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Hi everyone,
Many modern cars come with stop-start technology to improve fuel efficiency, but I’m curious about its long-term effects. Does frequent engine restarting increase wear on critical components like the starter motor and crankshaft? Also, how does it impact battery lifespan, and are there specific maintenance tips to prolong system durability?
Looking forward to your insights!
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I have always assumed the components that do extra work in stop-start systems are designed to cope. Certainly batteries designed for stop-start use have a particular specification.
I have no idea why some drivers switch stop-start off; in my Mazda CX-5 it works more or less seamlessly and I'm happy to accept the lower emissions and enhanced efficiency.
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That’s a great point! Modern stop-start systems are indeed designed with durability in mind, and the benefits in fuel efficiency and emissions reduction make them worth using. Some drivers may disable it due to personal preference or past experiences with less refined systems.
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"That’s a great point! Modern stop-start systems are indeed designed with durability in mind, and the benefits in fuel efficiency and emissions reduction make them worth using. Some drivers may disable it due to personal preference or past experiences with less refined systems."
I'd put money on this being AI-generated.
Another thread started by "Jane Will" has disappeared, I see.
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The Mazda system is excellent though, mine has restarted before I've even fully pushed the clutch in. Very quick and seamless. I only replaced the original battery last month at nearly 9 years old, not because it had failed, but as a precaution as its capacity had dropped. It would seem start-stop didn’t really have too much of an impact as it had outlived the typical expected lifespan for a lead acid battery.
I've never held the opinion that start stop exists to save owners money, although that is a welcome side effect. Rather it’s an anti-pollution system to alleviate emissions in built up city gridlock.
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I've recently sold my 2014 1.4tsi Superb mkII with stop start that has done about 130k miles and I've always used stop/start except for a few months when the original battery was on its way out and it no longer did stop/start. When sold it still drove like new with no issues re starter/charging but the original Moll stop/start battery only lasted 6 years. In contrast with my previous non s/s 2003 mkI Superb pd owned for a decade - it left my ownership with its original Varta battery, and the battery lasted a few more years !
My Swace (Toyota 1.8 hybrid gubbins) frequently stops using the engine during a journey and those engines are well regarded re longevity. No starter motor/ring gear etc though.
Most engines if they are warm and have been running will remain primed with oil if they are stopped briefly.
The quality of the AGM or EFB battery is probably key for the more traditional stop/start and replacements must be correctly coded into the car.
Edited by Big John on 17/02/2025 at 21:29
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Your still letting oil drain back to the sump from the top of the engine, then expecting the oil pump to get it all back up there pronto.
Perhaps dozens of times per journey, instead of once.
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Your still letting oil drain back to the sump from the top of the engine, then expecting the oil pump to get it all back up there pronto.
Perhaps dozens of times per journey, instead of once.
Unless engine is already cream crackered oil will remain primed in the critical bearings such as main/bigend/smallend/cam/turbo for a few mins surely?
Actually back in the day when I'd stripped down many an engine residual oil could disguise wear when evaluating eg waggling big end caps etc - and that's after some time!
I'd say the most likely candidate re damage might be the turbo (be it oil or too hot) as it's on the extremities.
Edited by Big John on 17/02/2025 at 22:29
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Your still letting oil drain back to the sump from the top of the engine, then expecting the oil pump to get it all back up there pronto.
It takes hours for oil to drain down enough to affect lubrication in a warm engine ! That's why you should wait 10 minutes before reading the dipstick.
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Conversely, you used to be advised to idle-down a turbo equipped engine, to avoid cooking the oil left stationary in the hot turbo.
Not going to happen with stop start, but I suppose stop-start wont happen much in a high speed turbo-toasting run.
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Conversely, you used to be advised to idle-down a turbo equipped engine, to avoid cooking the oil left stationary in the hot turbo.
So presumably stop-start and hot turbos don't really go together ? Tho I suppose if the car has come to a planned stop, it suggests that the turbo may not be all that hot ....
