Where is my coolant going?

[Stingray1967]

Ok guys, '94 Z here with about 31,000 on it. Top end porting from Corey a long while ago, headers, gears, big brakes, Fluidyne radiator. FUN car.

I filled the white surge tank to about 1/3 of the way up, and after a few weeks of driving it is empty. It looks like there is only one line that goes to that tank, so I am mystified as to where the coolant is going. I'm hoping it isn't a head gasket.

How worried about this should I be? The car keeps it cool just fine on the road (as long as you're moving).

Also, the black surge tank metal cap is almost impossible to get off. Not sure what to do there.

Any advice is appreciated.

[secondchance]

You need to push down while turning counter clockwise to remove coolant tank cap. Coolant should be slightly above the copper line close to the top of the tank.
When cold, coolant overflow cap/ dip stick reading on the lowest notch is not abnormal.
Are you running silicone coolant hoses? If yes, periodic snugging of clamps is recommended. Otherwise, when hot and under pressure, coolant seepage can occur but you will never know it because it?s only a seepage and will evaporate before you can see it.
Lastly, if you have a head gasket leak you will see continuous white steam coming out of the tail pipes even after the motor being fully warmed.
I don?t think you have any issue.

[Stingray1967]

Thanks for the detail, I'll go check those things. I tried pushing down on the coolant cap and it was VERY difficult. I'll try again.

And no, I'm not running silicone hoses. I think most (if not all) of the hoses are the originals.

[secondchance]

Actually, my experience when my motor blew the head gasket is abnormally high coolant level in overflow tank because the exhaust would go into the block and blow coolant into the over flow tank.
Coolant tank would low because the coolant was replaced with exhaust.

[Stingray1967]

Coolant tank would low because the coolant was replaced with exhaust.

So, how does something like that happen? I'm struggling to see how the coolant and exhaust would be close together.

[DRM500RUBYZR-1]

With luck, perhaps the level was low and all worked as it should restoring it to full, emptying the tank.
If it is continues, then further search is required.
Until you get that cap off, you are a bit in the dark.

At the age of these cars, I would also suggest exploring around the heater core.
They are now at or beyond the age of failure.
Any fogging of the windshield or interior odor?
Carefully look around passenger side footwell for any trace of coolant.

Explore around the lower radiator hoses. A small leak there is almost undetectable, but will leave traces. Has you temperature been running a bit higher?
The first sign is losing pressure which results in higher temp s and more variance in the temp.

Lastly, get a quality pressure gauge and test the system once you have dealt with that cap.
Don't take it past 15psi to avoid overtaxing the heater core.
It should hold to 15.
If it does not, you indeed have a leak somewhere.
Good luck and keep us posted of progress.
:cheers:
Marty

[Stingray1967]

Got the cap off. The photo shows where the level is. I backed the car out and put it in the middle stall. So it ran for about a minute. The white overflow tank is basically empty. No white smoke from the exhaust.

[Stingray1967]

With luck, perhaps the level was low and all worked as it should restoring it to full, emptying the tank.
If it is continues, then further search is required.
Until you get that cap off, you are a bit in the dark.

At the age of these cars, I would also suggest exploring around the heater core.
They are now at or beyond the age of failure.
Any fogging of the windshield or interior odor?
Carefully look around passenger side footwell for any trace of coolant.

Explore around the lower radiator hoses. A small leak there is almost undetectable, but will leave traces. Has you temperature been running a bit higher?
The first sign is losing pressure which results in higher temp s and more variance in the temp.

Lastly, get a quality pressure gauge and test the system once you have dealt with that cap.
Don't take it past 15psi to avoid overtaxing the heater core.
It should hold to 15.
If it does not, you indeed have a leak somewhere.
Good luck and keep us posted of progress.
:cheers:
Marty

Marty, thanks for all the suggestions. My car has an aftermarket Fluidyne radiator in it. I drove it to work most days this week. Ambient temp was in the 50s-60s. Coolant temp runs usually around 192. Although climbing a long slow hill on the interstate out of the river valley saw 200.

I have had the car in the air lots of times (have a lift at home). Have seen no signs of leaks. I added a little bit of coolant to the upper black reservoir to make it just below the overflow pipe opening, and I added a little bit to the lower white tank. When I checked the white tank dip stick today, it did have a little moisture on the bottom, so it isn't totally empty. Maybe there isn't an issue here. I'm still baffled at how the coolant goes down AND up that single pipe to the lower white tank.

I pulled the passenger floor mat out and felt all around. Even up under the hard plastic dash lower trim. Totally dry. I also looked from the top side at the heater area and saw nothing. There is no fogging of the windshield and no odor in the car.

[XfireZ51]

Have u checked the oil? Coolant can bet into the combustion chamber being sucked into the #1 and #2 cylinders from the coolant passage in the cylinder head going into the injector housing. The separation between intake tract and coolant path is not very wide and over time the IH gasket may give way along coolant to enter intake. White smoke would show up when you ?get on it?.
Also, pull those plugs on the first couple of cylinders for each bank. Are they steam cleaned?

[Stingray1967]

Just swapped the spark plugs. The front of the engine is on the right.

[Stingray1967]

Have u checked the oil? Coolant can bet into the combustion chamber being sucked into the #1 and #2 cylinders from the coolant passage in the cylinder head going into the injector housing. The separation between intake tract and coolant path is not very wide and over time the IH gasket may give way along coolant to enter intake. White smoke would show up when you ?get on it?.
Also, pull those plugs on the first couple of cylinders for each bank. Are they steam cleaned?

I haven't noticed any white smoke when I get on it.

[XfireZ51]

Just swapped the spark plugs. The front of the engine is on the right.

Sorry but I?m not allowed to view the pic u posted.

[XfireZ51]

How about a closer less grainy look at 1&3?

[Stingray1967]

In the foreground, left edge is the driver's side, front of the engine. Hope that is what you are looking for.