Cooling/Radiator/Hoses

[goldNSX]

I noticed yesterday that the coolant level of my NSX is a little bit low. Besides that I'll think about revising the cooling system based on your suggestions. It's a 91/55000 miles with a new waterpump in 2001. The hoses, radiator, expansion tank etc. have been untouched I think.
What's your opinon: Changing all the hoses/only selected ones, changing expansion tank, other parts? I'm specially interested in leaking radiators as the AutoBild Tuning of 11/2004 stated that older NSX's may have a problem there.

Thanks in advance,
Thomas

 

[zanardi 47]

If a new waterpump was installed in 2001, I wouldn't be suprised the coolant level to be low. This is assuming a few things ...
1) the coolant flushed/filled when the water pump was changed
2) you have not added any coolant or demineralized water in your expansion tank since 2001 ...

I do strongly recommend using the Honda premixed coolant (part number OL999-9001). The service manual states, the following: "The first coolant replacement should be done at 36months or 45,000 miles (72,000km) by your dealer. After that, it should be replaced every 2 years or 30,000 miles (48,000km). "

As for the cooling system components, I would change the following:
- hoses/clamps: assuming it has not been changed since 1991). Go through the cooling circuit and make sure you catch those rubber hoses and clamps. These are not very expensive components (relatively speaking), as you are getting a coolant flush and fill, it would be a perfect time to change out the components after you have drained the coolant system.

Inspect the following:
- expansion tank: are there signs of leaks???
- radiator: this is tough to judge ... but look for signs of leaks.

I hope this helps ...

Richard

 

[hlweyl]

I'm specially interested in leaking radiators as the AutoBild Tuning of 11/2004 stated that older NSX's may have a problem there.

I don't know what autobild tuning is, but I don't think leaking radiators are very common among us NSX folk(not to say it's impossible). The only time I've heard of someone replacing the radiator are folks who primarily track their car and looking for slightly better cooling.

 

[goldNSX]

If a new waterpump was installed in 2001, I wouldn't be suprised the coolant level to be low. This is assuming a few things ...
1) the coolant flushed/filled when the water pump was changed
2) you have not added any coolant or demineralized water in your expansion tank since 2001 ...

Hi Richard

My car is kind of overserviced, the coolant was changed this year. So I'm not sure if they had filled it completly up as it is quite different to avoid air in the NSX system.

The other question is: Shouldn't be the coolant system a closed system? I mean if something is missing then there MUST be a leak?

Greetings,
Thomas

 

[Enzo]

Hi Thomas,

FYI, I had the same problem, some years ago, on my NSX ! The coolant level was low and we found that it was due to one very small crack in the coolant bottle.

 

[goldNSX]

Hi Thomas,

FYI, I had the same problem, some years ago, on my NSX ! The coolant level was low and we found that it was due to one very small crack in the coolant bottle.

Hi David!

Thanks for your information. It's good to know in which direction we start to seek. How low was it? Mine is about LOW-LEVEL now starting to frighten me.

Greetings,
Thomas

 

[Enzo]

Does your NSX overheat when you are stuck in a traffic jam ? For me it was the case !

 

[goldNSX]

Does your NSX overheat when you are stuck in a traffic jam ? For me it was the case !

The water temp is in the normal range (1 line below horizon) and doesn't move above that. I choose my way where traffic doesn't exist.

I hope your engine could get away with it.

Greetings,
Thomas

 

[JoeSchmoe]

You might want to inspect your coolant bottle for hairline cracks. As others have pointed out, they crack when they get old. Look for green colored slime or dried residue left by any coolant that may have leaked out. If you dont find anything, you can try refilling it, drive around a bit, and then re-inspecting it. The added pressure might force some to seep through the crack or you might be able to hear some hissing.

-- Joe

 

[zanardi 47]

Hi Richard

My car is kind of overserviced, the coolant was changed this year. So I'm not sure if they had filled it completly up as it is quite different to avoid air in the NSX system.

The other question is: Shouldn't be the coolant system a closed system? I mean if something is missing then there MUST be a leak?

Greetings,
Thomas

Yes, the engine cooling system is a closed system (i.e. degas vs overflow system - as sometimes referred in the automotive industry). Therefore, that would mean coolant is escaping. The root cause on the change in coolant levels over time could be due to many variables (i.e. leaks at various locations within the cooling system).

The severity of the leak is something that needs to be quantified. That would help understand how much you are leaking and understand where one could start looking. It could be as easy as a hose joint or radiator tank/gasket/header leakage.
Or as hard as a engine block leakage into the engine oil and blown out your exhaust ... etc. etc.

As for the car being overserviced … my opinion is if the hoses/clamps have not been changed for a 1991 car … I believe it would be good idea to change them at your next coolant flush. Not due to miles, but due to time. (similar view on timing belt ... most NSX users probably change belt due to time not milage). It all depends on one's operating environment, etc. etc. ...

G'luck!

Richard

 

[zoomnsx]

When was the last time the cap was pressure checked?

 

[goldNSX]

When was the last time the cap was pressure checked?

I don't know if they ever checked the cap.
UPDATE: I've noticed some blue spots on the hoses below and on the expansion tank itself. I think that's it.
Thanks for the help.