On my s2000 I just noticed that my coolant reservoir is full and not draining back into the radiator. What can be causing this? Also after acceleration on decel my friend who was behind me noticed a little white smoke. I'm also on e85 not sure if that has anything to do with that. I don't appear to be using any coolant and my engine temps are fine.

 

can our cars run on e85?

cars don't "use coolant". its not a consumable like fuel. the reservoir should remain at the full line or between the low and high line all day long.
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e85? someone chime in on this one- I wouldn't put in e85 personally.

darcy

 

The overflow tank only drains into the radiator when the coolant level is low in the rad and engine is low and the system sucks out of the overflow tank. When coolant temps are hot the system dumps into the overflow tank, after cool down the engine and rad suck fluid back out of the coolant tank.

Check to see that the hose in the overflow tank has not fallen off and reaches down close to the bottom of the tank. When the car is totally cool open the rad cap and makes sure the fluid level is full to the base of the rad neck. If both things check out then you are safe.

 

My bet is that it's a worn radiator cap. Buy a new one and see if that helps. The cap is what allows the coolant back into the system from the over flow.

 

I did try new cap. Doesn't change. Might be headgasket?

 

Avoid E85 for other reasons: degradation of rubber seals.

 

what is the problem here? your coolant is at full, that's a good place for it to be.