Edited by Andrew-T on 18/02/2025 at 10:55
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Stop start has several parameters that need to be met to operate. I am pretty sure my Golf won’t let it stop if the turbo is hot but someone here will know for sure.
Of course there is nothing to stop you actively turning off the engine whether you have stop start or not. I try to let mine simmer for a short time when pulling into services on a motorway. I don’t always remember and hopefully the slow speed as I find a space is going to dissipate the worst heat. I bet most drivers don’t bother to try.
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Stop start has several parameters that need to be met to operate. I am pretty sure my Golf won’t let it stop if the turbo is hot but someone here will know for sure.
Of course there is nothing to stop you actively turning off the engine whether you have stop start or not. I try to let mine simmer for a short time when pulling into services on a motorway. I don’t always remember and hopefully the slow speed as I find a space is going to dissipate the worst heat. I bet most drivers don’t bother to try.
Many turbos are water-cooled and some installations have an electric water pump which may keep running when the engine stops if ECU decides it needs to.
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The cynic in me is thinking that these problems won't appear until after year 3 - just after the manufacturer's warranty has expired!
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The cynic in me is thinking that these problems won't appear until after year 3 - just after the manufacturer's warranty has expired!
My VW Touareg has stop-start - it's lasted 9.5 years so far without any issue - the expensive battery was replaced at 8 years, considering that VW recommend replacement at 5 years.
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A son has a 3+ year old Audi A6 V8.
He has had a few electrical issues in the last 6 months - sensors in the main, faulty door lock on rear door, lots of dashboard lights.......
However, in January the BGS packed in Belt, Generator & Starter -part was foc as it is a known problem - about £1500 to buy and labour is pricey due to the need to strip away large parts under the bonnet to get access.
Instead of a recall, and not having parts, they wait for the unit to fail and then fit a new/uprated part.
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A son has a 3+ year old Audi A6 V8.
However, in January the BGS packed in Belt, Generator & Starter -part was foc as it is a known problem - about £1500 to buy and labour is pricey due to the need to strip away large parts under the bonnet to get access.
BGS is part of the mild hybrid 48v setup I think. I've been trying to avoid myself which is why I've jumped from a more traditional manual car with 12v starter motor stop / start to a Toyota based full petrol/electric hybrid. I dare say in a few years (I usually keep cars for about a decade) the next step will be an electric car but for now...... I'll let the car market settle!!
How things come back around - some friends of mine have an early 1920's Morris Bullnose that has a permanently engaged chain drive generator / starter. Not effective starting a cold engine really but it starts a warmish engine without the noise of a traditional starter motor - just the whoosh of compression.
Edited by Big John on 21/02/2025 at 22:28
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I try to let mine simmer for a short time when pulling into services on a motorway. I don’t always remember and hopefully the slow speed as I find a space is going to dissipate the worst heat. I bet most drivers don’t bother to try.
I always used to do that on my old Saab 9-5, we travelled a lot on the Autobahn between the UK and Austria so it had sometimes been running hard and fast for a few hours. The engine made 236,000 miles on the original turbo, so it obviously paid off!
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I always used to do that on my old Saab 9-5........The engine made 236,000 miles on the original turbo, so it obviously paid off!
I have a friend who used to have one of these brilliant engines in his 1980s Saab - it also did over 200,000 miles (a tribute not only to Saab turbos but also to the sturdiness of the TriumphTR7 slant4 engine;-).
www.triumphexp.com/forum/tr7-and-tr8-forum.3/saab-...n.
I sometimes wonder why other car manufacturers took so long to adopt turbos.
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I always used to do that on my old Saab 9-5, we travelled a lot on the Autobahn between the UK and Austria so it had sometimes been running hard and fast for a few hours. The engine made 236,000 miles on the original turbo, so it obviously paid off!
