Is it normal for the coolant reservoir cap to leak? I bought a new coolant reservoir and still leaks. Or could something else be causing this? There's no contamination in the coolant in there or anything, I just get an annoying coolant smell.

 

Did the new reservoir come with a new cap? That really weird. My car has overflowed but only come out the overflow tube, never out of the cap.

 

It's a new cap.

 

might wanna test that coolant for combustion residue. Im thinking you might be blowing bubbles up in that thing.

 

The coolant should come out the overflow tube, not the cap though. On first session at a track day, my car fills the reservoir and over flows it a bit because the coolant grows so much with heat soak. Doesn't leak from the cap though.

 

thats kinda why i was thinking bubbles, only way i could see coolant kinda spraying / pressure spiking inside the overflow.


Edit: by contamination do you mean you already checked for combustion residue?

 

How would I go about doing this?

 

they sell little tester kits at most auto parts stores, or just Amazon.

 

Valid point.




You're looking for a block tester. this

and you'll also need the fluid, which is on that page, available to buy as a package.

 

Purchased, I'll post results probably on friday whenever I get it. Thanks

 

They don't work.



Just check for bubbles coming out when you blip the throttle.

 

Make sure the cap is fully seated and the rubber gasket is still intact and not pinched. I know myself personally there have been times where mine didnt seat properly, really just user error on my part. Now out of habit when I put back on the cap I sorta twist it side to side to make sure its fully seated. Seems silly but might be as simple as that. Or perhaps the gasket is gone?

I wouldnt start thinking the worst already; might be something totally stupid like that.

 

Black light with dye photograph - interesting.

 

Did the combustion leak test, and results are clean. So I'm guessing just the seal on the coolant cap is bad then?

 

To answer your original question, no, its not normal for the cap to leak. On a cold engine, with the reservoir level topped off to the full mark, in normal driving the coolant level never climbs to the level of the cap.