Overheating

[Oldacura]

MikeD & others -

I have read up to page 60 on the Legend Forum on the thread about overheating. The thread is now over 120 pages. I’m writing to you because you and others seem to have the best understanding of what’s going on and you are quite helpful.

I don’t know if you still have your Legend because some of the posts were several years old. If you can help me, I’d appreciate it.

My story: 1995 Legend LS. Bought summer of
2003 with 90k miles. Now has 130k miles. I am the 3rd owner. I have been following the Legend Forum most every day. I have been very careful about overheating issues. About 4 years ago, I noticed a hairline crack on the top radiator tank near the throttle cable bracket. I replaced the radiator, most major hoses, thermostat, fan temp sensor & refilled w/Honda coolant. I bled the system carefully as described by you and others on this forum. My temp gauge has always been rock solid at 3/8 scale. I have checked the coolant level in the overflow tank regularly. I almost never had to add coolant. Most of the miles I put on the car are commuting back & forth to work. 20 miles each way. Easy driving. Not fast, not stop & go.

At some point in the recent past, I heard some gurgling from behind the dash. I recall that after that, I had to add a bit of coolant to the overflow tank & bled the system.

3 days ago we had a bit of cool weather. I was driving home with the heat on & though the gauge read normal, no heat. The gauge would then rise & the heat would blow warm.
The gauge never got above 5/8. When I got home, I had to add about 1/3 gallon of coolant (Honda 50/50) & bled the system.

Just prior to this I had made a trip to the mountains & was driving for 10 miles or so at 50 – 60 mph in 3rd gear (climbing a pass).

I have never seen any coolant on the garage floor or engine bay. I have never smelled coolant. No white smoke in the exhaust. No evidence of coolant residue below the radiator cap.

Where could the coolant be going? It seems to me that if I have a seeping HG, the exhaust would get pushed into the cooling system before the coolant could escape into the cylinder. I called a couple of auto parts places looking for hydrocarbon test kits or test strips as some on this forum have suggested but they don’t have any. Is it worth taking the car to a shop to have them do a HC test of my coolant and/or pressure test the cooling system to try to find a leak?

Thanks in advance for any help you can lend here.

John Ellis (oldacura)

Lafayette, Colorado

johnellis@epiloglaser.com

[Daniel-S]

The cooling system of the Legend is well designed and capable of sinking the heat of the engine - even if it is run under full load on hot summer days. There are few reasons for failure:

1. non-functional cooling pump
2. sticking thermostat
3. loss of coolant
4. steam or air where there should be coolant


Other brands like BMW used impellers made of plastics. These loosed from the shaft and caused overheating. The high quality pump used in the Legend is not known for this failure as it dies not use an impeller made of plastics.

A sticking thermostat is a major problem in all brands. In most cases, a defective thermostat stays open. In that case, the temperature of the engine is not reached. Sometimes it stays closed, which leads to an overheating engine in a very short time. It is recommended to replace these parts whenever they are abour six years old or if there is an issue with the cooling system.

Loss of coolant is recognizable if the coolant leaks to the outside of the radiator, the pump or other visible parts of the cooling system. It is usually *not* visible if the cylinder head is cracked (never read abbout this on a Honda, this is a known problem with VW TDI) or in the case of a blown head gasket. Only if the leakage inside the engine is very excessive (about 1 litre / 100km), you may see white smoke in the exhaust.

Air or steam in the coolant system always blocks the heat transfer as the weight force blocks the circulation of the coolant. Remember the partial core-meltdown in Three Mile Island. It is essential for the cooling system that it is filled with cooland completely.

What you heard in the dashboard was air in the heat exchanger. If you bled the system repeatedly and correctly, my guess is definitively a blown head gasket. The weak point is the sealing between the cylinder bore and the cylinder head. When the engine is running, the high pressure in the cylinder forces exhaust gas to leak in the cooling system. This leads to accumulation of gas in the cooling system and causes instable temperature and noise in the heat exchanger. The heater is weak as it is no longer supplied with hot coolant. In addition, the gas boosts the pressure in the cooling system to a point where the radiator cap opens to the coolant reservoir. You may recognize that the radiator hoses are under pressure before the engine is hot. In addition, coolant leaks into the cylinder when the cylinder has its intake period. This causes loss of coolant when the engine is running. When you stop the engine, the pressure in the cylinder is at atmospheric-level whereas the pressure in the cooling system stays high until the engine has cooled down. This enables the coolant to leak into the cylinder bore. If this leakage is excessive, the starter motor tries to compress the coolant when cranking up the engine.

I would replace the thermostat first, but the probability of a BHG is 99%. The hydrocarbon test is quite undependable. Often a waste of money. After it has cooled down, remove the soark coils and crank the engine for one second. Remove the spark plugs and check for coolant and color.

Mine is still all right with about 150.000 km now, but one never knows. If the head gasket breaks down, I will repair that myself. I´ve done major repair on the infamous GM X25XE (timing belt cracked, twelve new intake valves...), so it won´t be too challenging to replace a HG on a Legend. One big advantage of the Legend is that you don´t need to buy special tools to repair ist. In most cases it is not necessary to plan the heads. Just clean the surface with a scraper and very slightly (!) with fine abrasive paper.

You just need some material and about four days of time...

[MichaelKA8]

Yes, indeed, there is 99%, that your headgasket is blown, because water is not running out anywhere and the overheating ist coming, when already water is missing.
Only: You are sure, that there is never some water down the car? Never the less, I would look to the waterpump one time too: Maybe this is only steaming, not dropping out from the exhausting hole under the bearing.
But mostly, when the radiator was leaking and the owner did not realize it early enough, you will have problem with BHG.
I read, you already replace thermostat, radiator and most hoses and the water is not running out from engine, so it must go into the cylindres. At present, maybe you have no white smoke out from exhauster, because the lot of water leaking to the cylindres is not much, only a little. So the steam is hot enough, for you cannot see it.
Maybe, when you start engine with open radiator cover, you can see small bubbles, like in a lemonade-bottle, from exhaust-gases. Or you can have smell from the gases.
Or you can check the colour of your sparkplugs, maybe one of it has a white face from coolant.
I had this many years before with a Honda motobike, a CX500. The right headgasket was a little bit blown.
Nearly no water was missing, no white smoke, except of one situation: After fill up gasoline at the pump, will mean, after parking only some minutes and start-up again with warm engine, motorbike was stamping like only running with one cylindre and give a little steam out from left exhauster. Only for maximum five seconds.
The sparkplug from left cylindre was white, the other was ok.
For the last I checked compression and indeed, the left cylindre was a little lower, than the right one.
The reason from blown headgaskets at legendengines is following:
When the radiator starts leaking, it is not easy to realize the first time, because you cannot see it.
But there will be one problem: When you check waterlevel only by looking to the expansionpot = overflow tank, you cannot see water missing, because the level will be always same.
Normally: When radiator comes up to pressure, some water goes to the expansionpot. When become cold, a little vacuum will take back the water to the radiator. So you can see level "half maximum" at cold engine and "maximum" with warm engine.
Now, when there is leaking something: The engine becomes warm, the waterlevel is normally maximum, but when becoming cold, there will be no vacuum and the water cannot go back.
That way you can check the water level at the pot, it will be always the same, but inside the radiator already water is missing. Many times, people only realize, there is water missing, when already the heater stays cold.
For this reason I sometimes check waterlevel in the radiator too and I always look to the expansionpot two times: Hot and cold, so I can see the level correctly coming up and down.
Never the less:
Check sparkplugs, maybe one ist white, or brighter than the others.
Start engine with open radiatorcover, watching if many small bubbles, like lemonade are coming up, take "a nose", whether the smell is like exhauster gases.
Check compression, maybe one cylindre ist a little lower, than the others.
And look to the
When your car really has BHG, please don't wait to long with repairing, it can happen, what Daniel already wrote.
Or the lubrication-film in the cylindre will be washed from coolant.
Normally: Even it is many work and money, to change headgasket, it is worth to do it, because the car will run properly for very long time after doing the job.
Regards, Michael

[Oldacura]

Thanks for the help guys. It's odd that I have to look to Germany for advice on my car in the US. The US Legend Forum no longer has members that are helpful. Mostly they want to put big wheels on their cars.

