, with no problem). Does not overheat either while driven on highway at 0 to 70 mph for 45 mn. It overheats after he exits the highway and slows down to a stop (he usually has the AC on).
I did do the coolant color test to check for a blown gasket (BTW AutoZone lends you the suction bulb test device and test solution for free). The test was negative (the color of the solution did not change). I will monitor the heater temperature and do the heater core flushing as u suggested.
I recently took it to Tires Plus and they told me the AC compressor tends to freeze sometimes due to a bad ac clutch, which may be the cause of the overheating. They proposed to replace the compressor and flush the AC system for $860.
I am a little warry because a number of times they gave me a wrong diagnosis ( like telling me i needed a new $2,500 transmission on a minivan when I only needed a speed sensor which cost me $60 which I replaced myself).
Thank you

 

I don't know this car really at all, but have lots of experience on other makes. Thus, nothing I say is authoritative.

One time I saw a problem like this - and it was odd. The thermostat was installed backwards (easy to do in some housings). The bi-metallic valve could open, but not fully. It would behave VERY similarly to what you describe. Do not know if that's even possible here. It could provide enough cooling for short periods, but then when full cooling was needed, it could not deliver it. So when you leave the highway and the airfflow drops from 60mph go zero, you could get this.

That oddball situation aside, Two other things come to mind:

1) You could have a partially clogged radiator. It would be adequate at low speed or with adequate air flow, but not when hot and stopped.

2) Bad fan or temp. sensor that is not activating the fan.

I'd look into those things if not already ruled out.

 

I don't think the car knows whether it's on a ramp , red light , or wendys' drive through . You can assume this happens at random times once vehicle is warm from one component failing . That's why I don't like a cheap stat. a bad one can cause those symptoms . Th one 04 civic I have would do the same kind of thing .

 

Hi Benchwarmer
I have replaced the thermostat but it wasn't OEM. I might just get an OEM one to make sure.
Thanks

 

Thanks Civvy66
That is interesting. I plan to put a new OEM thermostat and make sure it is installed correctly.
Thanks

 

You can test the thermostat really easily. Put it in a pan of water and boil it. Set a meat thermometer, candy thermometer, etc. in there, too. It should open around 170F (allow for imprecision so as long as it's close, it's good). Even if you don't have a thermometer, you can just see if it opens around when the little bubbles are forming on the bottom of the pan and before it boils hard. Anywhere in there would indicate the thermostat is working OK.

 

Thanks for the test tip Civvy66! I will run the test and let u know.

 

If you keep having problems I would but if not then why bother , I've seen thermostats last years , and I've seen them last months , nobody wants to test a stat in a pan of water once you start having problems . I think you may as well replace it then once you have it out . I spent $40** on one but I'm confident it'll work right . You can get them for $6** but you can't get a sandwich for $6** so I'd have to think it's a P.O.S.

 

Benchwarmer
In the process of pricing a new OEM thermostat for my 2005 Civic 1.7 L, I found out the one I had replaced back in August (19301-PAA-306) does not fit my car (Darn!). Could this be the cause of overheating?
One dealership told me the correct part I need is 19301-REA-305( $43) ; another dealership told me it's 19301-PLC-305 ($81). Both are OEM.
​​​​​

 

The dealership sold me a 19301 PLC 315 , 202F1 for a 2004 civic with a 1.7 for $43** , maybe go on line and see , there should be honda parts OEM available , why the discrepancy I don't know .