# Alternator failure and mileage? **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [May 11, 2025, 5:49pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220 "2025-05-11T17:49:08Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 9, 2025, 3:58pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/62 "2025-06-09T15:58:56Z")
> [@db4690](#): > > imo, the coil is not the cause, but rather a symptom of the problem > > perhaps you’ve got a leaking spark plug tube seal and that’s why that particular coil boot appears different Wondering if you notice my post saying the spark plug was not screwed on! Wondering if the car could have still run without throwing a CEL - which it did! ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 9, 2025, 6:28pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/63 "2025-06-09T18:28:55Z")
Anyone has a good video on replacing the boots specific to this Denso/Corolla 2009? I checked Youtube: - some have tapering springs - but in my case, photo of the spring looks symmetrical - one in the video talked about aligning with a vent hole - so I am cautious about these nuances - another talks about di-electric grease - world seems to have moved away from manual application of grease! I could not find the manual online for DENSO 671-4318 > **[More Information for DENSO 6714318](https://www.rockauto.com/en/moreinfo.php?pk=8815844&cc=1442416&pt=10150&jsn=10)** Thank you ---
**Author:** ![jtsanders](https://avatars.discourse-cdn.com/v4/letter/j/c2a13f/32.png) [@jtsanders](https://community.cartalk.com/u/jtsanders)\ **Post date:** [June 9, 2025, 7:24pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/64 "2025-06-09T19:24:48Z")
Is this what you want? [![](https://global.discourse-cdn.com/cartalk/original/3X/e/5/e5d688551dd46994341333f89172be6f5256ae9a.jpeg "Toyota Ignition Coil Boot") ](https://www.youtube.com/watch?v=oXdfJLRbPQI) ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 9, 2025, 9:27pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/65 "2025-06-09T21:27:20Z")
Denso replied me: - apply di-electric to the internal insulator tube and spark plug terminal. Beyond that there is no orientation my case. ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [June 10, 2025, 5:29am UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/66 "2025-06-10T05:29:37Z")
> [@sciconf](#): > > Denso replied me: > > - apply di-electric to the internal insulator tube and spark plug terminal. > > Beyond that there is no orientation my case. The dielectric grease is to lock out moister and to keep the boots from sticking to the spark plugs down the road the next time you go to remove the COP’s… This is what can/will happen if you don’t use dielectric grease inside the tips of the boots… PITA!!! ![image](https://global.discourse-cdn.com/cartalk/original/3X/6/a/6ae19384b1d9baa5f61b899112915da61bfd2782.jpeg) ![Screenshot 2025-06-10 002402](https://global.discourse-cdn.com/cartalk/original/3X/f/f/ff8969acd01d560ca065122ab4b52740d0128cfa.jpeg) ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 11, 2025, 6:35am UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/67 "2025-06-11T06:35:53Z")
> [@Nevada\_545](#): > > If the engine is cranking but will not start, the first suspicion would be insufficient fuel pressure. How long did you crank the engine before giving up on starting the engine? June 10th: While the car runs much smoother with the new sparks, car didn’t start the 1st time today around 5pm - it was driven from 9am. It started the 2nd time without jump start or pressing the gas pedal - well it started on its own. What things that I should focus on in troubleshooting the issue! Measuring fuel pressure? But will it be conclusive on an intermittent issue? When it happened the 2nd time on Sat, we tried about 6 times before jump starting it. **Update:** June 11th Happened again in the early morning. Several attempts and pressing the gas pedal didn’t go anywhere. Tried again after 5mins and it started. I am a bit clueless. Battery passes the test but its about 4yrs old. If it were Honda, I would have gone for the Fuel Injectors. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [June 12, 2025, 2:03pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/70 "2025-06-12T14:03:01Z")
> [@sciconf](#): > > car is moving to East cost - conditions are likely severe in East cost. I do not want my family member to be stranded I got flagged to reminding responders of this. ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 12, 2025, 4:45pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/71 "2025-06-12T16:45:43Z")
> [@Nevada\_545](#): > > > [@sciconf](#): > > > > Battery measured 12.56v - when cranking it went down to 11.23v and wouldn’t start. > > If the engine is cranking but will not start, the first suspicion would be insufficient fuel pressure. How long did you crank the engine before giving up on starting the engine? - No CEL. Once started car drives smooth. If the fuel pressure issue, it should have stalled or triggered CEL - pls correct me if I am wrong? - it cranks and battery voltage is 11.23V - another time it went to 10.5v. Either case, jump start worked. **Does this mean starter motor is drawing more current and causing the issue?** - Other thoughts: Crank/cam sensor - may not trigger CEL My trusty m/c told me he is closed for rest of the week. There are so many shops but with bad reviews or too busy to take the car in. **Intermittent issue is hard**! Nice video but again mine is intermittent: [https://youtu.be/-sLFNi1drc4](https://youtu.be/-sLFNi1drc4) ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [June 12, 2025, 5:01pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/72 "2025-06-12T17:01:08Z")
> [@sciconf](#): > > it cranks and battery voltage is 11.23V - another time it went to 10.5v. Either case, jump start worked. Is as measured while cranking?? or after cranking has stopped and you go out and check B volts?? Measure your voltage before cranking \> during cranking \> after cranking, and report back to us… I am curious what it is when it does not start only… Also with a fully charged battery, turn in your head lights for 10-15 minutes (key off) and after the 10-15 minutes is up, check volts and see if it will start… You should be able to leave your lights on for about 30 minutes and the vehicle still start… Or use a battery load tester for this… These new fancy testers don’t always catch a bad/failing battery… ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 12, 2025, 5:15pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/73 "2025-06-12T17:15:13Z")
