Mercedes 'too optimistic' with radiator size amid cooling woes

Mercedes F1 in action in Austria

Mercedes’ overheating problems in Austria were caused by the manufacturer being “a bit optimistic” with the size of its radiators inside the W10.

Mercedes suffered from overheating problems throughout the Austrian Grand Prix weekend, prompting the team to open up bodywork on its W10.

Its plight was accentuated by exceptionally hot ambient temperatures, contributing to Valtteri Bottas taking third and Lewis Hamilton only fifth.

“Fundamentally the car doesn’t have big enough radiators and that’s something that we were a bit optimistic with how much we could get out of the cooling system,” said trackside engineering director Andrew Shovlin.

“It’s underdelivered to what we hoped we could achieve, and it’s meant that we are carrying this issue where in the very hot races we will be struggling to keep everything cool enough.

"You can increase the amount of cooling you get out of the car by opening up the bodywork exits and in Austria it was 35 degrees, that actually put us at the upper end of what we could achieve just by opening the car up. So, we were on limit.

“When you get to that point you are really limited in your options. You can start to use lift and coast, which is where the drivers get towards the end of the straight and they back off the throttle.

“They then brake a bit later and you have a period where the car is just coasting into the corner, the engine is not doing work and you can lose a fair bit of temperature like that.

"But, as you saw in the race, we were having to ask our drivers to increase that to around 400 metres per lap and that is why they were so compromised on performance.

“You can also turn the engine down a bit, then it will generate less heat, but you’ve got less power and you are slower on the straights.”

Shovlin confirmed that Mercedes is working on alleviating the problem for future grands prix.

“So, it was definitely a significant limitation in Austria,” he said.

“We are working on systems, we were working on them before Austria, to try and improve this problem and we should be in a better position.

“But, it all really goes down to the fundamental design of the car, where in the push for very, very tight packaging, we have ended up being undercooled overall.”