I have a coolant leak and I am pretty sure it’s from the expansion tank cap.

Is there a little hole hole in the middle of the cap where coolant comes out?

I have filled the coolant a couple of times. No overheating.

Is it time to replace the cap?

The coolant is very dark colored, is this normal?

 

I assume R50 is pressurized like most cars. I would not worry about it as it is likely normal if you keep the cold coolant near the max level. My R53 will always have some overflow after driven on track. Change in altitude will affect when the mechanical pressure relief of the cap as is the coolant chemistry and concentration. I concentrated during high school physics and chemistry classes so I don't waste money buying new caps unless they are really bad.

 

The R50 tank actually isn't pressurized; it's a different design from the R53. That said, those pictures aren't of a first gen engine bay. R56 maybe?

Coolant change interval for first gen cars is every four years. I'm not sure about other model years.

 

I had the same problem with a metal tank.. I kept the coolant level at half when cold and had it leak out the cap twice before reducing the coolant level to just above the baffel or about just a tad above a quarter full. That was two years ago and no leaks since.

 

Thank you. That makes me feel better. It happened over about a 1000 miles of driving.

 

Thank you. I accidentally posted int he wrong section. It’s a NA R56. I will move it to the appropriate section.

 

Thank you. That makes me feel better lol