> [@davesmopar](#): > > > [@sciconf](#): > > > > it cranks and battery voltage is 11.23V - another time it went to 10.5v. Either case, jump start worked. > > Is as measured while cranking?? or after cranking has stopped and you go out and check B volts?? I measured before cranking, during cranking but never right after. Before cranking mostly 12.56. During it was 11.23v and another time 10.5v. After several cranking it was 12.44V (this could be after cranking that you were asking - but not right after). I will give it a try on manual load test of the battery. ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 13, 2025, 4:14am UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/74 "2025-06-13T04:14:21Z")
> [@davesmopar](#): > > Measure your voltage before cranking \> during cranking \> after cranking, and report back to us… I am curious what it is when it does not start only… I did 2 measurement 30mins after an 80mile drive. Engine is off: 12.78v Engine is running: 13.78v Turn off the engine: voltage was slowly dropping - I measured just over 13v. I did not hold long enough for it to come down to 12.78v **Update:** After over night cooling, its 12.67v Issues: **May 11** after a car wash - batt voltage was little low - jump started **June 7th** after BFluid flush at a shop - we drove off from shop fine but happened at the next stop - voltages were fine - cranking v was 11v.- jump started after several tries. **On June 8th one spark was found lose**. All sparks replaced with Denso **June 10th** - 5pm - minor issue - started on the 2nd try - no jump start **June 11th** - 9am - multiple tries - paused for 5mins and it started - - no jump start No DTC, no CEL **Load test:** 14 or 15mins of head light on. Turned it off and car started fine. **4yr old** battery **Pending repair: Serpentine belt** as it slips when starting, occassionally ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 14, 2025, 11:16pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/75 "2025-06-14T23:16:19Z")
**So what product/brand Starter Motor should I get?** I was also looking at RockAuto and O’Reilly/Napa (doing 20% off)? Amz has one for $60! Appreciate your tips. Thank you Twice it made a eerie sound while starting - 2nd time happened in front the mechanic. He rushed to me and told me its the starter. So seems **case is closed - its the starter motor!** ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 14, 2025, 11:37pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/76 "2025-06-14T23:37:57Z")
Install a Denso starter. That’s what came in the car originally. Tester ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 14, 2025, 11:39pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/77 "2025-06-14T23:39:27Z")
> [@Tester](#): > > Install a Denso starter. > > That’s what came in the car originally. > > Tester Rock auto has Reman - is that good enough? Thank you @Tester ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 14, 2025, 11:46pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/78 "2025-06-14T23:46:52Z")
I don’t know who remanned the starter. So I can’t say. Tester ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [June 15, 2025, 12:00am UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/79 "2025-06-15T00:00:11Z")
> [@sciconf](#): > > Twice it made a eerie sound while starting - 2nd time happened in front the mechanic. He rushed to me and told me its the starter. You just needed someone with good hearing to tell you the starter is failing. ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 15, 2025, 5:33pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/80 "2025-06-15T17:33:20Z")
> [@Nevada\_545](#): > > You just needed someone with good hearing to tell you the starter is failing. Contrary to that **Experience** is all that required. I ignored it the 1st time because of existing belt slipping sound I hear though it was different and longer duration. I only had to change Starter on a 25yr old Honda despite I had 5 Hondas - 2 of which had over 150k miles. Almighty reliable Toyota Corolla has some weak points as I realize - all three below affected me in a short 18months 20k miles usage: - Starter Motor - Sway bar link - a plastic connector in the coolant piping that breaks - they have made aluminum after market part Here is what AI says about Starter: _The starter motor on a 2009 Toyota Corolla typically lasts between 100,000 and 125,000 miles before failure is common. This aligns with general expectations for car starters, which usually last between 100,000 and 300,000 miles depending on usage and conditions_ _.While most 2009 Corollas experience starter issues after 100,000 miles, early failure can occur due to several factors:_ _Faulty starter solenoid_ _Damaged conductor brushes_ _Bad starter relay_ _Loose or corroded wiring_ _Frequent short trips or harsh driving conditions_ ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [June 15, 2025, 5:57pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/81 "2025-06-15T17:57:01Z")
Hard to keep quite about wow high mileage when I think of my 530k Buick with the engine never opened up. Or my other 350k Buick. Or my 480k olds, or my 240k olds, or or. . .just sayin is all. ---
**Author:** ![jtsanders](https://avatars.discourse-cdn.com/v4/letter/j/c2a13f/32.png) [@jtsanders](https://community.cartalk.com/u/jtsanders)\ **Post date:** [June 15, 2025, 6:36pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/82 "2025-06-15T18:36:32Z")
> [@bing](#): > > Hard to keep quite about wow high mileage when I think of my 530k Buick with the engine never opened up. Or my other 350k Buick. Or my 480k olds, or my 240k olds, or or. . .just sayin is all. Don’t hurt your arm patting yourself on the back. 😊 ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [June 15, 2025, 7:42pm UTC](https://community.cartalk.com/t/alternator-failure-and-mileage/200220/83 "2025-06-15T19:42:20Z")
> [@bing](#): > > Hard to keep quite about wow high mileage when I think of my 530k Buick with the engine never opened up. Or my other 350k Buick. Or my 480k olds, or my 240k olds, or or. . .just sayin is all. For me its the 1st and 3rd gen Integras. Not so much about mileage as @bing says - I do not drive that much. Its the design, handling, looks, convenience of the 1st gen hatchback (it was a motorbike, mini van all in one package). I guess Honda moved from Motor bikes to cars! If I see one with low mileage or re-built, I will be tempted - what it lacks is the mpg in todays world. [Previous page](https://community.cartalk.com/t/alternator-failure-and-mileage/200220.md?page=3) [Next page](https://community.cartalk.com/t/alternator-failure-and-mileage/200220.md?page=5)