1. I'm low on coolant, but am not leaking. Does this mean that the injector orings need some attention?

2. How can I check the health of my injectors? Buzz test the only way?

 

Just how low is your coolant? and is the level dropping over time or can you mark it and it stay where its at?

Also if it was leaking coolant internally, it wouldn't be the inj orings, it would be inj cups as far as that goes.
But it can also leak into the cyl if the head gasket blows out, or it can leak into the oil and vice versa in the oil cooler. Or you could also have fuel in oil, oil in fuel, or fuel in coolant or oil in coolant if the inj cup is cracked, it just depends on where the crack is.


The buzz test pretty much just checks the electrical side of the inj. From the pcm, idm, harness and UVCH and inj soleniods.

Ideally if you wanted to spec out the inj, you could send them out to someone like swamps or cass, etc that can tear them down, spec the internals and put them on a flow bench.

How many miles are on the inj now?

 

I'll track the coolant. I havnt seen it go past where it is now. My guess is that the original coolant is in there..

There are 150,000 on the injectors.

 

Change you're coolant. It wasn't designed to last forever. Also be sure you don't have a tiny drip coming out of the weep hole of the water pump. Often times when it starts to leak it's small enough you never see a drop on the ground until the leak gets bad.

 

Its on my list..

Where is this hole?

 

It's at the bottom of the water pump shaft hub behind the water pump pulley. When the shaft seal in the WP starts going out the first sign will be coolant leaking from the weep hole.

In this pic you can see where the coolant leak starts behind the WP pulley and runs down the front of the WP, the front cover and then to the lip where the oil pan mates to the block. The coolant usually collects on the lip and then flows down onto the oil pan. I caught this leak very early.



WP weep hole.

 

Or your radiator is leaking like mine did. The coolant was always running low and I could smell it every now and then. It leaked when hot and evaporated before it could leave a mark.

Funny thing is that all the local auto parts stores DID NOT have the attachments needed to pressure test the radiator...

 

I agree with all the replies above. Chris's comments are the most likely. When my water pump finally went out (240k miles), I started to smell a slight antifreeze odor when I parked my truck after a decent drive. I looked around really well and didn't see anything. Eventually my water pump puked about 4 oz of coolant on the driveway directly under the crank pulley so I knew it had to be the weep hole. I reached up behind the pulley and could feel it was wet in there so I ordered a pump from Clay. Installation was a breeze. By far the easiest water pump change I've ever had to perform on any vehicle.

Another possible source for a leak is the o-ring on the adapter tube that connects to the lower radiator hose. Because of the fan, a leak at this spot will blow the liquid back towards the front cover so the source might not be super obvious at first. I'll attach a photo that might help.

Word of advice...
If you find out that you do need to replace your water pump, then I recommend you order an OEM from Clay, PartsGuyEd etc. The OEM pumps come with a nice o-ring type gasket that seals nice the first time. I have heard stories of problems with leaking gaskets/o-rings from chain store auto parts houses...
Also, make sure you purchase the type that has the separate extension tube as shown in the attached photo. The integrated type might seem ok at first but then later could become a problem if you have to service your oil cooler. Just an FYI....