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I have noticed that I keep adding coolant to my reservoir, but within a couple of weeks it is gone. I did some googling last night and this seems to be one of the symptoms of a blown head gasket. I looked around a little bit to see if I could see a leak anywhere. All I am seeing are the leaks below. In addition may oil pan gasket and rear differential cover gasket are both leaking, but don't think it is related. 

Can someone take a look at these pictures and see if they can identify where that could be coming from. The liquid appears to be oil as best as I can tell. I am colorblind so I am going off the consistency more than anything. 

This is a 1983 280ZX Base.

Thanks!

I can’t see anything in the pictures, so cannot comment on you particular situation.

Coolant can leak from the water pump shaft, when the seal gives up. That may be what you are seeing there.

As for the possible head gasket leak, pull the spark plugs. If coolant is leaking from a coolant passage to a cylinder at the head gasket, the plug for that cylinder will be clean. As coolant escapes into the combustion chamber, it scours the chamber clean, along with the plug.

Checking cylinder head bolts for tightness is part of routine maintenance on an L series engine. I check mine every time I adjust the valve clearances.

 

The pan gasket leak and gear lube leak at the differential are easily corrected. Simply drain, remove, clean, install new gasket and refill. I usually wait until the leaks are leaving puddles before addressing them.

 

Here are a few more pictures zoomed in further. What I am trying to point out is the sludge. It's in the water pump area but I would think if I was losing that much coolant there that it would show up on the ground at least a little. 

6 minutes ago, rogerwilcos said:

Here are a few more pictures zoomed in further. What I am trying to point out is the sludge. It's in the water pump area but I would think if I was losing that much coolant there that it would show up on the ground at least a little. 

That looks like dirt, collected on a minor bit of engine oil that has weeped out somewhere on the front of the engine. Unless there is a wet, runny stream of oil leaking out I wouldn’t get concerned about it.

You can spray some Simple Green on it and wash off fairly easily. A small stiff bristle brush will help to break up the dirt and grime.

1 hour ago, rogerwilcos said:

I have noticed that I keep adding coolant to my reservoir, but within a couple of weeks it is gone.

How much driving are you doing in a couple of weeks?  And how much is disappearing?  A whole tank's worth?

Does the exhaust smell like coolant?  OR do you smell coolant in the engine bay?

Check your spark plugs.  HG leaks tend to clean the cylinder that is getting the coolant.

Also, check the back of the cylinder head over the starter.  Mine had an external HG leak there.  The coolant ran down the back of the engine while it was warming up.  Once the engine got hot the leak sealed up.  But you could see the stain it left.

Ok, to be fair my estimate isn't exactly correct on my drive time. I don't drive this thing much. In the two years I have owned it, I have maybe put 500 miles on it. I have probably filled the coolant reservoir 5 times. So maybe every 100 miles? It's very possible it is running out sooner and I am not noticing it. And when I fill it, the whole reservoir is dry. 

The exhaust does have an odor to it .... but I couldn't say it smells like coolant. I guess I am not used to the smell of coolant so I would need to double check that. There is no white smoke coming out the exhaust, that is for certain. 

I replaced the spark plugs not too long and none of them looked overly clean. 

I need to check because what I think was the oil pan gasket leaking is right back where the transmission is as well. I need to grab a picture there as well. 

My coolant bottle level never changed over years.

If the engine is consuming coolant, the level should drop each time the engine cools down.  Coolant from the overflow bottle only enters the radiator when the coolant system pulls it back in as cooling creates a vacuum in the system.  Often when you have an external HG leak the coolant doesn't get sucked in because the vacuum is broken by the leak.

Mark the bottle with a Sharpie and see how fast and when it disappears.

Ok I will give that a go and let you know the result. 

Coolant leaks can be pain to track down sometimes, especially if they are small because the hot motor will dry them up and then may not leak once the pressure drops.

Look for signs of dried coolant (whiteish crust/corrosion or may be tinted the color of your coolant) around any water connection and fitting, and along any hose and pipe. Thermostat housing and its connection to the head. You should also have a line that runs from the T housing to heat an air control valve that’s on top of the intake manifold and back across the front of the motor. Hoses on the passenger side that go to the bypass and to the heater core. Heater core/ floor damp/ coolant smell inside. And possibly finally, check for signs of wet or dry coolant all over the radiator. Mine had tiny leak in the core and on top end where the support piece attaches.


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So far all I have noticed is a bunch of sludge around the water pump. It looks black though....like dirt. 

Check your weep hole.

 

You don't have to get personal with me! O wait....

LOL.

My Barracuda was in the shop, so I was in a rented Stingray. And it was overheating. So I pulled into a Shell station.....