Rep Power: 0

I have had this 2004 Honda Civic LX since 2011. It's my wife's normal car. It has 163k miles right now. At about 120k miles (give or take) in 2016, it had the head gasket as well as the timing belt replaced (mechanic did NOT replace the water pump, so it may be original). Thermostat and radiator were also replaced at the time.

The past few weeks the car has has intermittent overheating issues, almost exclusively from city stop and go driving. It isn't leaking coolant, however this all started when it "burped" some coolant from the overflow because the overflow was too full. Ever since then it overheats randomely but will be fine other days, regardless of how hot it is outside (I live in the south, so it's a bit warm this time of year). When I notice the overheating issue I also notice the heat and ac performance decreases significantly. The radiator fan also does not always kick on when it is actively overheating. However I have brought it to my mechanic (he's a new mechanic for me because I just moved to the area) and he claims he can't get it to overheat. He also says he pressure tested the system and there are no leaks. He can't recreate the problem.

I have seen the Guage get as high as 80% there to the H but I shut the car off before it gets any hotter. I have checked the oil and it seems fine at this time, I don't see any other symptoms of a head gasket issue. The radiator is also still full, so it isn't losing coolant, however i noticed a little bit of coolant stained on the top of the engine. I am leaning towards the water pump being the issue but that does not explain why the fan doesn't always spin when it is supposed to. The mechanic has replaced a couple of relays for the fan but he is adamant the fan is good. I am thinking of trying a different mechanic for a 2nd opinion. I have brought it there 3 times, and this 3rd time he didn't do anything to it, just left it idling for a couple of hours and nothing. Anyone got any ideas?

 
Rep Power: 222

Figure out where that leak on the engine is coming from.
have him do the test in here

https://www.civicforums.com/forums/3...reference.html

 
Rep Power: 224

I'm still awfully suspicious of the head gasket.

 
Rep Power: 367

headgasket again
was the head checked for eveness when previous gasket replaced?
change mechanic, yes
see the testing method on the link posted above

 
Rep Power: 0

To everyone, yes the head was taken to a machinist and made sure it was smooth when the head gasket was replaced. Is it possible air could be in the system? This head gasket is barely at 40k miles, that's what makes me a little weary pulling that trigger.

Also, may be of note, the I do see air bubbles slowly coming out of the radiator cap area when the cap is off and I'm running the car. When it burped that bit of coolant out (it wasn't a lot, and It didn't continue to leak after that) is it possible air is trapped in the system?

 
Rep Power: 367

again, do the test.

here, linked

 
Rep Power: 222

I'm going to guess non OEM parts are to blame

 
Rep Power: 224

And/or improper installation.

If you're worried about air trapped in the system, burp it again. Remove the rad cap, jack up the front end, run the engine. Top off the radiator as needed. If the bubbles don't stop, head gasket.

 
Rep Power: 0

Just an update, took it to a new mechanic, he replaced the radiator cap and thermostat. Car has been fine since, I even did the exhaust gases test on the radiator and that came up negative for head gasket. The smell of coolant from the engine area is less intense now.

Only thing i found that concerns me slightly is i checked the radiator level today and it wasn't at the top like I was expected. The engine was cold. I didn't check the overflow tank yet, due to visibility. I'll try to check it later, but I was expecting when Cold the coolant would all pool into the radiator making it full. Otherwise the overheating has stopped so far and the air conditioning has worked as it should, but I haven't driven it enough yet to feel super confident in this car.

 
Rep Power: 367

if it pass the test and the reservoir is not full and spilling coolant, you should be safe for gasket, so that is a good thing.

hunh, there were some reports that aftermarket thermo does not work well with hondas too, if you did not get a OEM and can't find other culprits, keep thermo as one potential issue

pulling back to radiator depends on having vacuum, if it is not spilling from reservoir, rad cap (new now, so skip for now)/hoses, see if where hoses are connected are broken or not.

Here, a not usual cause:
https://www.civicforums.com/forums/3...-rad-neck.html

 
Rep Power: 0

I did check the hoses prior to getting the new radiator cap and thermostat, they look good. And when the engine warms up they warm up as designed and get hot when the engine has been running for a while. I am going to run that engine block tester again, just for peace of mind at least. The coolant not being at the top of the radiator is really the only irregularity I have found since. I have not had it overheat since, but the car has only driven maybe 100 miles in the past week and a half. And we haven't gotten to the real North Carolina heat yet since it is only May.

 
Rep Power: 222

Bet it's going into the overflow.
did you do the test in the video?

 
Rep Power: 224

Low coolant level in the radiator is still in indicator of a bad head gasket. Exhaust gases push the coolant into the reservoir (eventually enough to overflow it). Coolant won't flow back into the radiator in this case. My money is still on the head gasket.

 
Rep Power: 0

Update, the car was fine and the coolant level was unchanged (radiator remained full and overflow was at proper level) for the past two weeks. Driving it just now it started overheating again. I didn't notice any leaks however the overflow level raised a bit. Im waiting for it to cool down so I can do the block test (again). When the car was actively overheating the fan had moments when it wasn't spinning. Whether I was running AC or heat the only way to cool the car down was to drive at highway speeds (its about 65 degrees outside, not even that hot). At this point im thinking what I am going to do with this thing, because along with the other host of issues it has im not sure if I wanna keep it. Or just stick some blue devil in there and run it until it cant run no more.

 
Rep Power: 367

did you do the test on the video?
get that first and find out