It certainly makes things interesting for tomorrow. Can McLaren sort things out and get some decent running in on the final day of testing? Join me at 08:00 GMT tomorrow to find out.I'll leave you with Andrew Benson's report, and until tomorrow, good bye.
- Maldonado fastest on third day of testing
- Vettel in gravel on testing return
- Ferrari driver goes on to complete over 100 laps
- Lewis Hamilton enjoys trouble-free day
- Jenson Button misses most of afternoon
In total for testing McLaren have managed less than 200 laps. Every other team has managed well over 400, with Mercedes leading the way with over 800. Worrying times for McLaren?
1 Pastor Maldonado (Ven) Lotus-Mercedes 1:24.348
2 Max Verstappen (Ned) Toro Rosso-Renault 1:24.739
3 Lewis Hamilton (GB) Mercedes 1:26.142
4 Marcus Ericsson (Swe) Sauber-Ferrari 1:26.340
5 Sebastian Vettel (Ger) Ferrari 1:26.407
6 Daniil Kvyat (Rus) Red Bull-Renault 1:26.589
7 Felipe Massa (Brz) Williams-Mercedes 1:26.912
8 Pascal Wehrlein (Ger) Force India-Mercedes 1:27.333*
9 Valtteri Bottas (Fin) Williams-Mercedes 1:27.556
10 Jenson Button (GB) McLaren-Honda 1:29.151
Out comes the chequered flag to bring day three to a close. Five drivers got over 100 laps under their belt, a figure Jenson Button can only look on enviously at after a frustrating day for McLaren.
Pastor Maldonado finishes fastest for the day.
Jenson Button completes a lap, heads in, heads back out but soon heads back in again.
That's better, a 1:27.556 is almost two seconds quicker than Jenson Button's best effort, so Valtteri Bottas is up into ninth.
Ah, a late timed lap for Valterri Bottas but it is not enough to lift him off the bottom of the timesheet as he clocks 1:38.067.
Jenson Button heads out, he'd certainly welcome a few trouble-free laps, and he is quickly followed by Marcus Ericsson, Valtteri Bottas and then Pascal Wehrlein.
The green flag is waved and 10 minutes remain for teams to rattle up a few late laps.
It was the Toro Rosso that brought out the red flag and the recovery truck trundles over to lift Max Verstappen's car. Should be enough time to squeeze in a few more laps before day three of testing comes to an end.
Max Verstappen stopped just before Turn 1, while Jenson Button also came to a halt at the pit exit.
McLaren head back out, but there is a red flag...
A bit more activity on the circuit as we enter the final 30 minutes with Sebastian Vettel increasing his lap total for the day in the Ferrari. Pascal Wehrlein, in the Force India, and Toro Rosso's Max Verstappen are also out there.
Force India: Pascal's tally is up to 77 laps, a very good haul for the youngster who has been through a plan of setup work and longer runs. The crew has completed some routine checks after the latest long run, so we're ready to put in some extra laps before the end!
Daniil Kvyat pops out in the Red Bull but is straight back in and once again the circuit is empty. Sensing there is little more to see today, spectators are starting to make their way home.
Pastor Maldonado cuts a lonely figure as he weaves his way around the circuit in the Lotus - the only car on the circuit.
Just over 45 minutes remaining of testing for today, will we see another appearance by the McLaren? Yes, is the answer, as Jenson Button ventures out but how many more laps can he add to the 18 he has completed today?
1. Max Verstappen 125
2. Daniil Kvyat 102
3. Sebastian Vettel 101
4. Pastor Maldonado 94
5. Lewis Hamilton 86
6. Pascal Wehrlein 76
7. Felipe Massa 55
8. Marcus Ericsson 46
9. Valtteri Bottas 36
10. Jenson Button 18
Nothing much going on on the circuit at the moment, with Max Verstappen and Valtteri Bottas performing pit-stop practices. Sebastian Vettel continues to increase his mileage on the circuit as he surpasses 100 laps for the day in the Ferrari.
Marcus Ericsson, on the soft tyres, is up to fourth with 1:26.340, and the times from third fastest to seventh fastest are separated by nine tenths of a second.
Ericsson, Max Verstappen, and Pascal Wehrlein are the drivers on the track at the moment.
F1 journalist Dan Knutson in Barcelona: "Williams did the same thing last year - doing pit stop after pit stop with the driver coming in after each lap and therefore never setting a lap time. Valtteri Bottas has now done 34 laps doing just that. It's expected that he will do some proper timed runs before the session ends."
Brief. Jenson Button is once again back in the pits after lap 18.
A limited-power McLaren is guided back on to the circuit by Jenson Button.
Meanwhile, Daniil Kvyat has surpassed 100 laps for the day as he heads off on number 103. Only Max Verstappen, on 115, has managed more today.
Chief F1 writer
"More on McLaren's problems. It turns out our earlier suspicions were right - McLaren's delays have been caused by the same part that stopped Jenson Button on Thursday, a seal on the motor generator unit that recovers energy from the rear axle (the MGU-K). A new design was fitted to the car for today's running and Honda hoped that would fix the problem. But it has not.
"A spokeswoman said: 'After the morning session, the car fed back MGU-K issues similar to what we experienced on Thursday, so we brought it back to the garage. After a thorough check, we have decided to resume testing with limited power to the MGU-K. A new re-engineered seal is scheduled to arrive and will be applied later this evening.'"
It looks like it is a short stay back in the garage for Jenson Button, with the McLaren seemingly set to re-enter the fray. Meanwhile, Lewis Hamilton is back on the circuit, currently lapping in the 1:26s.
Valtteri Bottas is up to 30 laps without setting a time as Jenson Button heads back in at the end of lap 15.
Jenson Button completes his 14th lap of the day and stays out on the circuit. All being well, he will have 90 minutes out there to rack up the mileage.
...and out goes Jenson Button, his first trip on to the circuit since this morning.
Daniil Kvyat on his race simulation, pits for softs with 12 laps to go. Meanwhile, it seems like there may indeed be some activity in the McLaren garage...
Chief F1 writer
"McLaren say they hope to have Jenson Button out again 'very soon'. The team said that 'there were a number of things we had to check and some issues we had to address, which took some time'. They promise more details shortly."
No sign of the McLaren on the circuit yet, so here's a picture of a beaming Fernando Alonso stood behind the iconic McLaren MP4/4 from the 1988 season.
Lewis Hamilton completes an 11-lap stint on medium tyres, with the majority of those laps either 1:27s or 1:28s.
Sebastian Vettel also completes a flurry of laps, heading in after his 16th in succession with those averaging in the 1:29s. He is closing in on a century of laps for the day and it is looking like being another pleasing outing on the circuit for Ferrari, despite his spin right at the start of the day.