Indeed, warm up and cool down routines work wonders, as does good regular oil coolant etc servicing, preferably ignoring suggested long service intervals unless your motoring suits them, for most car drivers their usage doesn't.
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We've had a 'last-of-the-line' Oct 2019 Peugeot 2008 1.2 puretech 130 EAT6 Allure Premium from new. The battery is original. It only does <6,000 miles a year so fuel economy is not an issue, especially as I wanted the 'sportier' version. Since its year old 'first service' it has never been back to a garage (apart from MoT) as I service it myself. The s/s only occasionally worked to begin with and hasn't activated at all in recent years. I am delighted. I wonder how much money the battery industry and associated mechanics are making out of this enthusiastic (and in Peugeot's case, flawed) concept.
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We've had cars with stop start since my B class which was 15 years ago - 6 cars on total. Never had an issue with any of them.
Proving an electrical fault after tens of thousands of miles is due purely stop start would be very difficult to prove as cars have had starter, alternator and battery issues since well before stop start tech was fitted.
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My Hyundai i30 s/s battery failed last week, only 30k but 98% of my driving is short journeys. Bought new in 2019. Always serviced by main dealer. Had to buy AA breakdown cover online to get back on the road - £230! Never used the s/s function as I always turned it off. New battery cost me £265!!!! It’s a scam. The last I had to replace a battery was on an 8 year old Astra and it cost me £35. Start stop doesn’t improve fuel efficiency it just wears out the starter motor and battery.
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My Hyundai i30 s/s battery failed last week, only 30k but 98% of my driving is short journeys. Bought new in 2019. Always serviced by main dealer. Had to buy AA breakdown cover online to get back on the road - £230! Never used the s/s function as I always turned it off. New battery cost me £265!!!! It’s a scam. The last I had to replace a battery was on an 8 year old Astra and it cost me £35. Start stop doesn’t improve fuel efficiency it just wears out the starter motor and battery.
It clearly isn't the cause of your battery failure as by your own account, you "always turned it off". You've had 5-6 years out of the battery, which is about right.
Cars with stop-start have starter motors and batteries designed for that purpose so don't wear out any quicker.
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My Hyundai i30 s/s battery failed last week, only 30k but 98% of my driving is short journeys. Bought new in 2019. ......
You've had 5-6 years out of the battery, which is about right.
It may have been 'about right' for a last century cheapie, but not now. The first battery in our runabout 2000 Mk1 Focus lasted 6yrs. Its replacement lasted 14yrs. I wonder if Hyundai use low quality cheap components as they are notoriously cheap cars? I googled 'do Hyundai batteries fail early?' and a lot of stuff appeared to suggest this. Battery replaced in my 1980 TR7 - 1984, 1991, 1996, 2002, 2021.
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"Start stop doesn’t improve fuel efficiency it just wears out the starter motor and battery."
Sorry - you're wrong on one point and there's no evidence to support the other.
The whole point of stop-start is that the engine is not allowed to idle and therefore doesn't use fuel for a while, so of course fuel efficiency is improved.
The stop-start "hardware" is designed for the job. There's no evidence starter motors and batteries fail sooner because of it. In fact, I replaced my battery only recently, after 10½ years on a Mazda CX-5 that stands outside all year round. I leave my stop-start on permanently.
No idea why people are so prejudiced against it.
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The whole point of stop-start is that the engine is not allowed to idle and therefore doesn't use fuel for a while, so of course fuel efficiency is improved..
I thought the 'whole point' of stop-start was to reduce emissions in places with congested traffic. I doubt they will improve overall consumption much, as the power used to restart the engine has to be put back in the battery by the alternator. Depends how long each stop lasts, of course.
Edited by Andrew-T on 08/03/2025 at 23:10
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DP !
