Coolant level 1'' higher???

[goldNSX]

I went for a very spirited drive yesterday and have seen that the level in the coolant bottle is 1 inch higher as before even with a cold engine? What's this?

 

[slamstrom]

Sometimes when the radiator is really hot (especially with the AC being used for a long time) the coolant will expand and overflows into the coolant reservoir. However, when the radiator cools down, it should suck the overflow back into the radiator. I noticed this on all my Hondas. Have you checked your coolant reservoir level today?

 

[goldNSX]

It just looks to me that it expanded but didn't suck back. Or it's air in the system by whatever reason. Headgasket? No overheating till now.

 

[OLDMNSX]

"Gold" I have marked my coolant tank level for both "Cold" and "Hot". They are about 1" different, with the hot level being the higher of the two. I used a black "Sharpie" permenent marker and made a line about an inch long (26mm) at the level.

I would really doubt that you have gained any air in the system unless you have noticed coolant on the floor of your garage.

How old is the coolant tank cap?

Do you remove the coolant tank cap to check the "Cold" level. I remove the cap and shine a "Maglite" flashlight into the coolant tank filler and shine it to the side to see the exact fluid level. This method doesn't work for "Hot" so just put the flashlight up against the side and move the flashlight up and down till you see the top of the coolant.

Brad

 

[goldNSX]

"Gold" I have marked my coolant tank level for both "Cold" and "Hot". They are about 1" different, with the hot level being the higher of the two. I used a black "Sharpie" permenent marker and made a line about an inch long (26mm) at the level.

I would really doubt that you have gained any air in the system unless you have noticed coolant on the floor of your garage.

How old is the coolant tank cap?

Do you remove the coolant tank cap to check the "Cold" level. I remove the cap and shine a "Maglite" flashlight into the coolant tank filler and shine it to the side to see the exact fluid level. This method doesn't work for "Hot" so just put the flashlight up against the side and move the flashlight up and down till you see the top of the coolant.

Brad

Yes, I did the same, marked it cold and hot. Coolant cap and bottle are 1 year old, easy to see where the level exactly is.
Tomorrow I'll go to my mechanic an we do a CO-test to the coolant. This should make things quite clear I hope.
Today I did another test: Cold level was 1'' lower than yesterday hot. When it got hot it reached the same level as yesterday. I opened the cap and watched for air bubbles. At idle there were nearly to none bubbles. Pushing the gas by hand showed some amount of bubbles in the bottle with the coolant level rising. The engine runs fine, no water in the oil, no white smoke out of the exhaust, no noise, no false ignitions and the car still pulls very hard, temp gauge still one mark below mid. It's just the annoying coolant level that is much higher than before.
I still guess it the head gasket in a very early state of defeat and this happened right after my 166 mph test on the German autobahn. Taking it to the worst case it's hair line in the cylinder head. I know of two other cars that had the same defeat, 3.0 with the crappy Honda head gasket.

Thanks for your input.

 

[OLDMNSX]

Tomorrow I'll go to my mechanic an we do a CO-test to the coolant. This should make things quite clear I hope.

I am not familiar with this CO test, what is it?

Another thought, with the system completely cold, have you checked to see if you get any air out of any of the bleeders? Just a thought.

Brad

 

[goldNSX]

I am not familiar with this CO test, what is it?

Another thought, with the system completely cold, have you checked to see if you get any air out of any of the bleeders? Just a thought.

Brad

A CO test looks for leaks, esp. exhaust gases in the coolant bottle. MY TEST WAS NEGATIVE (god bless my NSX).

A flush of the hole system was recommended and I'll do this while changing the coolant hoses the next few weeks.

Thanks,
thomas

 

[goldNSX]

A picture of how the coolant level looks like: 12.8. and 13.8. are dates, kalt = cold, heiss = hot. As far as I can see is that the level sinks a little bit over time but the hot level has never been so high. I once has been higher than the highest level noted on the bottle.