ang1dust

New to Forums,
Spent the better part of 2 hours looking over what was written and i cant seem to find my issue. Maybe i am overlooking it so here goes.

I have a 2005 Honda Civic Sedan EX 1.7L (Vtec - least thats what it says but its not that fast for a vtec) with 95k miles. Never had a problem with it, always taken to honda for service.

Recently i experienced the temperature getting hot while idling with the AC on. I checked to see if the fans were going and they were. After accelerating no more than 10 miles per hour the temperature dipped down faster than a gas guage when filling up at the pump. So i got home, let it cool and topped off the water and reserve.

A day later, about 200 miles or so, it started overheating at idle again. Turned AC off, let it idle and fans wouldnt come on. I thought BINGO, that was easy. Tested the socket by jumping the switch and fans instantly turned on. Lets go get a fan switch. Put the fan switch in, purged and topped off water but 3 days later it started over heating again.

I pulled over and put my finger on the fan switch and held it there for over 20 seconds as it was overheating. Anyone see a problem with that? I did...a normal engine idles 210 ish give or take someand it would burn my finger.

So when i got home, i drained all the water, removed the thermostat and tested it. It was working at 180 degrees on the dot. I decided not to put the thermostat back in and put only water in for now to save money. Instantly at half way marker the fans turned on!

Now this makes a person wonder. If the thermostat tested working (it was replaced during alll this btw) but it doesnt seem to open up in the thermostat housing to get the fan sensor hot then the water isnt getting to the thermostat.

Lastly, with the thermostat out for the remainder of the troubleshooting i topped off the car with water and let it idle with the AC on for 30 minutes and it would not over heat. I then turned the AC off and idle for 30 minutes it would not over heat. Ok so what changed?

I changed nothing, i did inspect all the heater hoses and cooling hoses to radiator and everything seems beautiful to say the least. Nothing even close to needing replacement. No signs of water leaks asides the splashes of water from draining and replacing it from before. So later i get on the road and no more than 8 hours later its over heating at idle again.


It seems that it is only over heating after acceleration. So, im at a loss. The radiator seems to have flowing water during idle so the radiator is good....reservoir has water...no signs of water in the oil....no smell of exhaust in the lines or oil in the water or gas in the water...no smoke from the exhaust and no loss of power....what am i missing here?

Thanks in advance

go-part

http://www.tegger.com/hondafaq/overheating/#speedtop

ang1dust

Good information. I have seen it. I appreciate your response. Would love some possible input if anyone can provide it.

Matt_75

You sure seem like you're topping the radiator off a lot. Is the reserve tank filled to the max line when you have the overheating issue or is it filled to the top where the cap is? Is the radiator low when you pull the cap off to refill it? Have you tried to burp the car on a hill or with the front jacked up? Both the upper and lower hoses are hot?

Worst case scenario, If you don't have any leaks and you keeping loosing coolant, there's a possibility your head gasket is blown. And no, you will not see water mixed in the oil. This is a common issue with this generation of civic. I would use the method in the link below if you can to test each cylinder. The guy who wrote it knows his stuff and is a honda dealer tech.

https://www.civicforums.com/forums/p...54-post10.html

ezone

I don't remember a damn thing.



Post the video that scooty(?) made with the overflow hose stuck in the bucket. Or a link. I didn't find it (again).

Matt_75

Don't worry. I got your back.

https://www.civicforums.com/forums/1...ml#post4629441

ezone

Thaaaaats the one! Thankin' ya kindly.

BlueEM2

iTrader: (1)

Are you bleeding the coolant system properly when your doing this? Don't use water, use only OEM HONDA COOLLLANTT AND NOTHING ELSE IN THESE. It honestly sounds like you just have air in the system. The fact that your always topping it up screams to me air in the system... Not head gasket (YET)

johndeerebones

Yes it does scream air, but coming from where :P

ezone

BlueEM2

iTrader: (1)

Hmm... looking into the ball.. I seee...... hmm... a ball?

ezone

I see some dude in an oversized hoodie with a bad Santa beard on.

dakota1820

Drain cooling system, remove temp sensor and pour antifreeze mix in. Once coolant starts flowing out of the temp sensor install temp sensor and keep filling start car with heater on and top off if necessary. This imo is a great way to bleed the system.