Thread: Loosing coolant?

"Unheeded" or "unneeded"? :o
There's a big difference.

Even if it is the thermostat or rad cap, that still doesn't explain the dissapearing coolant.

Yeah you have a leak. What kind of rad do you have? If it is OE with the nylon ends that is my first guess. After they see a lot of steam they start to get fissures. My next guess is you might have a bad/half tightened clamp on a coolant hose or the end of a really old coolant hose.

You should check for leaks in easy to see places after you get the motor hot. You can see and smell the steam.

There might be a residue you can look for too while the motor is cold.

Most likely what you have is a minor headgasket leak. The coolant is leaking into a cylinder and burning off undetected. Keep in mind in a case like this the coolant is only making it into the combustion chamber and your oil won't really show any of the typical "milky" coloration that would be a result of a major headgasket issue. In fact if the headgasket is only damaged at the combustion chamber the oil might never show signs of contamination. As someone else has said check the plugs and look for the one that is cleaner than the rest.....that is the cylinder that has the leak.

On a side note I find it interesting that this happened after you changed the radiator cap to the Nismo unit. Correct me if I am wrong but this unit allows more pressure to build in the sytem to allow a higher boiling point of the coolant, correct? In fact I just looked it up and the stock is 12.6 lbs...the Nismo is 16.8 lbs, a significant difference. Think about it..the coolant system has to build to 16.8 lbs in order to bleed off into the overflow tank. The higher the pressure in the cooling system the easier it is for the coolant to push it's way past the headgasket. For this reason I never understood the use of the the "high performance" radiator cap to aid in cooling. There are better ways to provide additional cooling. It is possible that the changover to the Nismo cap aided in the demise of your headgasket that was probably not in the best of shape to begin with.

That is a good theory with the rad cap and head gasket leak.

if you find nothing wrong after you've used the tool you posted about, do the FLUORESCENT DYE LEAK TEST. it'll find the smallest of external leaks with the black light.

do a pressure test...

Is your motor a high port?

So it has come down to a minor head gasket leak or a very small hole in one of the hoses, but it would have to be one of the hoses on the back side of the motor. the radiator hoses as well as the turbo lines have no leaks at all.

When I'll do the dye test, that will help point me in the right direction.

and yeah, it's a highport.

Ok I would do a pressure test first. Then look for a water leak on the back coolant lines.

If it is a leak back there.... They are not that hard to replace if you take off the intake mani. Which really isn't that hard.. Just time consuming. Get the hoses from GregV and you won't have to worry again.

^^^

ok awsome. I'll do a pressure test as well.
Thanks guys!!