mlandmann

I have a 2005 Honda civic ex with 70000 miles on it. It overheated in December, ran car up red high temp line. Honda dealer replaced hoses and radiator cap.
Car overheated again. Brought back to honda dealer where they replaced the radiator and thermostat.

After driving 400 miles the car overheated again. Brought to another Honda dealer who actually did testing. Passed compression test. Failed leak down test for cylinder no.1. Replaced head gasket (and all other gaskets), water pump, timing belt, all hoses. Also had head resurfaced and valves tested.

Drove car approximately 830 miles and it overheated again.

I am at a loss for what the problem could be. I thought I had ruled out head gasket by replacing it. I do have wet/mildew smell in my car, which leads me to possibly believe that there may be a very small leak in the heater core. This could be BS though.

I also read in one post that it could be an "rpm sensor". The guy in this post seemed to have a very similar problem.

https://honda-tech.com/forums/honda-civic-2001-2005-78/01-civic-intermittent-overheating-2339016/
Any Suggestions?

tonykdee

wow sorry to hear. did you pay everything out of pocket?

i unfortunately have no input for you. sorry. but good luck.

Rone811

I just got done with this problem. I drive a civic ex se with like 73000 on it. Drove the car to monteray bay and it overheated, change the thermostat a week or so later overheated again then changed the fan switch. It overheated again and then took it to the dealership: (i tested the thermostat and the fan switch before changing them out and they turned out to be faulty)

-Dealership: Took apart our engine took off the head gasket then they machined the cylinder head down so they were flat due to them being warped. Re-applied fluid, burped the radiator and did an oil change. 1200 dollars later everything is running fine, but still keeping an eye on everything.

iplayloudly

fan clutch maybe?

If your heater core was leaking, you would probably smell coolant inside the car.

toyomatt84

iTrader: (1)

The fan isn't belt driven.

Alfspeed

I had the same problem and I repair 1 radiator fan, and the problem was fixed, check if the two fan are working, good luck

dabflyboy

does the "Lemon Law" work in cases like this?

robb_in_hou

I am having this problem with my '04 Civic. It overheats intermittently. When I am sitting at a red light, very once in a while, I notice the temp needle start to rise from its usually very stable mid-point. As soon as I notice it I roll down all the windows; turn the heater on full blaster; and put the car in neutral. But the air doesn't get hot and the temp continues to rise. When I take off the air gets really hot and the temp goes down.
That is why I thought it was the thermostat sticking so I replaced it. No joy.

As long as I keep my speed up the temp is OK.

This time, I got it home and the needle was about 3/4 up the temp gauge. I popped the hood and neither of the fans were on. I'm not sure which is which but it doesn’t matter; I didn't have the A/C on but at least one should have been on. I put 12 VDC to each fan and they work.
That is why I think it is the coolant temp sensor.

I'll try that this weekend.

grabanks

I'm interested in this unexplained "mildew smell". . . I have this problem and have shampooed everything, searched for any area of wetness--all with no luck and continued smell. I agree with the poster that heater core leak would add the smell of anti-freeze--I don't smell that. When I change the cabin filters, I sniff the old filters and the area where they live--no mildew smell there. . . I go out after a hard rain and try to find water inside the cabin, but there is none. Anybody else smelling this?

pw.hondatech

seeping head gaskets for no apparent reason are not uncommon on that engine.no,the lemon law is for cars still under warranty.if you do a headgasket make sure to have the head milled and use copper coat.

AutoXer

Mildew smell with the A/C on is usually caused by having mildew in the ducting. They make a spray (forget the name) that you can spray into the intake at the bottom of the windshield with the system running. I've used Lysol (unscented) and it does the same thing, just takes alot more volume to kill it all off.

For the overheating, if it's doing it at all the time, it's likely a cooling system problem (t-stat, headgasket, etc.) Overheating while sitting but not while moving is a problem with the fan, fuse or fan switch.

jasrams

funny enough i had a problem similar to this and i tried everything even tookout the computer and got it tested to see if something was wrong still overheated when i finally found out what the problem was it was a stupid fuse that was blown and it wasnt the fan fuse apparently honda have cross fuses so when i checked all and replaced all fuse especially the one that controlled the windows and sunroof it stopped correct me if im wrong

boss em2

head gasket blown or head is warpt

lebpharm

I am having exactly the same problem
any idea how to fix it?

and another thing, is it normal for the fans to go on for 1 min and then off for 30 seconds then go on again, alternating 1 min on then 30 sec off? even if the temperature needle is 3/4 up? or it should be ON continuously until the temp goes back to normal?

chris11057

I had the same problem for a bit too. Not completely sure if its fixed. I was losing fluid while driving long distances for some reason. I had the radiator cap replaced and it did the same thing a couple more times that day during a cross country drive. after that its been fine and its been about 2 months. let me know how you fixed this if you do. good luck