Well, sitting in stop-and-go traffic for an hour in 100 degree temps didn't seem to help my cooling system any. I never went over three bars (AP1) but some coolant seems to have spattered out of the radiator from the area in red. All previous days' driving in 100deg heat wasn't an issue, when I was able to stay at 60 to 70 mph.



I've never flushed the coolant system, and over the years (11 of them, and 105k miles) I've added distilled water at times to keep things topped up. (Freezing isn't much of a concern here.) So I suspect I'm running a good bit more water than antifreeze - I suspect my boiling point has dropped a good bit. The good news is the engine is staying in an acceptable temp range, but I'm worried about my radiator now. I have no idea how it's constructed in that area - is it likely to be broken and in need of replacement? (Majestic's price is $270.) Or do I need just do a flush and refill of proper 50/50 coolant/water?

 

Are you sure its not blowing out from the expansion tank and getting on the rad?

As you add water, your corrosion protection goes down.

If you do get a new rad, use STRAIGHT Honda TYPE2 blue coolant, and never have corrosion issue...ever. You'll need 2 gallons.

The core is alum, and it is crimped top and bottom to plastic tanks.

do you have a vented hood? Vented hoods aloow uv light to hit the radiator, turning it white and splitting it open. I have replace 2 radatiors due to a vented hood.

 

If you're ordering from Majestic, the part number for the coolant is OL999-9001.

 

Billman, definitely not an issue with expansion tank.
Hmm, sounds like a busticated radiator (doesn't matter whether from corrosion - hope not for the engine's sake - or from water boiling up and producing too much pressure.) Dangit.

 

I'm pretty sure that demineralized or distilled water only have about a half life of de-ionized water.
The factory fill when the car is new is good for 5-6 years or 100k (?), so therfore your changes should be 2.5-3yr or 50 thousand miles if your using distilled water . I think there is a good chance you may have to fix/replace the radiator.

 

What the heck does this even mean????
Oh, and demineralized and de-ionized water is the same thing.
BTW, a year 2000 S2000 has a different cooling system maintenance schedule than all other years of S2000.

 

Well, you may be right. De-ionized may be a further refinement of demineralized since distilled would also be partialy or mostly demineralized. I think I would still look for the words "de-ionized" on the label.

 

[quote name='JackS' timestamp='1309309484' post='20729373']
... since distilled would also be partialy or mostly demineralized....

???????????????????????????????

 

This is getting too painful to witness.
Distilled water is the result of collecting the condensate of boiled water. The other two are used interchangeably and is the result of running water through chemical cartridges, how many cartridges will determine the final purity of the water.
In the case of water for engine cooling systems, it doesn't matter which of these you use so long as you don't use it out of your tap.
Besides, this is somewhat irrelevant for the OP's situation as that is more to do maintenance neglect and the continuous adding of water without an equal amount of anti-freeze.

 

So ultimately, regardless of the cause (and what the water I put in can be called ) - if the pressure got high enough for coolant to force its way out of the radiator like I've indicated - is the radiator pretty much kaput? Or is this possibly a designed pressure relief system, and I just need new coolant?