The smell of automotive grease fills a college hallway and clanging noises emerge from the workshop where Saudi Arabian men gather around an engine.
These are not high school graduates, but older students in a pioneering programme for extending skills throughout society.
The kingdom for the first time is giving short technical courses - among them household electronics and computing - to men and women who say it's a further step towards easing their country's reliance on foreign labour.
The move complements efforts to build a more self-reliant economy after the collapse of global oil prices.
It also helps dispel misconceptions that Saudis don't like to get their hands dirty in manual work, much of which is done by millions of expatriates.
"In my home I can fix it," said Mohammed al-Harbi, 29, who works in his family's small business and joined the household electronics course at Riyadh Technical College.
"I don't want to hire someone."
The world's biggest oil exporter last year embarked on a wide-ranging social and economic reform plan to wean the economy off oil by broadening its industrial, investment and small business base to employ more Saudis.
It calls for improved education and expanded vocational training.
The new adult courses are not designed to qualify people for the job market, said Ahmad Fahad al-Fahaid, who heads the Technical and Vocational Training Corporation (TVTC), the government agency in charge of skills development.
They should, however, help them develop just enough knowledge to avoid having to call in expatriate labourers who "offer some maintenance or skills that can be done by Saudis," Fahaid said during a visit to the automotive workshop.
"Nobody told them, nobody taught them, nobody trained them, so that's why we stepped in" to offer skills that will help Saudis do the repairs themselves or, at least, to better oversee those doing the work, Fahaid said.
Classes are free except for a small registration charge.
Official figures show close to nine million foreigners are employed in the kingdom, which has a local population of more than 21 million.
That was before an intensified effort to reduce the kingdom's reliance on foreigners as oil prices settled at around half the level they were three years ago.
A weaker economy forced Saudi Arabia to delay major infrastructure projects, temporarily halt public service benefits, and prepare to implement taxes for the first time.
Coinciding with the pilot training programme, Saudi Arabia gave illegal foreigners three months to leave without penalty.
More than 345,000 have already stepped forward for the amnesty which ends later this month, the Arab News reported in early June.
Fahaid said that if Saudis can do basic repairs themselves then expatriates who remain should have "the skills needed to give an added value" to the economy, rather than performing menial tasks.
Students welcomed the chance to pick up new skills, and said they want more.
"We have learned about vehicles and how to maintain them. We learned a lot already," said Ali al-Qasim, 26.
I 'can do it'
He was one of several men dressed in brown smocks watching the oil drain from the engine of an old sedan hoisted above them.
Across campus, a student reassembled the power unit of a dismantled air conditioner as about 15 classmates followed his progress.
Sultan Abdullah, in his late 20s, said the four evening classes weren't enough, especially for someone like him. Educated in Japan, he lost his job with a government ministry earlier this year.
"Young people, they have no work," Abdullah said, pointing out two other unemployed men in his class that focused on cooling systems.
Saudi youths face "strong competition" from South Asians and other expatriates, and "it is better for our country" if more locals could find jobs, he said.
But the night school is designed to fill a gap, not for job training which is covered in many other TVTC programmes, Fahaid said.
A foreign education expert in Saudi Arabia earlier told AFP that education and training reforms will take years. The kingdom's well-equipped colleges may "talk the talk" but standards still lag, the expert said.
While training in certain trades already meets global standards, Fahaid conceded that "in some other areas we need a lot... to develop our capability, and that's what we are doing in TVTC."
The pilot project for more than 4,600 trainees ended before Ramadan. It is due to continue, with expanded course offerings, after the Muslim fasting month finishes in late June.
For women, the programme offered basic computer technology, hairdressing and beauty instruction.
It reflects public "requests for different kinds of courses" for all ages, Fahaid said, adding: "A lot of Saudis are keen to learn new skills."
Among them is Suliman al-Kuoboor, 52, a Royal Saudi Air Force flight engineer.
"I came here to make more knowledge for myself," he said.
Instead of calling a foreign technician, "you can do it by yourself," he said, expressing confidence in his new skills for connecting household wires, switches and lights.