Edited by Andrew-T on 08/03/2025 at 23:09
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My Hyundai i30 s/s battery failed last week, only 30k but 98% of my driving is short journeys. Bought new in 2019. Always serviced by main dealer. Had to buy AA breakdown cover online to get back on the road - £230! Never used the s/s function as I always turned it off. New battery cost me £265!!!! It’s a scam. The last I had to replace a battery was on an 8 year old Astra and it cost me £35. Start stop doesn’t improve fuel efficiency it just wears out the starter motor and battery.
I think you are being a bit unfair on the i30.
1)Surely having breakdown cover is a good idea anyway - as mentioned on this forum other much cheaper and better options are available for a fraction of the cost of your AA breakdown - eg Startrescue - for my car with local breakdown/ homestart/ national recovery the cost would be £39.76 and you usually buy the cover before you breakdown. Cheapskate local recovery is available for about half that.
2) Six years is reasonable for a battery, back in the day with an old mkII Cortina that was always difficult to start on a cold morning from near new you were luck to get a year out of a battery. The battery on my 2014 Superb mkII s/s (original Moll ) lasted 6 years but I think lack of use during lockdown finished it off. I had a Yuasa EFB s/s battery fitted for about £100 - not from the main dealer though who were quoting much more.
Edited by Big John on 11/03/2025 at 08:57
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Had to buy AA breakdown cover online to get back on the road - £230! Never used the s/s function as I always turned it off. New battery cost me £265!!!! It’s a scam.
A case of supply and demand. If you could shop around for a new battery, it would only cost you a fraction of what the AA choose to charge, similarly for AA membership.
I imagine the same would happen to any car with a flat tyre and only a can of repair foam that doesn't cut the mustard for some reason. You either leave the car at the side of the road while you try and find a puncture repair/new tyre place at a reasonable price (while carrying the wheel) or cough up whatever extortionate price your rescuer decides to charge for some cheap tyre that you'd never consider normally.
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My Hyundai i30 s/s battery failed last week, only 30k but 98% of my driving is short journeys. Bought new in 2019. Always serviced by main dealer. Had to buy AA breakdown cover online to get back on the road - £230! Never used the s/s function as I always turned it off. New battery cost me £265!!!! It’s a scam. The last I had to replace a battery was on an 8 year old Astra and it cost me £35. Start stop doesn’t improve fuel efficiency it just wears out the starter motor and battery.
I think you are being a bit unfair on the i30.
2) Six years is reasonable for a battery, back in the day with an old mkII Cortina that was always difficult to start on a cold morning from near new you were luck to get a year out of a battery. The battery on my 2014 Superb mkII s/s (original Moll ) lasted 6 years but I think lack of use during lockdown finished it off. I had a Yuasa EFB s/s battery fitted for about £100 - not from the main dealer though who were quoting much more.
The battery on my 2009 i30 lasted 14 years, replaced because mph/rpm displays went strange and checks showed it was beginning problems. So original battery with no stop-start was good quality.
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I have had start stop on my last two cars.
On the Peugeot 308 it rarely worked as intended anyway.
On the current Ateca it works fine. Even accepting that components are designed to cope with the additional stress, I dislike the occasional judder and (more importantly) the short delay as it restarts.
Safety when entering roundabouts and emerging from junctions is compromised - real or imagined. I routinely disable it.
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Safety when entering roundabouts and emerging from junctions is compromised - real or imagined. I routinely disable it.
I find this comment quite strange.
With stop-start engaged, when you are about to move off at a roundabout or junction you wait with your foot on the clutch, in first gear. The engine keeps running. I don't see any problem.
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Safety when entering roundabouts and emerging from junctions is compromised - real or imagined. I routinely disable it.
I find this comment quite strange.
With stop-start engaged, when you are about to move off at a roundabout or junction you wait with your foot on the clutch, in first gear. The engine keeps running. I don't see any problem.
I thought the same tbh....
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With stop-start engaged, when you are about to move off at a roundabout or junction you wait with your foot on the clutch, in first gear. The engine keeps running. I don't see any problem.
Do any automatics use stop/start?
