Another coolant leak!

[Johnny-T]

So after getting my coolant leaks up front taken care of everything has been good for a month or so. But the other morning when I left for work I had a pretty decent sized puddle under the rear of the car right next to the passenger side tire. There has been no drips in that spot at all until now. When I had the car up on a lift, I had taken pictures of all the minor leaky spots but I didn't see anything in this area. I checked my coolant level and it wasn't low at all and nothing is leaking from the tank. My main question is where is this leak most likely at? I couldn't even see any coolant hoses above there so I'm not sure where to focus my search. I can see that coolant is dripping down onto the rear shock so it has to be above there somewhere. Any ideas?

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[sdg3205]

Looks like overflow from the tank to me

[Johnny-T]

Looks like overflow from the tank to me

That's what I originally thought as well, but its too far forward to be the overflow. Plus it continues to leak throughout the night even after the car is cool. My best guess is there must be a loose hose clamp somewhere lower and a little bit forward of the coolant tank. I cant see any wetness when I look down into the engine compartment but there is definitely something coming down onto the right rear shock.

[sdg3205]

When the tank blows out excess it usually travels forward on the frame. Feel the hose - is it wet?

[Johnny-T]

When the tank blows out excess it usually travels forward on the frame. Feel the hose - is it wet?

My overflow hose is a bit wet on the end but it's also usually pointed straight down to an open area above the exhaust. I don't see how it could be causing the puddle further forward next to the wheel.

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Last picture shows the spot where it has dripped just since I got to work a little while ago.

[sdg3205]

Time for a pressure tester. That'll show your leak in a hurry. If you don't see a leak it's the over flow.

[Delta DeLorean]

I have the hose from the overflow tank hanging in a plastic botle, so if anything comes out I know about it and it does not mess up the frame. Plastic bottle is held in place with a zip tie.

[DMC-81]

I agree with the overflow as the likely culprit. Mine overflowed once with the OEM tank and hose. As Dave said it travelled forward on the frame and onto the air deflectors and dripped some for several days. What a mess. My SS tank came with a clear hose. I bought a longer one and zip tied it to point down at the bottom of the quarter panel. It's not noticeable from the outside... Like so:
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Good luck.

[Jonathan]

Might be time for a replacement header bottle cap (http://store.delorean.com/p-6297-header-bottle-cap.aspx). They are designed to hold back pressure until about 15 psi, and then relieve... out the overflow hose. If the cap is bad, it may be relieving at a lower pressure, or simply letting it weep out slowly but continuously, even when the car isn't on.

Confirm the level in the reservoir tank too. Typically should be filled to about halfway in that tank. If it is (was) filled right to the top, you aren't giving it any room to expand as it gets hot and it'll come out that hose all the same.

[David T]

It can also be the cap itself. Make sure it is the correct cap and then have it tested. If you still have the plastic header bottle replace it. Check the hoses going to the header bottle for leaks. When cold it should only be about 1/2 full to leave room for expansion. If you do pressure test the system that does not test the cap. So, assuming the system tests OK but leaks near the cap, you have to suspect the cap.

[Johnny-T]

I agree with the overflow as the likely culprit. Mine overflowed once with the OEM tank and hose. As Dave said it travelled forward on the frame and onto the air deflectors and dripped some for several days. What a mess. My SS tank came with a clear hose. I bought a longer one and zip tied it to point down at the bottom of the quarter panel. It's not noticeable from the outside... Like so:
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Good luck.

I really like this. Thanks for the share.


Might be time for a replacement header bottle cap (http://store.delorean.com/p-6297-header-bottle-cap.aspx). They are designed to hold back pressure until about 15 psi, and then relieve... out the overflow hose. If the cap is bad, it may be relieving at a lower pressure, or simply letting it weep out slowly but continuously, even when the car isn't on.

Confirm the level in the reservoir tank too. Typically should be filled to about halfway in that tank. If it is (was) filled right to the top, you aren't giving it any room to expand as it gets hot and it'll come out that hose all the same.

For some odd reason, my tank only likes to hold coolant right up to the hole in the back. Ive tried filling it more but every time it just returns to the same level. Toby at DMCNW told me not to worry about it too much as some cars just do that. He said as long as the level is where my car likes it, then its ok. Whats strange is through all of the leaks I had a couple months ago, I never saw my level go down. Ive added coolant several times thinking it was low but it always goes back to the same level and stays. I did add coolant the other day so there is some overflow to be expected. I just don't fully understand how the overflow hose can be pointed directly towards the ground just behind the rear fascia with nothing in its way, and be causing a puddle and wetness a good foot or so forward next to the tire and on the shock.


