My 350Z has only 41,000 miles and I just noticed yesterday some white milky specs / spots floating on the surface of the coolant expansion tank. I also opened up the radiator cap, to find the same deposits. I then scooped out a little bit of the white stuff, and wiped it on a rag, only to see it was really light brown in color. The expansion tank also has a brown film inside of it on its walls.

I know that this sounds like a bad head gasket, but I refuse to believe it is true. The car's only five years old, 41k miles, and I sure as heck don't beat on it.

I suspect the culprit to be the Redline Water Wetter I added after my last coolant change about 10k miles ago (using Nissan OE coolant). I read someone having a similar problem with brown gunk forming in his cooling system online, so even though I take many things I hear online with a grain of salt, for my sanity I am running with the possibility that the Water Wetter is what is causing this.

I plan to go back to the dealer to flush out the current coolant and replace it with new. I doubt that this will remove the white/brown deposits in the system. What can I, or rather the dealer, do to completely clean the inside of the cooling system? Please help.

_________________
2004 Super Black 350Z Base - 6MT

In my humble opinion, you should FIRST eliminate other (more serious) possibilities.

Pull your plugs and examine them for uniformity. See if you have any weird deposits (or oily film) in any single cylinder. Then run a compression check on the whole engine. Any serious differences in compression will deserve your entire attention to that area.

Headgaskets are not always predictable. I yell at my wife each time she blasts out of the driveway before warming the engine to operating temperature.

If the car is performing well, you don't have milky oil, there's no smoke out the back and you don't hear any weird sounds (like a ticking), you shouldn't be skeered of a li'l ol' compression check.

Heck ~ it's a good way to get personally friendly with your Z car.

Frank

*(Reviews of Water Wetter describe it as an additive, used to reduce the surface tension of whatever liquid it's added to. That has certain advantages in certain applications, but comments tend to support it as best used in a straight water cooling system [like racing engines, which don't make the racetrack slippery when a hose breaks]. Some comments have cautioned against using WW with antifreeze).

I just found this while Google searching: http://www.rx8club.com/showthread.php?p=3004815 ...pretty disturbing.

I hope that doing a complete cooling system flush will restore things back to normal, and I hope no damage has been done by the WW in the past 10k miles I've used it.

Pictures of what I found, for reference. Also, the same white deposits are in the reservoir, along with a brown film.

_________________
2004 Super Black 350Z Base - 6MT

" "

Evil stuff?

I feel you're pain! I have worked for Nissan (dealers) for almost 18 years. Since the 350z came out, (See...there is a "god"!) they have generally been bulletproof. (As typical with Nissan aluminum V6 engines.) 2003 models had major alignment issues that tore up the front tires. (ROAR!!!) A handful of them had to have engines replaced because of oil consumption. (the "Anniversary" models come to mind.) Even those ran fine. I have seen the issue described (and pictured), and it was indeed caused by coolant additive. We used to goose up the parts on Major services with some stuff called BG Super-cool, which never caused any problems, but Nissan strongly discourages any kind of additives in any fluids. Partly because of issues like yours; which appears to a reaction of aluminum components to some(several) chemical components in some of the "aftermarket" additives. The cars we have "treated" for this condition required numerous coolant "flushes" (straight 50/50 coolant) and one car had to have a new water pump.(Impeller seal eaten away.) The only head gasket we have ever done was on a G35 that was severely and repeatedly overheated. Even then; double headgaskets, machined heads, all new fluids; car was good as new. (145k on car.) So take heart; things are probably not as bad as they look. RDM

Do you drive like an old lady and only go short distances? If so, that is most likely your issue, not a problem, engine condensation.

i've seen something similar to this..
on my GM V6 i found oily deposits inside my radiator and on the cap...
i talked to the dealer/ mchanics, and they said:::::
They put some special tablets in the coolant to help lubricate the water pump.
????? sounds dodgy but makes sense.....
i havnt paid any attention to it since and that was 2 years ago... no problems...,..

usually a head gasket failure will create bubbles at the top of the radiator..
but only if the failure is combustion chamber to water jacket...

if water is getting in the oil then it wont take long for the oil to turn milky and you'll also be lossing water and gaining oil on your dipstick...

If it is a Blown Head Gasket.

I can fix it! and it won't cost thousands,

Hate to think that, but having it checked will rest the mind. There's the gas sniffer method via the radiator fill neck, or a leakage test to look for bubbles.