thrasherx

1998 Honda Accord LX

Issue 1: Low Coolant
In September, I checked my coolant level, and it was low by 3/4 gallon. Not thinking much of it, I filled it back up, let the fan cycle twice, yada yada. Around November/December, I started noticing the sound of fluids swishing around when I would start/stop or change incline (up/down hill). I checked my coolant level again. It was low by about 1/2 gallon this time, so I refilled it. The next time I drove it, I noticed that the car was having a hard time staying aroudn operating temperature. If I let it idle for 20 min, it would get there, but as I drove it, the temp would drop to close to the bottom tick mark.

What I've checked:
Visible leaks

What I plan on checking:
Pressure test cooling system



Issue 2: Random misfires (P0302, P0303, P1399)
In addition to this issue, I've had some random misfires. The CEL has come on maybe 4 times in the last 4-5 months. It's my understanding that it has to detect 3 misfires in order to throw a CEL. Each it's given me a P1399, along with one cylinder misfire code (P0302/P0303), and each time I've cleared it; allowing me to drive without much of an issue for another 2 months or so.

What I've checked:
Cylinder compression: All good
Oil in coolant: None
Swapped spark plugs for cylinders 3 and 4 when 3 was misfiring. The next cylinder that misfired was cylinder 2.

What I plan on checking:
?????????????????


Issue 3: Rough idle on start
This issue isn't constant, but more intermittent. It seems like it happens more regularly when my car is parked on an incline, with the front end up-hill. The idle usually smooths out after a minute or so.

What I've checked:
I've checked for vacuum leaks.

What I plan on checking:
IACV


Somehow I wonder if any of these issues are related. Any advice?

accord99power

Issue 1) Pressure test if you belive you are losing coolant. covered already. Check thermostat.

Issue 2) If you moved just the plug and not the wire and the misfire moved with it, the plug could very well be bad. The order that your counting may just be wrong. Check distributor rotor and cap anyways and clean off contacts.

Issue 3) run intake system cleaner, clean throttle body, fuel injector cleaner, check air filter and clean the iacv (check connections) sometimes this will fix performance issues if it works or not still have a cleaner motor then before.

this is stuff i would do. also is this a f23? 4 cyclinder?

thrasherx

Yeah, sorry... F23 4 cylinder automatic

Just out of curiosity... is it possible that there's coolant leaking through my IACV, and getting burned off by the spark plugs? My friend who's an ex-Honda mechanic suggested this as a possibility. It would explain the low coolant, misfire, and rough idle.

The IAVC is a PAIN to get off... the hose clamps are on there tight.

accord99power

I think you would have a more consistant missfire, also you stated the misfire move, leaking coolant into intake thats runs into all cylinder would cause more cylinders then just one to missfire. Thats my theory on it anyways.

thrasherx

It was a blown head gasket. The diagnosis was easy:

Remove radiator cap
Top off coolant to the brim
Start car

If coolant shoots out, that means it's a blown head gasket. Luckily, I'm friends with a good mechanic who did the head gasket, water pump and timing belt for < $1000.