Weird little coolant leaks.
 

Hello fellow Z family. In the process of pulling my spark plugs to verify they were not fouled out (different issue entirely) I noticed dried coolant on the smaller coolant lines on the throttle bodies as well as the small line leading to the overflow unit that coolant has been seeping out of these lines even though they are over the barbs and have the clamps in place as well. I pulled the radiator cap to see if there is any coolant in the filler neck and noticed that it appears coolant is leaking from the cap as well. I have posted some pics.

I was wondering if anyone else has seen this. Seems like maybe there is too much pressure in the cooling system which is causing this to happen. Is that possible? I don't know if I have lost much coolant, the coolant temp on the gauge has always read well, never has been hot. I remember only once, on a very hot day, that some coolant blew out the overflow reservoir and made a spotted mess when the blue antifreeze dried; I cleaned that up but now I see more right below where the radiator cap is located so I am thinking that cap is leaking for sure (will be buying a new one). Looking for any thoughts on this.

I am FI with the stock Stillen setup.

I have the SC A to A setup and I also get some tiny bits of dried coolant on a connection or two. It has never increased and doesn't affect the coolant reservoir level so I don't really worry about it.

Use constant torque hose clamps; not a regular worm clamp like pictured.
Either the ones you squeeze or the ones that have a spring & torque to a certain inch# value...they will expand and contract with temperature changes, especially on silicone hoses.
:tup:

JC: The only one that has the worm drive clamp is that one shown in the picture which leads to the overflow bottle; the others have the stock constant torque clamps. The guys who installed the Stillen system put that worm drive one. I think I will replace all those little clamps with new ones since I have it apart.

Opt: Good to hear I am not the only one to see this, I feel better now. My reservoir still has a level between min and max so I don't believe I lost much. However, I do not see any antifreeze in the neck with the radiator cap off. Is that normal as long as I have water in the reservoir? I know with my truck I alway check level within the radiator.

All that looks fairly normal to me - it's hard not to get antifreeze spills or tiny leaks when assembling parts. Tiny leaks will usually self-seal after a while (depending on your definition of tiny). You should be able to clean the crud off with hot water. If you're real finicky, take some brass or stainless wool and polish the mating surfaces before re-assembling.

I have to agree. The oem spring clamps should probably clear that up.

Well, as I mentioned earlier (I think), the worm drive clamp in the picture was the only one on the car installed on the overflow line by the garage that installed the Stillen kit. The leaking shown in the picture on the throttle bodies still had the factory clamp. I have since purchased some new constant pressure clamps and installed them at the overflow and place a new one, slightly undersized, onto the water line for the TB that was leaking and will monitor it.

My Z has been sitting about one week without being started and I noticed that when I removed the radiator cap I could tell the cooling system built up some pressure even though the car was not started. This was even after I had already removed the cap and took the picture. Kind of strange how that system could create some pressure all on its own without the antifreeze getting warm from the engine.

I will have to say, so far, this 370z is one of the oddest cars I have owned. I thought Honda did some weird, ***-backwards, non-standard things but this Z is running a close second.

I will have to say this forum has been a wealth of information though, everyone is awesome.

Pressure test the cooling system, may be a head gasket leaking combustion chamber pressure into the cooling system. :tiphat:

Had a motorcycle that leaked at all of the hose joints. The oem spring clamps wouldn't hold pressure. Had to replace all the spring clamps with worm clamps.