Smart Forfour, Renault Twingo - Where does cabin air enter in Twingo/Forfour?

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Sun 11 Oct 2020 13:01
Smart Forfour, Renault Twingo - Where does cabin air enter in Twingo/Forfour? - Starman999

I can't ask my question without some preamble. Still, I'll be as succinct as I can!

I suffer from extreme Multiple Chemical Sensitivity. In a nutshell, this means that I respond physically to the tiniest amounts of airborne toxins - amounts other people would never even slightly react to. So I get very unwell in a great many cars as the tiniest whiff of anything coming from an engine will affect me badly.

I know that (in a front engine car, at least) the air intake for the cabin is right next to the engine, and my perception is that once an engine is a bit old, there will always be some airborne 'nasties 'from the engine that will get inside. Although there is a barrier between the air intake and the engine - this barrier does not appear to be air tight in many cars and, as mentioned, the tiniest amount of 'oily fumes' will make me ill.

So the thought struck me that a rear engine car might suit me better. That is, it will suit me better IF having the engine in the rear means that the cabin air will NOT then come via a route that's next to the engine.

So my essential question is: Where does the cabin air enter on a Renault Twingo or a Smart ForFour? Does it take an 'airtight' route without being in proximity to engine fumes? And what about if the heater's being used? Thanks in advance.

Edited by Starman999 on 11/10/2020 at 13:29

Reply | Report as offensive | Link
Sun 11 Oct 2020 14:00
Smart Forfour, Renault Twingo - Where does cabin air enter in Twingo/Forfour? - daveyjp

The pollen filter and heater matrix (HVAC unit) is located at the front underneath the dashboard, in front of the gearstick, this is directly under the front fresh air intakes.

Hot water is provided from the engine to the HVAC unit, but I can't see how engines fumes would be transferred from back to front.

The engine is well sealed under the boot floor. Carpet first then a cover plate which has to be unscrewed to gain access.

However like many rear engine vehicles having the engine in the rear and HVAC unit some distance away does mean it takes ages to get warm air into the cabin. This has been an issue with smarts from the very first ones. Some owners use plumbers pipe insulation on the heating circuit pipework to reduce heat loss.

Reply | Report as offensive | Link
Sun 11 Oct 2020 14:10
Smart Forfour, Renault Twingo - Where does cabin air enter in Twingo/Forfour? - Starman999

@daveyjp
Thanks a lot! Sounds like it could be a good bet for 'sensitive me'.

So are the front air intakes the ONLY air intakes?

Edited by Starman999 on 11/10/2020 at 14:14

Reply | Report as offensive | Link
Sun 11 Oct 2020 19:49
Smart Forfour, Renault Twingo - Where does cabin air enter in Twingo/Forfour? - daveyjp

There is an air intake on the rear nearside panel for the engine airbox, this goes into the air filter, not the cabin.

Reply | Report as offensive | Link
Sun 11 Oct 2020 21:18
Smart Forfour, Renault Twingo - Where does cabin air enter in Twingo/Forfour? - Starman999

@daveyjp Got it. Thanks a million for your help.

Edited by Starman999 on 11/10/2020 at 21:19

Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide