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2004 Honda Odyssey

2K views 13 replies 5 participants last post by  Buffalo4 
#1 ·
I'm looking for advice on my 2004 Honda Odyssey. It has 183k miles on it. It's been overheating when driving and running the a/c but once turned off it doesn't overheat. Sitting parked for half an hour with a/c running, it doesn't overheat (was trying to replicate problem in front of my house). Thermostat, timing belt, water pump and 3 ignition coils were replaced a few months ago. Not sure if this is relevant but a/c has been making a loud buzzing noise. Thermostat was replaced because it was overheating then too. Worked fine for a few months then started up again. Transmission flushed and air filter replaced last week. What could possibly be wrong? Faulty thermostat or does the radiator need to be replaced due to age/mileage?
 
#2 ·
Have you checked the operation of the radiator fans?

How often did you change coolant on the radiator?

The buzzing - is it when you turn the blower motor up? If so, just debris in the blower motor.

Something blocking or inside the air intake?

Others with more insight will chime in, but that is a start. Use the google custom search box and you will find some answers as to how the fans should work and how to fix the blower motor.
 
#3 ·
It sounds like you are not getting sufficient coolant flow when the engine is putting out more heat(driving down the hwy).
If the coolant level is proper and you aren't losing any, I would guess on a thermostat not opening wide enough (common problem with an aftermarket thermostat) or a partially clogged radiator.
Easiest thing to try is replacing the thermostat with an OEM one.
Since it doesn't overheat at idle with the AC on, then I would tend to believe that the fans are running. Do both fans come on as soon as you turn the AC on?
Buffalo4
 
#4 ·
I just took it somewhere to get the codes read and reset and they said 5 ignition coils are bad... which means the three I just replaced are no good. What causes that to happen, maybe the new ones were no good? (I purchased them from 1AAuto) Both fans run when turned on. I'm going to go ahead and get the radiator replaced since I've seen it mentioned on here and elsewhere that it should be replaced after so many miles/years. The thermostat was purchased from the Honda dealership, and the radiator will be too. What other replacements/maintenance is required at this age/mileage?
 
#5 ·
CEL on with bad ignition coil usually means you are getting misfires. What codes came up? Is your engine running erratic before and after the T-belt repair?

Clogged radiator usually is due to neglect of the cooling system. Never changed coolant or used tap water or debris contamination. Rusty color coolant is one indication.

You can easily check the condition of the stat by putting it in boiling water. My 13 dollar AZ stat and american eagle-ebay radiator has been performing great - as it should for the past 3 years. No issues.

It is possible that the new water pump that was put in there could be defective. Do you know what it is? Did you see/inspect the old water pump? Are you sure the old water pump was actually replaced?

The cooling system and the coil codes are separate systems. The coil can't cause the cooling system to overheat. But an overheated engine can fry the coil.

Look at your stat and water pump. Good luck. Is this a newly acquired vehicle?
 
#6 ·
You probably have 1 coil that is still bad causing extra codes on other cylinders. That is common. Some folks have issues with aftermarket coils. As mentioned, that wouldn't make the car overheat. What exactly is the symptom you are seeing, gauge going way up? Make sure there are no air bubbles trapped in the system.
 
#7 ·
I also seriously doubt that 5 coils are bad. The code can be misleading in that if one coil is bad, it can show misfires in multiple or all cylinders. It is fairly easy to check by disconnecting the low voltage connector on the coil while the engine is running. If the engine doesn't slow down or run rougher when that coil is disconnected, it is probably bad. Do one at a time.
Buffalo4
 
#8 ·
On my Ody, the car would get up to around 220F on my Ultragaute while driving at 70+ down the highway on long trips with the outside temps in the upper 90's. If I downshifted (out of lockup) so that the rpms increased, the temp would drop very quickly. I had installed an aftermarket thermostat and it didn't open as much as the OEM one. I put an OEM one in and the problem went away. So, if the thermostat in your Ody is not an OEM one, that MAY be your problem, and not the radiator.
Buffalo4
 
#9 ·
Thank you for all the replies. The thermostat is OEM since it was purchased directly from the Honda dealership where I originally purchased the car new in 2004. I honestly can't tell you what the codes were saying since my husband takes care of that. It's my car, and I just know what goes wrong with it when I'm using it, but not all the repairs/codes. Months ago the engine was heating up so the thermostat, water pump and timing belt were all replaced, and a few coils were as well. This didn't get rid of the lights in the dashboard as I was told it needed more coils. It stopped over heating for a short time until almost two weeks ago. At that time I took it to get the transmission flushed and air filter changed. It worked fine for about a week and then overheated again. Today my husband took it and had 3 coils replaced since we had 3 on hand and replaced the radiator with a new one from the dealer. I drove it around for a few hours today with no problems, no more overheating, no more lights on in the dash board. Hopefully this fixes it for good now.
 
#14 ·
Have the engine coolant tested for combustion gases.
Perhaps there is a head gasket leak.
Even OEM thermostats fail out of box, but not often.
Make sure the battery connections are clean and snug. Same with the bonding jumpers (one from the neg post of the battery to the frame and one from the frame (near the top of the radiator) to the engine. Also have the battery checked.
Check that the radiator fins are pretty clean of debris, perhaps a plastic bag, etc got caught up in there.
All those ignition coils failing is a rarity and suspect.
Codes can be very helpful.
Buffalo4
 
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