A sheared bolt prevented Nico Hulkenberg from making his Formula 1 race return at last weekend’s British Grand Prix.

Hulkenberg joined Racing Point in place of Sergio Perez, who was ruled out on the Thursday prior to the event after testing positive for COVID-19.

The last minute call up saw the German driver bank 13th on the grid but come Sunday failed to make the grid.

“It looks like a bolt sheared within the clutch housing and that bolt got caught and therefore wouldn’t allow the internal combustion engine to turn over,” admitted the Team Principal, Otmar Szafnauer.

“So where the bolt fell off, it got jammed, and we couldn’t turn the engine over.

“It’s a bit early to understand why, but it did shear off so it could be a material issue, it could be an over-torque issue, I don’t know.

“I’m sure all of those bolts are torqued to a certain specification, say the torque ratio isn’t set right and you over-torque it, it could shear it.

“It could be a material issue in manufacturing, but until you look into all of those things, was the bolt brittle for example, I don’t know.

“So we’ll have to understand the root cause and make sure we fix it.”

Hulkenberg looks set to remain with the team for the forthcoming 70th Anniversary Grand Prix at Silverstone this weekend as Perez continues to isolate.

An initial inconclusive test result for Perez was followed by a positive test, but the during the delay between then regulations in the United Kingdom saw quarantine periods extended from seven to 10 days.

“We will adhere to the guidance of National Health England so we will do what they say,” said Otmar Szafnauer.

“I’m not sure if it’s 10 or seven-day quarantine still today, there are conflicting reports, but we will get guidance from the right people at National Health England and follow it.

“Even if it’s only a seven-day quarantine, he still has to test negative by the COVID code of conduct that the FIA have out there, so we will endeavour to test him on Thursday, and if he’s positive then he can’t come into the paddock anyway.”

“By National Health England standards, that inconclusive test would have been a positive, so you can look at it and say it’s the National Health England standards and he was positive on Wednesday already, and on Wednesday you had to quarantine for seven days, and the 10 days that came in the following day may or may not be retroactive, that’s the bit I don’t know.

“So we’ll ask that question of National Health England and whatever they say, that’s what we’ll do, we’ll comply with whatever they deem is right in this situation, but the ambiguity comes in because it was just on that transition point.”

As a result, Hullkenberg is expected to remain in the car for the coming weekend as Perez, his physio, and a member of his management team all quarantine following a visit to Mexico.

The lack of track time because of last weekend’s sheared bolt will have a carry-over as Hulkenberg gets up to speed with the RP20.

“It would have been very useful for Nico to get a race in, unfortunately he didn’t,” Szafnauer said.

“He did a great job jumping in the deep end, starting from zero really, he didn’t do any winter testing, didn’t understand the car at all, it’s a different car than he drove before, a different powertrain.

“The team is similar to when he was here, but he still had a different engineer as his old engineer is on Lance’s car, but the rest of the guys he worked closely with, so he did a remarkable job.

“It was a steep learning curve, he did great to qualify where he did and it’s a shame he didn’t get to race.”

Practice for this weekend’s race begins at 20:00 AEST on Friday.