Since these cars are at least 13 years old, most US owners are teenagers or in their 20s. Few have any real experience. The members with experience (especially MikeD) have left because they got tired of the arguing.

Anyway, if my car does have a BHG, it is minor right now. I've been checking the radiator & overflow tank every day lately (~40 miles/day). I haven't had to add coolant in a month or so. I'm afraid to have the BHG confirmed because I've heard estimates of $2300 US for repair. I don't think I have the tools or expertise to do it myself.

I love this car. I think it is one of the most beautiful cars on the road. Every time I walk toward it in a parking lot I think "that's a beautiful car!".

Again, thanks for the help. I'll just watch my coolant for now.

[MichaelKA8]

I love this car. I think it is one of the most beautiful cars on the road. Every time I walk toward it in a parking lot I think "that's a beautiful car!".

Yes, indeed!k1:
That's our reason to drive this car long time too.
Most new cars don't have the style and engineering like the old Legends.
2300 $ is very high price, but it is same here in Europe. They tell about prices about over 2000 Euro too.
But another calculation: When the car is in still good condition, you can drive it a long time again, after that repair.
But a new car, even second hand, is not to buy for this price. And another second hand vehicle will have the risk of some damages too.
So, let's keep on "Legending",
Regards from Germany,
Michael

[MikeD]

Hi John
sorry for not getting back to you, because I've just read your problem. Maybe I can help you a lil bit...

We all do know that our Legends tends to get the dreaded BHG whenever we have any problems what does have anything to do with...

• Failed Waterpump
• Failed Radiator
• Failed Thermostat

That are the most important parts and can cause the well known Overheating problem! So could read thy you have checked the other parts and they seems to be fine. Ok.

Signs Of A BHG? Typical symptoms of a BHG may have...

• Bubbles of air coming up into your radiator (remove cap before starting)
• Leaking Radiator
• Milkshake colored oil
• Rough running
• Overheating
• Coolant or oil running from head
• Spark plugs that have a green tint (if green coolant)
• White colored or sweet smelling exhaust
• White smoke of your tail pipe
• Loosing coolant through your overflow

So most items are check by you and doesn't have anything to do with your problem (if I'm reading your post correctly). Let's go further regarding BHG's...

1. A BHG will leave a dark smell in the radiator. And you will have high back pressure coming though your radiator cap. Take car to a radiator shop they will place a detector which is a blue liquid inside a "bulb" if the liquid turns yellow you have a leak.

2. A BHG can be detected in a variety of ways. One way is to note whether that part of the engine block is leaking fluid. This is difficult to determine since there are many other parts of the engine nearby that can also leak fluids, especially when a vehicle is parked in one place for more than a few hours. One of the best indications of a blown, or nearly blown, head gasket in most cars is when the cooling system appears to be malfunctioning. The cooling system's efficiency and performance can be directly affected by the quality of the head gasket.

3. Many of the symptoms of BHG's can be caused by some other problem in the cooling system without the head gasket being damaged. For example: A corroding radiator can send chunks of rust through the cooling system which take out the thermostat and water pump. If the thermostat is old, sticking and corroding, it can send those chunks through the system and take out the water pump or cause a blockage in the radiator.

4. In most cases you will either get water in your oil or oil in the water but water in the oil is most common if your oil is milk looking then that is probably the problem how ever you can blow a head gasket between cylinder and this is harder to tell but 2 cylinders next to one another will have low compression but this would require some testing and tools.

Note: Low compression does not necessarily mean a blown head gasket, but it's a damn good indicator if there is a sharp drop in compression on one or two cylinders with no drop in the others. Sometimes a BHG will cause a whistling or wheezing sound, but not always. It will not always cause water to enter the oil or oil to enter the water, but they are sighns to look for. Overheating will almost always occur due to the exhaust entering the coolant. Check your overflow bottle for exhaust smells. Watch for bubbles or overflow of coolant from the radiator while running the engine. Check for muddy gray looking oil or bubbles on the dip stick. Does the car idle rougher than normal?