It can also be the cap itself. Make sure it is the correct cap and then have it tested. If you still have the plastic header bottle replace it. Check the hoses going to the header bottle for leaks. When cold it should only be about 1/2 full to leave room for expansion. If you do pressure test the system that does not test the cap. So, assuming the system tests OK but leaks near the cap, you have to suspect the cap.

I have the SS bottle and the cap seems to be good. No leaks or wetness can be seen when looking around or down behind the bottle. Plus if you line up where the puddles are forming on the ground, its still a bit forward of the header bottle itself. That's why I think its a hose a bit further down and forward of there and not the overflow. I just don't know what hoses, if any, are in that area.

[sdg3205]

You can't just make guesses and our opinions only go so far. You have to pressurize the system. Every delorean owner should own or have access to a pressure tester. I've have used it hundreds of times to either diagnose a problem or get ahead of any new issues. These cars have ridiculously long cooling systems with more hose clamps than you can shake a stick at.

Get or rent a pressure tester. It'll pay dividends. If you had one you'd know where your leak was by yesterday ;)

[Johnny-T]

You can't just make guesses and our opinions only go so far. You have to pressurize the system. Every delorean owner should own or have access to a pressure tester. I've have used it hundreds of times to either diagnose a problem or get ahead of any new issues. These cars have ridiculously long cooling systems with more hose clamps than you can shake a stick at.

Get or rent a pressure tester. It'll pay dividends. If you had one you'd know where your leak was by yesterday ;)

I will definitely look into getting one. I plan on doing a complete cooling system upgrade in a few months when I get my Stage II done so hopefully all new hoses and clamps will keep the leaks away for awhile.

[Jonathan]

I just don't fully understand how the overflow hose can be pointed directly towards the ground just behind the rear fascia with nothing in its way, and be causing a puddle and wetness a good foot or so forward next to the tire and on the shock.

I have the SS bottle and the cap seems to be good. No leaks or wetness can be seen when looking around or down behind the bottle. Plus if you line up where the puddles are forming on the ground, its still a bit forward of the header bottle itself. That's why I think its a hose a bit further down and forward of there and not the overflow. I just don't know what hoses, if any, are in that area.

It does sound like a hose more forward than the overflow line. Do you have an auto-bleeder hose? That's about where that one ties into the system. Perhaps you could take a photo of the forward side of your reservoir tank that would show the connections on or near that side?

One other thought with the overflow hose... you assume it is staying pointed directly towards the rear when/if it goes off. If there is nothing holding it down, the force of the 15 psi and 220 deg F coolant coming out could get it to fly around a little bit or spray off of other things while relieving. 15 psi is no where near as much as a fireman's hose, but that little rubber hose doesn't weigh near as much either. Is the hose zip-tied or otherwise secured in place at all?

[Johnny-T]

It does sound like a hose more forward than the overflow line. Do you have an auto-bleeder hose? That's about where that one ties into the system. Perhaps you could take a photo of the forward side of your reservoir tank that would show the connections on or near that side?

One other thought with the overflow hose... you assume it is staying pointed directly towards the rear when/if it goes off. If there is nothing holding it down, the force of the 15 psi and 220 deg F coolant coming out could get it to fly around a little bit or spray off of other things while relieving. 15 psi is no where near as much as a fireman's hose, but that little rubber hose doesn't weigh near as much either. Is the hose zip-tied or otherwise secured in place at all?

I don't have the auto bleeder. But I plan on having one installed on the bottle and radiator when I replace all the hoses and clamps. And my overflow is not tied down at the moment. I never thought about the possibility of it moving around when its relieving pressure. Its a very good possibility that it could be turning forward and spraying it on something.

I will also note that today is the first day since the leak began that there has been no coolant on my garage floor. I checked my header bottle again and it has returned to its usual level after putting in extra coolant a couple days ago. Through all of this I haven't had any issues with cooling and the car is still running like a champ. I will get the car up on a lift in the next couple days and see if I can find a loose clamp or anything.

[Jonathan]

I don't have the auto bleeder. But I plan on having one installed on the bottle and radiator when I replace all the hoses and clamps. And my overflow is not tied down at the moment. I never thought about the possibility of it moving around when its relieving pressure. Its a very good possibility that it could be turning forward and spraying it on something.

I will also note that today is the first day since the leak began that there has been no coolant on my garage floor. I checked my header bottle again and it has returned to its usual level after putting in extra coolant a couple days ago. Through all of this I haven't had any issues with cooling and the car is still running like a champ. I will get the car up on a lift in the next couple days and see if I can find a loose clamp or anything.

If your car is running well, cooling well and not leaking anymore coolant, sounds to me like now would be a good time to zip-tie in a little plastic water bottle for the end of that overflow hose. Then whether you see a little coolant in that bottle or you don't, you can move on from this issue to something else.