NASCAR Chairman Brian France expressed optimism Tuesday that Monster Energy will remain as series sponsor after this season and said that the Cup Series could use one more manufacturer.

France made his comments on “SiriusXM Speedway” on SiriusXM NASCAR Radio.

Monster Energy, which completed its first year as series sponsor in 2017, was to have informed NASCAR by Dec. 31 if it would remain beyond the 2018 season. NASCAR President Brent Dewar said last month that the sanctioning body agreed to extend that deadline.

“They have had a really good run with us, and we’ve had a good run with them, and my hope and feeling is that that’s going to continue,’’ France said Tuesday. “They’ve been good partners. They’re bringing a lot to the sport. They’ve got a lot on their plate and so do we. We’re working with them to make sure that we have as long an agreement as we can. I think we will. I think it’s working that good for everybody. I’m real pleased with it.’’

Asked by “SiriusXM Speedway” host Dave Moody if there is a deadline on when Monster Energy must inform NASCAR of its decision, France said:

“There’s always that, but we just look at our partners differently. We work though everything. Everything to us is long term, whatever that means in a given relationship. My sense is that it has really worked for everybody. It’s also new. They’ve only been here, my goodness, just completed the first year. They’re working out some things and that’s understandable. It’s all good, actually really good with those guys. Love those guys.’’

Last month, Rodney Sacks, chairman and chief executive officer of Monster Beverage Corp., said during an investor meeting that the company was “evaluating” its future with NASCAR.

Sacks was asked in that meeting about the return on its investments, including NASCAR.

“I think that we have been quite successful,’’ Sacks said. “I think we have got a lot more visibility, a lot more recognition for the brand through the NASCAR sponsorship. It’s very extensive. It’s on TV. It’s appearing on the talk shows. We look at the metrics that the NASCAR folks give us and it certainly does seem to have been enhanced. Now to what degree, that we don’t know.

“Certainly we do believe we have been able to increase penetration but again it takes some time. I think we really started in NASCAR at the beginning of the year — very, very quick decision to go into NASCAR (and) it took us a little bit of time to get up to speed and get our activation going. We think we’ll see lot clearer benefits and more benefits coming from that relationship this year.’’

As for manufacturers, France said he felt there was room for one more in the Cup Series to join Chevrolet, Ford and Toyota.

“There’s a lot of work going on on that. Clearly we believe that the sport could not only absorb but welcome another manufacturer. These are tricky things to do. They’re very difficult to pull off. We’re just going to work toward that goal. I believe over time we’re the best opportunity not only in North America, maybe the world in terms of motorsports. We’re going to be aggressive in talking to other manufacturers as we go down the road.’’

Why just one more manufacturer?

“I think there is a limit,’’ France told SiriusXM NASCAR Radio. “There’s only so many key teams that a manufacturer can get their hands on and that takes time,’’ he said. “They want to have good performance and the right team alignments. Most importantly, they want to align themselves to the right teams and sometimes the teams aren’t available to do that.

“Using the Toyota approach that they had, that took them a long time to be competitive. I think the next manufacturer would probably like to shorten that timeline a little bit and be more competitive quicker. We will get another manufacturer, but it’s one step at a time.’’

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