Not too long ago my check engine light came on and the code was P0401. To my understanding this has to do with the EGR valve. Around the same time if the car is sitting still with the AC on it will begin to overheat. Switching off the AC tends to remedy the situation unless it is over 100 degrees outside. The Catalytic Converter was replaced ealier today. And the AC system was recharged prior to the problem.

Any ideas towards the overheating issue would be appriciated. If you need any further details please ask.

The car in question is a 2000 Accord Ex 3.0 liter V6.

 

I might be wrong but any car should not sit still with AC on for long time.

 

Those sound like two unrelated problems. The EGR port(s) are clogged and need to be cleaned.

When overheating with A/C on, are both cooling fans running? Open radiator when engine is cool and make sure that it is filled with coolant.

 

Actually before the situation started to occur the car could sit long periods of time without overheating. The problem is it shouldn't begin to run hot in the Jack and the Box drive through or sitting at a red light.. I guess my mistake was not being specific as to the time it takes for the temp to start to crawl up.

My main question is would an improper functioning EGR valve cause the car to overheat or should I be looking at the radiator for the problem?

 

Thanks PAhonda I will look into that later today.

 

No, look at the cooling system.

 

Just a note if you get your radiator flushed in Spokan make sure they do it right. As far as can be seen there are no leaks but the radiator was low about a liter and a half. Left the car running for over 10 mintues at operating temp with the ac on full and it didn't begin to run hot. I feel kinda bad for not checking the radiator fluid when the problem started but I expected them to do their job. Will give it a couple of more "test" runs before I call it fixed though.

Both fans are working.

About the EGR valve, We are considering the Seafoam approach to cleaning the system out? Does any one have experience with this? Is it a good are bad idea?

 

Sea Foam rocks, as for the coolant it sounds like they drained the system and then just re-filled the radiator and called it good, so once it started to circulate in the motor it came down to the wrong level, and I think you're one of the first people that I've seen on here that lives anywhere close to me *L* I'm over in Kalispell, Montana (about 4 hour drive)

 

This has come up before. Unless you could somehow flow the SeaFoam through the EGR passages, it is highly unlikely to have any effect. The reason is the system is Exhaust Gas Recirculation. Recirculation means that exhaust gas is recirculated back into the intake system. So any SeaFoam would have to first pass through the combustion chamber, exhaust, and a small portion return in the EGR system. No "live Seafoam" is likely to survive.

Further, I've repaired several EGR systems, and the deposits are very tough and even pure throttle body cleaner takes a while to work on them. Mechancial excavation is the primary cleaning method.

Seafoam may clean the throttle body, intake manifold, and intake valves, but that is probably limit of it's effectiveness.

good luck

 

You should monitor the coolant level everyday for the next week or two to make sure that you don't have a leak.

My friend had an occasional leak and couldn't find the source, so I told him to flush the system. That acidic radiator flush removed deposits and revealed a leak in the overflow tank.