PamBinSD

I have had ongoing problems with my 2005 Honda Civic EX. I have 190,000 miles on it.

My car overheated a few months ago. The fan was not working because of the relay. I had to replace my radiator and thermostat. No other issues with overheating. I bypassed the relay so the fan just runs whenever the car is running. (This isn't the issue...but I would like to know if should I replace the relay or is it ok to leave it as is?!?!)

A couple weeks later my car was idling extremely rough and was having a hard time starting up. I was able to diagnose that....one coil was out so I replaced it and all the spark plugs. Then the issue reappeared. I assumed it was another coil so I just replaced the other 3. (I put a new starter in the same time I replaced the radiator so that is not the issue).

My car worked again for about a week and then the starting issue happened again. My car misfires when I start it and it shakes really hard. My thought right now is that I need a new timing belt (it is almost time for me to get another one...I already changed it around 100,000). Would this cause the issues I am having?

My car drives just fine once it starts up and runs for about 30 seconds. There is no lag when I push the accelerator and it isn't using more gas. There is no check engine light. I am puzzled. I don't have a mechanic I trust. One I went to said my head gasket was blown without even looking at my car. My head gasket was fine...just needed to replace the radiator and thermostat.

Any help is greatly appreciated!!!

ezone

I'd guess head gasket too, especially since it's been overheated.

I bet the cylinder(s) that misfires is getting taking in antifreeze after the engine is shut off, then gets its sparkplug wet with antifreeze at startup and it doesn't fire until it gets dried off.

PamBinSD

I don't have any symptoms of a blown head gasket. The oil is not milky. There is no white smoke coming out of my tailpipe. There are no bubbles in the radiator. I am not losing coolant. My car is not overheating at all (when I was able to drive it...I would drive it for more than 30 minutes, sometimes in traffic). There isn't coolant on the spark plugs.

Why do you think it is a blown head gasket? I really don't think that is the issue. Is there anything else you can think of that might be causing my starting problems? What if the timing belt is slipping? Wouldn't that cause starting issues/misfiring?

ezone

You have described (what I thought are) symptoms consistent with a wet or fouled spark plug.... Combined with the overheat event, that makes a head gasket breach a prime suspect.


Right. These typically don't happen when this particular head gasket blows. It's gotta be in really bad shape before these symptoms would occur.


There's at least a dozen different ways a head gasket can fail.

When did you check this?

You gotta catch it in the act and check it right then.

You would need to fire up the engine and have it misfire as you described.
Shut the engine off before the misfiring clears itself up.
RIGHT THEN you jump out and remove the sparkplugs and inspect them.
If any are wet, you need to figure out what liquid is on the wet plug: Fuel? Antifreeze? Oil? Something else? .......Maple syrup?



Because it's a pattern failure in this engine, plus you said it's been overheated.

Of course it's not the only possible cause of your symptoms, but it's a strong possibility.
You and 95% of the rest of the victims.
Figure out why it misfires upon startup.

A timing belt cannot jump in and out of correct time. It's either perfect or it's not.

Easy enough to verify if it is correctly timed or not.

PamBinSD

Thank you for your input. I will have a friend pull my spark plugs after my engine misfires, as you suggested.

I still have a lot to learn about cars and have been reading up. Which is why I asked a lot of questions. I appreciate you taking the time to explain all of that to me. I have a hard time trusting auto mechanics. Luckily my friend can help me with some of the basics and I will figure out what to do if it this turns out to be a blown head gasket.