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Discussion Starter · #1 ·
I'm experiencing slow coolant leak on my 2009 Ody. The exhaust looks normal, so I guess the leak is not engine internal.

Being in Seattle, it's impossible to see any leakage on the garage floor due to rain 24/7.

Have anyone else experienced coolant leakage, or know what I should check ? ( I've got 40k miles on the odo, so out of warranty. The leakage is slow, so I'm in no rush. )
 

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I think I have the same problem. I don't see any fluid in the reservoir. Maybe I am just not see it. Anyway, bring the car in this week to the dealer.
 

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As well as looking at the exhaust lool closely at the oil. dipstick, in the oil fill hole for signs of water. Water in the oil will show up as sludge in these areas. Check radiator cap and hoses for leakage. Any connection in the cooling system is subject to leaking.
 

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Just a word of caution. Continuing to drive with a coolant leak may cause the system to fail to pressurize, resulting in a raised boiling point, resulting in steam formation and local hot spots, resulting a warped cylinder head and blown head gasket. I would plan to replace the rad sooner rather than later. (Also order and replace the upper and lower hoses and ATF cooler lines while you are at it.)

A new top-rated Koyo W0133-1609568-KCS is $106 bucks from Amazon:

Amazon.com: Koyo Cooling Plastic Tank Aluminum Core Cooling Radiator: Automotive


 

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I think I have the same problem. I don't see any fluid in the reservoir. Maybe I am just not see it. Anyway, bring the car in this week to the dealer.
Please let us know how much the dealer soaks you for the new radiator and "shop supplies."
 

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Discussion Starter · #6 ·
Hi, since first posting this post I've put on roughly 2k miles, and seen the coolant in the expansion tank move max 1 cm.

I've come to the conclusion my leak is related to the in-car heater. The coolant only moved when using the heater, and has been rock steady for 1k+ mile since last used.

Does anyone know where I should be looking to find leak related to the heater ?
 

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Hi, since first posting this post I've put on roughly 2k miles, and seen the coolant in the expansion tank move max 1 cm.

I've come to the conclusion my leak is related to the in-car heater. The coolant only moved when using the heater, and has been rock steady for 1k+ mile since last used.

Does anyone know where I should be looking to find leak related to the heater ?
In the floorboard of the van center between driver and passenger for the front heater, I'd have to check where exactly the rear one is but I imagine its likely tucked on the side behind driver's side sliding door. Such a small leak may be tough to find, however there is a device I have called a pressure tester, and you can put this on the rad cap opening and pressurize the system to say, a normal PSI of 14lbs, then leave it overnight and see what it reads in the AM.

FWIW, I'm in the middle of doing some work on my van and I ALSO noticed that the tank was dry. I had previously replaced the Alternator bearing which required removing the tank and fans, and I can't imagine that I did not have it back to spec level after I reassembled. Perhaps there is some air in the system from factory?? I'd keep a close eye on it, and both test it and drive it.
 

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Just a word of caution. Continuing to drive with a coolant leak may cause the system to fail to pressurize, resulting in a raised boiling point...
Doesn't that mean it results in a lowered boiling point?
 

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Doesn't that mean it results in a lowered boiling point?
Yes, the boiling point of water increases as the pressure increases.

P1/T1 = P2/T2
 

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Although I *detest* AutoZone, they do have a decent tool loan program. You *purchase* a radiator pressure tester, use it, then return it for 100% of the purchase price. It IS their tool loan program, I'm not just saying that to cheat the system.

Rent that, buy some fluorescent dye from them & the appropriate UV light (fairly cheap) then pressurize the system & look for the leaking dye with your light.

Most all plastic tank radiators (majority of them are these days) will seep for a while before cracking. It's hard to tell where the leak is, plus after cycling the dye through the system by running the van, then letting it cool, you can get in and around in places you can't easily get to when it's up to operating temp.
 

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Anyone have any update on their problem?

I went to the dealer back in May, they just add some coolant and ask me to come back if it leak. I checked it every week for a few weeks and didn't notice anything else. Fast forward to today, I just checked it, it is way less than where I noticed it last time.

Guess I will be bring it in again tomorrow.
 

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Anyone have any update on their problem?

I went to the dealer back in May, they just add some coolant and ask me to come back if it leak. I checked it every week for a few weeks and didn't notice anything else. Fast forward to today, I just checked it, it is way less than where I noticed it last time.

Guess I will be bring it in again tomorrow.
1. Keep checking coolant.

2. Drain some engine oil and send to a local lab for oil analysis.
Search to see if there is a lab in your area.
In my city, the people that did the engine oil analysis are the people that service CAT (Caterpillar heavy machinery such as Bobcat, Earth Digger etc.).

Long story short, I lost coolant, initially 1 cup/100 miles, then the loss accelerates to 1 cup/30 miles.

Turned out the cylinderhead aluminum casting was porous and it took 4yr/53K to show up and coolant leak ---> misfire cylinder #1, and #3, loss of coolant but no engine overheat.

Luckily this happened during the 5yr/60K power train warranty. Dealer replaced both cylinder heads, gaskets etc. etc. It cost me nothing but the real cost for this job is about $3500!

Anyway, whatever you do, get an independent engine oil analysis (just drain some oil from the engine pan), if you see coolant, then you likely have the same problem as I did.

I detailed the whole thing here:

http://www.odyclub.com/forums/52-2005-2010-odyssey/27718-coolant-disappearing-reservoir-2.html
 

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Does local mechanics do the analysis?

The leak is really slow. When they added the coolant back in April, it was at midway between max & min when the engine is cool. Now it is an inch below min.

probably add like 3000 miles to the car from then to now.

The car drive run just fine. I just came back on a road trip to Canada with it. No over heating. No vibration at any speed. able to pick up speed on an incline, etc.
 

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Only a laboratory does engine oil analysis. Try a Google search for "engine oil analysis". That will give you some leads.

A slow leak like this may be just a hairline spray only when the engine is hot and the coolant is under pressure. It may leave dried residue in the area of the leak, but it could also just blow away without touching down anywhere.

Look very carefully at all the radiator and heater hose connections. Also check the small rubber hoses that run to the throttle body, as well as the hoses running to the air intake box pre-heater, and lastly the lines running under the van to the rear heater.

As long as there is still coolant in the bottle, the cooling system will run normally. But it it goes dry, the cooling system may suck in air causing local overheating as mentioned above. Never let the overflow bottle run dry.

Last resort is to keep adding coolant until the leak reveals itself.
 

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This leak might just be that the hot water evaporated out of the reservoir. Check your fluid strength. It might just need some distilled water added.
 

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As long as there is still coolant in the bottle, the cooling system will run normally. But it it goes dry, the cooling system may suck in air causing local overheating as mentioned above. Never let the overflow bottle run dry.
Caution: Evan a small leak may prevent the system from pressurizing and this may lead to localized boiling, which in turn will lead to a hot spot and a warped cylinder head and a blown head gasket. Just because the coolant reservoir is full does not mean that you are home free. Watch your temperature gauge or Scan Gauge.
 

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Discussion Starter · #19 ·
Kicking alive an old thread, but have an update. Since my last post in May last year, the coolant level has not moved a mm. I think the initial leak was due to improperly fastened coolant cap ( or dirty edges ). I've put on 8k+ miles, and driven in plenty of cold weather since May, so feel pretty confident the issue resolved.
 
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