Uh oh - missing coolant

Damn, the Sentra is down on coolant suddenly. Its not in the oil, but its not on the garage floor either. I'm afraid the turbo has taken its toll on the head gasket.

Leak down test.

Or pull the plugs an pressurize the coolant wait over night and then spin it over and see if you win a prize.

Jerk the plugs and look for one steam cleaned? Apply never seize liberally on re installation?

Make sure it's not leaking somewhere before assuming it's the head gasket.

I have owned 5 modern FWD Nissan, and my current B15 is the only one that hasn't leaked coolant from somewhere.

My first B15 leaked from the top rad hose, but it never left a puddle. I'm guessing the soft engine mounts pulled on the hose enough to make it leak under load.

I have found that you never notice a slow leak... until it appears to be a large leak

Rent a cooling system pressure tester. The one Advance has is pretty nice. The Autozone one isn't.

If it's not in the oil, ATF (if automatic trans), or steam cleaning one or more cylinder, it's some external leak that may or may not be a head gasket.

Kenny_McCormic wrote: If it's not in the oil, ATF (if automatic trans)...

An automatic Spec V? That would be a good trick.

I went to check the spark plugs this afternoon, and when I took off the first coil pack, half of it stayed behind on the spark plug. Since I have to drive it to work tomorrow, I put it back together until I can source a replacement and figure out the proper way to remove it.

I filled the radiator back up; it took about a third of a gallon to fill it and the overflow reservoir. I'll keep an eye on the level over the course of the week.

Aslo check the radiator cap, if it won't hold pressure, it will push out coolant.

Kenny_McCormic wrote: Aslo check the radiator cap, if it won't hold pressure, it will push out coolant.

Well, the overflow reservoir was empty also, so that's most likely not the issue.

I drove it to work this morning (ran great!) and checked the level when I got here. Still right at the max line where I left it yesterday. So far, so good.

And still good; no discernable coolant loss. The radiator fan was replaced by an AC shop recently; its possible they took off the upper radiator hose and forgot to top it off.

It might simply have had some air trapped in it that burped out when you drove it and topped it up.

So here we are at the end of the week, and the coolant is down a little bit (about an inch) in the overflow tank. It's right at the top of the radiator filler neck, so if I am losing coolant, its not very much. Still no sign of leaks or white smoke in the exhaust. I'll just continue to monitor it for now.

Take a sharpie and put a dot on the overflow jug to mark the current cold level.

And the final chapter in the saga - the plastic end cap on the radiator succumbed to age and turbo heat. New radiator is in place and the Silver Bullet is ready for this weekend's autocross.

That is great!!!