jw0532

I have way too much coolant in the resevoir and wondering what may be causing this. Should I take some out? also I just bought the car and not sure what the last person has done to this thing. Says he changed head gasket and various other things. It has 135,000 miles on it. why would he change head gasket if it did not have problems? Also am getting a PO304 error code and the check engine light is burned out. Seems to rum good when not hot but as it heats up it gets a little rough at 40mph and 60mph.

Any help here would be great. I am not a mechanic so please be clear with what I should do.

pi1996

304 is a misfire in cylinder 4

TexasHonda

If you mean the level of coolant is increasing, either combustion gas is displacing coolant or oil is being added to coolant stream (usually easy to see). Missing suggests coolant is getting into No. 4 cylinder.

First need to determine if head gasket is bad. Pull No. 4 and check for dampness. I like to do a cold start and check the coolant for bubbles or steady increasing level. If yes, the bad head gasket is almost certain.

If coolant is good, level not increasing, then just remove a little coolant. Perhaps someone overfilled.

If head gasket is good, the check for bad plug or bad plug wire to no. 4. You don't say but this must be a 2.5TL since you say head gasket (not plural). Don't drive too much w/ missing no. 4 or you could damage your catalytic converter. Coolant leaking into engine will also damage the catalytic converter.

good luck

jw0532

Thanks Texas Honda, I am in SA tx.
you mean I just take the cap of the radiator and start the engine to see if there is bubbles coming up from a cold start like this morning?

How can the misfire hurt the cat converter? how do I know if the cat converter is already damaged?

Thanks for the help.

JJW

TexasHonda

You're correct about the cold start check for bad head gasket. If you get a geyser out of the radiator outlet, extensive bubbles, or oil, the head gasket is bad. A good coolant system and head gasket should show almost nothing during cold start, and coolant will only begin to move significantly when thermostat begins to open.

Misfire sends raw fuel into the catalytic converter which causes the converter to get very hot and may damage the converter element. That's why the CEL flashes when you have a misfire, to indicate that car should not be driven w/ this condition.

good luck

jw0532

On the cold start the coolant did not move or bubble at first then a minute later it started to rise slowly. I put the cap back on and shut the car off real fast. Is a 1-2 minutes too fast for it to heat up after notdriving for two days?

pi1996

all right, i did this test on my car as well.
i got few bubbles, well, i didn't see them rise because i was starting the car and not watching.. so when i got there i saw few on the surface.. also the level in the radiator began to rise pretty soon..

what gives?

TexasHonda

If the radidator is full, the level may begin to rise slowly w/i a few minutes. A slow rise w/i 2 minutes suggests shouldn't be cause for concern, unless there were bubbles.

A leaking head gasket should show bubbles shortly after coolant level begins to rise steadily and quickly. In worst cases, a geyser will erupt from the radiator when throttle is applied.

I've left mine open for at least 5 minutes w/o significant rise. My 2.5TL is warm now. I'll repeat this on my car later and post results.

good luck

pi1996

i think my thermostat is faulty.
the car takes too long to warm up..

TexasHonda

I tried this test last night on my 2.5TL w/ a completely full radiator and you will have to remove some coolant ( 1-pt or so) to run the test. I got a thin stream of overrun w/i 2 minutes and stopped the test. You'l need to open the radiator drain and lower the level before starting the test.

Purpose of the test is to check for bubbles in coolant and/or large displacement by gas. Bubbles should not be present in coolant and any significant bubbles mean hot exhaust gas is entering the coolant.

If no bubbles or massive displacement, then your head gasket is OK, and you have an ignition fault on No. 4.

good luck