Since CEO Elon Musk's Aug. 7 tweet saying that he was considering taking Tesla (TSLA -1.76%) private, the discussion around the company has focused on one big question: Will Tesla be able to find the funding it needs to go private at $420 per share? 

But there's another important question that was being asked before Musk's tweet changed the subject: How close is Tesla to running out of cash?

We got an answer -- sort of -- when Tesla reported its second-quarter earnings on Aug. 1. While Tesla's loss exceeded Wall Street's expectations, investors were mostly impressed by the electric carmaker's headline numbers, including its cash burn: Tesla's net cash outflow was just $130 million in the quarter. 

Has Tesla really turned the cash-flow tide? Not quite. Let's take a closer look. 

The entrance to a Tesla store in Walnut Creek, California.

Image source: Tesla, Inc.

Tesla's second-quarter result looked good -- at first

Tesla said that it had $2.24 billion in cash on hand at the end of the second quarter. That was down from $2.67 billion at the end of the first quarter, but it wasn't down nearly as much as some (including your humble Fool) expected.

In fact, Tesla said that its net cash outflow for operating activities in the second quarter was just $130 million, which is a big improvement over the $398 million net operating cash outflow it reported in the first quarter of 2018. That sure looks like a move in the right direction, and Musk expects more progress in that direction as the year goes on.

"We're highly confident of being cash flow positive and GAAP profitable in Q3 and Q4," Musk said during the company's earnings call.

But how did Tesla manage to spend just $130 million in cash on operating activities, which include things like manufacturing? Or to put it more broadly, how did it still have $2.2 billion in cash at the end of the second quarter?

A deeper dive shows that there are still concerns

It looks like the answer has a couple of parts. First, Tesla appears to have put off paying some bills. Second, Tesla drew heavily on its asset-backed line of credit during the quarter.  

About those bills: Tesla had a whopping $3.03 billion in accounts payable at the end of the second quarter. That was up 16.4% -- $427 million -- from the end of the first quarter. On top of that, it had an additional $1.8 billion in accrued liabilities (think of these as accounts payable that haven't yet been billed).

That's $4.85 billion in bills that were either due or coming due soon as of June 30. That's up from about $4.1 billion at the beginning of 2018, which is a sign that Tesla may have slowed the rate at which it pays bills.

There's more. Tesla has an asset-backed line of credit that totals a little over $1.8 billion. As of the end of the second quarter, it had used just under $1.6 billion of that, up from $1.28 billion at the end of the first quarter. Translation: Tesla drew about $312 million from its line of credit during the second quarter, and it had only about $231 million remaining on its line as of June 30. 

Between the payment slowdown and the line of credit, Tesla avoided burning about $740 million in cash during the second quarter.

Tesla said this week that things are improving

Tesla's cash balance has fallen even further since the end of the second quarter. The Wall Street Journal reported on Monday that Tesla's cash had fallen to $1.69 billion as of Aug. 12 because it made a $500 million payment on its credit line in July.

I suspect that payment was made to appease the lenders, as Tesla officials told the Journal that the company plans to reborrow that $500 million later in the third quarter.

Tesla also said that it expects its deliveries to increase in the second half of the third quarter. Between the cash flow from those deliveries, and the reborrowed $500 million, Tesla expects to end the third quarter with a cash balance higher than the $2.24 billion it had at the end of the second quarter, according to the Journal.

The upshot: Tesla will probably need a lot more cash, soon

Tesla knows that it's in a cash crunch. The company has recently taken significant steps to maximize its remaining cash, including laying off 9% of its workforce in June and reportedly asking suppliers in July to refund a portion of its payments since 2016.

That crunch stands a good chance of getting much more severe soon. Tesla has two big convertible debt issues coming due: A $920 million issue due next February, and a  $1.38 billion issue due in early 2021. Both will convert to stock if Tesla's share price gets above $360 and stays there for a while, but unless Musk's ambition to take Tesla private at $420 per share works out, that looks unlikely -- at least for that first payment due next February.

As of right now, it doesn't appear that Tesla has taken any steps to raise money via an offering of stock or bonds. It's possible -- maybe even likely -- that Tesla is trying to build a cash infusion into its go-private deal. But until (and unless) a go-private deal happens, Tesla's cash will continue to be a key concern for investors.