Got back from a drive and let my 03 (143k miles) MT sit for a little. Came back out an hour later and noticed a small pool of coolant from front drivers side. Lifted hood and found evidence that the coolant had come out of my radiator cap.

I had taken the car for a short drive aprox 15 mins. During the drive when stopped at a light noticed the oil pressure had seemingly dropped to about 15 PSI. I have learned after looking into it that this is a normal pressure to see at idle. I perceived it usually hovers higher at idle though i cannot confirm. Pressure returned to normal when at the proper RPM. I had also heard and felt a clunk when shifting between 2nd and 1st that only happened one time. Shifted normally after while driving home.

I wasnt not doing as good of a job monitoring my temps while this was happening so i cannot confirm if they were high or not, however when i discovered all this i turned the electronics on and the temps where at the correct level (one hour after this occurred). I turned the car on and let it idle for a few minutes and noticed no change in temperature.

Could this possibly be a faulty radiator cap? Is that even a thing? I do not have the most knowledge so i could be missing something, but i dont have any reason that i can think of to believe my car overheated. Please let me know if this could be the cultrate or if I am missing something. Thanks!

 

The cap can go bad, yes

 

I noticed more coolant had leaked when i went out this morning. Not a huge amount but enough to take notice. Im wondering if more fluid came out than I initially though, it all just took a while to be pulled out by gravity, it didnt evaporate over night, or i have a leak elsewhere as well. Will investigate more later this evening.

Possible my head gasket is damaged? Going to check how the coolant looks tonight and try and get a pressure test done. Let it idle for longer and see if i smell anything in the exhaust

Any ideas welcome

 

Before you get too worried, just try replacing the radiator cap. They can become defective within 4-5 years, and are a replaceable maintenance item. We should all recognize that these type of components do not last forever!

Replace, and report back afterwards.

 

You should be able to see where it's leaking from

 

Looked like it came out of the tube that sits just below the radiator cap. I believe that is the radiator overflow tube?

 

Correct, and it should be connected, unless it's cracked.

 

Sorry for the huge *** picture. Got a new radiator cap from Nissan. Looks prety much identical to old cap. I cant see any damage to old cap. The little metal tip(?) in the center of the cap is bent slightly where the new one is straight and stick out just a tiny bit further. Coolant looks fine and the level is good.

Im going to drive if for a bit tonight to see if the temps go up. Any other recommendations?

 

A lot more fluid is coming out now. Looks like it is coming from behind the radiator or under it. I cannot get fully underneath the vehicle, but if looking at the car from the front, all the coolant is seemingly coming out of the bottom right hand corner of the radiator. Maybe behind it but I cant get a good look

 

First, you can't tell if a radiator cap is defective internally. They just stop functioning over time. More importantly, it sounds (and looks) like the radiator itself may be damaged and will need to be repaired or replaced. With 143K on the clock, it's not unexpected. While you can look for a radiator shop in town that can pressure test, clean and repair your OEM radiator, there's always the option of replacing it with a new one. The OEM radiator has plastic end caps around a aluminum core and may not be rebuildable.

If nothing else, good on you for noticing the leak before it could damage your engine.

 

I am thinking it is radiator as well now actually. I could not feel any moisture on any of the hoses in that location however just underneath the back side of the radiator it was pretty wet. I am very glad I noticed this early as well, thanks. And it looks like replacement radiators are pretty cheap! I would still like to get a second opinion though.

Thanks for you help with this. I think we might have narrowed down the problem

 

Now is a good time to make sure your radiator fans both work. With the car idling, turn on the A/C, they should both turn on. The reason I mention this is the fans are a necessary part of the assembly, if you choose another manufacturer for the radiator you may need to buy their fan assembly or fab your old one so it fits.
GL!