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With stop-start engaged, when you are about to move off at a roundabout or junction you wait with your foot on the clutch, in first gear. The engine keeps running. I don't see any problem.......
.....until the overused clutch release bearing fails ;-(
Do any automatics use stop/start?
Our Peugeot 2008 EAT6 does.......but it rarely happens, which is fine by me.
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".....until the overused clutch release bearing fails"
You don't think designers of stop-start technology might have considered that, along with the more robust starters and batteries which are part of it?
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".....until the overused clutch release bearing fails"
You don't think designers of stop-start technology might have considered that, along with the more robust starters and batteries which are part of it?
Would that mean that something extra might have been designed in ? Release bearings must be mature tech ?
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With stop-start engaged, when you are about to move off at a roundabout or junction you wait with your foot on the clutch, in first gear. The engine keeps running. I don't see any problem.
Do any automatics use stop/start?
Yes - my 2016 VW Touareg has it
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Safety when entering roundabouts and emerging from junctions is compromised - real or imagined. I routinely disable it.
I find this comment quite strange.
With stop-start engaged, when you are about to move off at a roundabout or junction you wait with your foot on the clutch, in first gear. The engine keeps running. I don't see any problem.
Not with an automatic!
Brake to a halt at say a roundabout. Automatically engages handbrake. Stops engine.
Depress accelerator to move off. Starts engine. Dis-engages handbrake. No big delay (under a second) but annoying and adds to uncertainty in busy traffic.
Edited by Terry W on 19/03/2025 at 13:06
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It’s the first thing I disable on my car when I start it. Years of telling people to let a turbocharged engine idle for a few seconds before turning it off are hard to forget. I also note that turbo failure is much more common on modern turbo diesels than it used to be before stop/start was a thing. Think back to the old XUD turbo diesels, VW’s PD 1900, Isuzu 1700 TD in the Astra and Cavalier, Rovers L series diesels and the predecessor in the Montego. These all ran to mega miles without turbos failing, yet more modern equivalents are far more likely to go pop before hitting 100,000 miles.
It will put more pressure on the starter, and it cuts the oil feed to the turbo which might well have been flying along at motorway speeds shortly before then suddenly it the system stops the engine dead. I’m no mechanic, but it doesn’t sound too clever to me. I don’t like it, so I turn it off. Problem solved.
Edited by SLO76 on 19/03/2025 at 20:05
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Possibly a number of factors at play so difficult to isolate any single one. I suspect long service intervals is part of it.
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Another issue that has become much more common in recent years is timing chain failures. BMW/Vauxhall/Mazda Skyactiv D/VAG TSi are among the most common. I’m fully confident that stop/start exacerbates this. Chain driven motors in the 80’s/90’s rarely went wrong, unless utterly neglected.
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Chain driven motors in the 80’s/90’s rarely went wrong, unless utterly neglected.
I had an '03 Nissan with cam chain. They were, allegedly, made from cheese. The engine only held 2.7 litres of oil. I changed it every 5K miles and never had any problems during my ownership, taking it up to 50K.
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Chain driven motors in the 80’s/90’s rarely went wrong, unless utterly neglected.
I had an '03 Nissan with cam chain. They were, allegedly, made from cheese. The engine only held 2.7 litres of oil. I changed it every 5K miles and never had any problems during my ownership, taking it up to 50K.
In reality, no engine should give issues up to 50,000 miles - even if abused and neglected.
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Chain driven motors in the 80’s/90’s rarely went wrong, unless utterly neglected.
I had an '03 Nissan with cam chain. They were, allegedly, made from cheese. The engine only held 2.7 litres of oil. I changed it every 5K miles and never had any problems during my ownership, taking it up to 50K.
In reality, no engine should give issues up to 50,000 miles - even if abused and neglected.
Eric "Ido cars" on YouTube dismantles a failed engine every week and many of these have managed 100,000 miles, usual cause is neglect by owners.
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