Boxster Coolant Problem

[JonnyHelps]

Hi Everyone,

I have a 1999 Boxster that is not leaking any coolant, but it seems as though the coolant reservoir needs topping up quite often. The coolant is not leaking from anywhere either. Does anyone know what this problem can be? Should I have the coolant system flushed out? Could the coolant to water ratio be off? I only use Porsche Coolant. The car has 115000 KM (75000 Miles). I'm not sure when the coolant should be changed and how often, I just bought the car recently and everything was topped up.

Anyway, if anyone can relate or help, then please let me know, thank you so much for your time and effort.

Sincerely,

Jon

[klueless7571]

Hi Everyone,

I have a 1999 Boxster that is not leaking any coolant, but it seems as though the coolant reservoir needs topping up quite often. The coolant is not leaking from anywhere either. Does anyone know what this problem can be? Should I have the coolant system flushed out? Could the coolant to water ratio be off? I only use Porsche Coolant. The car has 115000 KM (75000 Miles). I'm not sure when the coolant should be changed and how often, I just bought the car recently and everything was topped up.

Anyway, if anyone can relate or help, then please let me know, thank you so much for your time and effort.

Sincerely,

Jon

Have you ripped out the carpet in the trunk and behind the seats to inspect for coolant residue?

Derek

[JimEE]

If you still have the original coolant reservoir cap, replace it with the upgraded cap (part # ends in 01 instead of 00). I also had a slow loss of fluid in my 2000 S until I did the replacement. With the old cap, I never saw any fluid anywhere, just a slow reduction in the fluid level.

It could be other things, too, but this is the simplest, and it's a known problem.

Another simple thing it could be is cross threading of the reservoir neck that the cap screws onto, preventing a secure fit.

Good luck,

Jim

[tXster]

I have a 1999 Boxster that is not leaking any coolant, but it seems as though the coolant reservoir needs topping up quite often. The coolant is not leaking from anywhere either.

Hey Jon, if you're topping off, it's leaking and either/or burning off (can you smell it?), leaking around the pressure relief, bad water pump, and/or leaking in the trunk under carpet, or other. You'd be amazed on how much the trunk can hold. Also, what are the last 2 numbers on your coolant cap? My guess is is 00, you should replace the cap with at least 01

[White987S]

JonnyHelps, FWI, you can also top-off with distilled water.

[juniinc]

If it isn't leaking, replace the cap

[Tool Pants]

As others have said, pull back the carpet and see if there are signs of a leaky tank.

[Charlestonboxster]

Yep.

I had the exact same problem with my 98 at 75k miles also.

Replaced the cap per first recommendation.

Didn't help.

I was SURE I didn't have a leak.

Pulled out the carpet and fiberboard trunk liner...sure enough....hehe a little puddle of orange...

I did the coolant tank replacement per Tool Pant's past threads on this subject, problem fixed.

Not a walk in the part replacement, not complicated but a pain and takes time (3-5 hours)

if you are not a hard core save $ DIY'er, might want to have it done, if you want to tackle it,

tool pants threads are the bomb!