Where could the coolant be going? It seems to me that if I have a seeping HG, the exhaust would get pushed into the cooling system before the coolant could escape into the cylinder.

Yep I think so too. Your car may have a seeping HG or maybe a cracked cylinder head that is allowing antifreeze into the combustion chamber. At low speeds this would cause a misfire or your car to run rough. A slight amount of coolant in the combustion chamber at higher speeds would not be noticeable. You should have your engine checked for a leaking head gasket. Do you know how it works? Please get back to me if you need help

BTW: While posting I remember reading something about "Steel Seal". If my memory serves me correctly it was Cole in doing her job to try that strange product at that time. Do you know "Steel Seal"? Right now I'm not able to find that link on AL.com, but I know to read something about it. Please don't ask me how I think about that product because I've never tested it

On a side note: Does your cooling fans still turning on?

It's odd that I have to look to Germany for advice on my car in the US. The US Legend Forum no longer has members that are helpful. Mostly they want to put big wheels on their cars.

Since these cars are at least 13 years old, most US owners are teenagers or in their 20s. Few have any real experience. The members with experience (especially MikeD) have left because they got tired of the arguing.

Yes that's true. It's been a long time where the AL Forum (with Matt as leader) was the right place. Today it makes no fun anymore. Just a few members are still over there and a lot of good friends are gone at that time. That's one of the reason why I'm not active over there Today I have my own Forum and I'm happy to help everyone

You know that you're always welcome here, John. Don't hesitate to ask for help k1:

[MichaelKA8]

Maybe you meaning this:
http://www.rxauto.com/
They advertise it for repairing blown headgasket.

@Mike: At my motorbike I didn't have water in the oil, or oil in the water, and Lukas with his KA9 didn't have too.
When already the liquids are mixed, it is already very unseal, nearly before enginedamage.

[MikeD]

BTW: While posting I remember reading something about "Steel Seal". If my memory serves me correctly it was Cole in doing her job to try that strange product at that time. Do you know "Steel Seal"? Right now I'm not able to find that link on AL.com, but I know to read something about it. Please don't ask me how I think about that product because I've never tested it

Ha, I've found it: See Steel Seal

[Oldacura]

Mike, Michael & Daniel -

The ONLY symptoms I have seen are:

1) Gurgling sound behind dashboard
2) No heat along with slight (5/8 scale) overheating - one occurance.
3) One time loss of coolant - about 1+ liter.

The only time this happened was after 2 trips to the mountains after I was climbing mountain passes at 50 - 60 mph in 3rd gear for 10 miles or so.

New radiator, cap, water pump, most hoses, new fan temp sensor, Honda coolant. Fans work fine. Oil looks clean (not muddy). Coolant looks fine (blue).
No white smoke from tailpipe. Exhaust does not smell sweet. No evidence of leaking coolant on the garage floor or within engine bay. Radiator hoses do not swell up.

This may be the early stages of a BHG. Maybe its a little like suspecting you have some disease and are afraid to go the doctor and get it confirmed.

Thanks again you guys.

- John

[MichaelKA8]

The only time this happened was after 2 trips to the mountains after I was climbing mountain passes at 50 - 60 mph in 3rd gear for 10 miles or so.

This only was happening one time?
I was thinking, this already happened sometimes.
Maybe after replacing the radiator, you didn't bleed it correctly?
You must bleeding with fully open heater, will mean temperature control from AC on 31°C.
The radiator cover must be open.
Then you must open the bleeding valve, behind the thermostat, until only water is coming out, then close it.
Engine must running, until the radiatorfan was running two times.
After the fan stops running the second time (it is really mostly two times), you can see many bubbles coming up in the radiator again. Fill it up and close radiator.
When this only happened one time, maybe you didn't bleed the heater, the gurgling nose was from water, bleeding the heater and pressing the air out.
Maybe, first you watch the waterlevel carefully the next time, when this only one time was happening, perhaps you have good luck.
The climbing with this low speed in D3 is not a problem, this is no hard work for the legendengine.