Heater not working on Porsche 991. Help please

[Polome]

Hi. Can't raise this in Porsche section as no " start new topic" on Porsche section heading bar.
Just driven 40 miles today...freezing cold...heater fans and directional flaps all work ok but no heat whatsoever...fans only bringing cold outside air into car....booked into Porsche on Friday...anyone help meantime as long journey's in next few days.....cheers. Ian

[IanCress]

I have no specific knowledge on the 991 but ensure that coolant levels are topped up and the coolant is flowing as it should (pipes getting hot etc). No heat could mean there's no coolant flowing and you're at risk of cooking the engine.

[Polome]

IanCress said:

I have no specific knowledge on the 991 but ensure that coolant levels are topped up and the coolant is flowing as it should (pipes getting hot etc). No heat could mean there's no coolant flowing and you're at risk of cooking the engine.

Thanks for the quick reply....had already checked the coolant level and all ok...I also removed the under boot battery cover but didn't see anything obvious ...Unfortunately the heater water pipes are tucked right down behind the battery and even my scrawny fingers couldn't reach to check for temparature or flow! ....Hope for better weather until Friday...cheers

[foresterlad]

Had the same issue on my previous 991 and it turned out to be a valve not opening after the summer. An easy fix in my case
under warranty. Technician said it was a known issue.
The following month the heater fan stopped and this was also "a known issue". Hope you get it sorted.

[rbh]

I had a similar problem on my 991.1 it was a faulty solenoid that was replaced under warranty

Edited by rbh on Friday 2nd November 15:10

[oddball1313]

More significantly it’s the coil operating the valve. Had two blown on the 991’s had, one controlled the exhaust valve which made it sound like a tractor and the second caused this issue.

[DJMC]

I had this in my 981 back in March. In the 981 it's a known problem of an under bonnet fan sticking. It can be freed by hand if you know where it is. I appreciate the 911 may well be different.

I stopped for ten minutes, restarted, and it worked again.

OPC and PGB said that unless the issue is repeatable they won't replace anything, but they've noted the issue. Under extended warranty.

[foresterlad]

Same on the 991. Porsche apparently tell OPC to do a software update after the fan sticks first time as well as freeing the motor but will consider replacing if subsequently problem repeats

[frozen-in-wiltshire]

rbh said:

I had a simple problem on my 991.1 it was a faulty valve that was replaced under warranty

This - same as mine - dealer said common problem and regularly replacing - mine done under warranty a year back - sounds exactly like yours - valve issue.

[frozen-in-wiltshire]

update:

mine was definitely a faulty valve - known issue on 991 - replaced under warranty - not a fan.
sticking fans an issue on other vehicles and 991's but not mine - mine was blowing cold air great - just no hot air (so fan was working but no heat) so mine definitely a valve issue. really common apparently and a warranty replace job - think they might even fix out of warranty as it's a known issue on 991's

hope that helps

[DJMC]

My 981 was blowing cold air too? I assumed the sticking fan under the bonnet was additional to the cabin blower. If there's just one fan, the one known to stick, then that can't have been the issue I had? Hmmmm.... odd.

[GG33]

There is a thermostatically controlled valve within the actual water pump that could also be the cause. Should be fixed under warranty.

[Polome]

Got the car back form OPC today...a vac operated valve had failed ( common fault I believe) Its purpose to directed flow in cooling system to aid fast warm up and reduce emissions. All's well now although I have to dial in a higher temperature than I would expect I.e. 25 deg C to be comfoartable whereas my other car 21 deg C would be my normal selection. Car returned spotless looking brand new inside and out..my Edinburgh OPC always been a first class one stop for me....thanks for all posts and offers of advice. Cheers.