LuckyBoy

I know this is a topic that has been covered by others with similar problems, but I've been reading others threads for three weeks and I just want to explain my personal experience and get some input.

My 2003 EX/MT is having weird intermittent cooling issues. This started about three weeks ago after a solid year of flawless duty in my ownership. It began when my temp gauge started fluctuating semi-randomly. Sometimes it would go up a few notches while driving, sometimes it would raise up while idling. It would usually cool down as I was driving, so I thought: fan.

Replaced the fan switch, bridged the fan connection and checked motors, checked relay. Fan kicks on fine.

Problem continued. Random temp climbing, sometimes while idling, sometimes driving. Sometimes I would idle for twenty minutes and it wouldn't climb until I drove off. Other times I would idle it up and temp gauge would be 75% toward the H and it would -immediately- drop the needle to proper temp when I drove off. Thinking maybe thermostat.

I replaced the thermostat and the problem actually got worse. The car was damn near undriveable the next night (after a day of driving) it was climbing pretty close to the H and doing it far quicker. So I though I had an air pocket in the system.

Bled the system as best I could and refilled the coolant. Ran perfect for about two days, then same intermittent temp climb came back.

Bled the system again, this time doing everything by the book, revving the motor and slowly pouring in coolant as the level sank. Drive fine for another couple days including a HOT three hour drive to Daytona for SBN and back in the same day. Not a single temp variance. Lots of stop and go traffic in the heat, fan worked as it should.

Then today...two days after the Daytona trip with no issues. Out of nowhere, I get in the car while it's idling and it's 75% up the damn temp gauge again. Cools off while driving away but still runs a half-a tick mark hotter than it was the other day. Come to think of it, it was running that half a tick hot last night as I was driving home as well. So I let it cool a bit, popped the rad cap and added about 16 oz of water. Drove it with no cooling issues to Discount Auto and bought another freaking gallon of coolant and got a referral to a local mechanic.

Drove it about 15 minutes to the mechanic, no cooling issues. Told all of this to the mechanic and he scratched his head. We checked for the usual signs of head gasket leak and none were present.

I changed the oil before Daytona and no coolant in it. No white smoke. No dripping water from exhaust. No coolant blowing from the rad cap when revving the motor. No funk on oil cap. Two mechanics so far swear that it's not the head gasket.

I told the mechanic that the only things I haven't tried are the actual temp sensor and the new radiator cap that I bought (because when I put it on it was blowing steam everywhere for some reason) so he told me to try the new radiator cap and add more coolant (again.)

I drove the car home with the new rad cap on it. It drove fine, no spikes. I need my car for work and this is getting very tiresome. The problem alone is a pain, but spending every day watching the temp gauge waiting for the freaking gremlin to come back is stressing me out more than you can imagine. I have the option to trade this car in, which i'm going to have to do if I can't nail the problem down. But I don't want to because I'm ONE WEEK FROM PAYING IT OFF! Figures.

To recap:

Temp climbs almost randomly, more so in idle but not always. Sometimes drops back down just as randomly, sometimes keeps climbing.
The heater ALWAYS stops blowing hot air before the temp gauges starts climbing. That's why I thought it was an air pocket. It seems like the car will run perfectly for about three days each time before the temp gauge starts climbing. The major constant is that each time I fix the problem, I add more coolant and bleed the system. This makes me think I have to be loosing coolant, despite the lack of noticeable leaks.

No signs of head gasket problem. At least not a major one.

I've replaced: thermostat, fan switch, rad cap (as of ten minutes ago)
I've checked: fan relay/motor, bled cooling system several times, radiator is flowing.


The last mechanic said to try driving with the new rad cap and see if that helps. He said that even though there's no signs of head gasket problems, I might have such a tiny, tiny leak that it's fooling the tests. He suggested that I get these little pills that they make for aluminum block cadillac motors that you crush up and put into the radiator. Supposedly they seal up tiny leaks in the head gasket. I have also seen a product called Steel Seal that can seal up even major head gasket leaks (supposedly). I'm willing to try these if it could end this fiasco.

If it ends up being the head gasket or water pump, I'd rather not sink money into fixing a motor that has 150k+ miles on it when for less than $1000 I can drop a barely broken-in salvage motor in the car.

If anyone can offer some advice, please...I'm losing my mind.

ExistEvolution

How many miles and have you had the water pump looked at? Any of these mechanic do a block check/test on it see if exhaust gas is getting into the cooling system.

ashley4285

I am having the exact same issue with my 2003 civic ex with 87000 miles on it. I just had the thermostat replaced this week and it was fine for a few days but today it started again but worse this time. I have no idea what the issue is. I am loosing coolant but its not a lot of coolant. Have you figured out what is wrong with your car yet? I would love an idea of where to start with mine. Thanks!

xRiCeBoYx

iTrader: (22)

Try flushing your system as well.. I had some random overheating problems before and what I did was replace the radiator cap, flushed my system, changed the thermostat, replaced the coolant, and I haven't had a problem since

gearbox

iTrader: (95)

first find out where the coolant is coming from.