# Preventive car maintenance: ounce of prevention, or more money than brains? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 27, 2019, 4:13pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552 "2019-10-27T16:13:36Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 27, 2019, 4:13pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/1 "2019-10-27T16:13:36Z")
So, new to me is a 2006 Nissan Xterra S 4x4 with 78k miles on it. (Coming soon.) Mechanical inspection revealed no significant issues except a weeping oil pan gasket (not dripping) and a fan belt that is a bit shiny. Runs and stops great. No other issues identified by independent mechanic inspection. The car is for my son who is stationed in New England and needs a reliable vehicle for the next few to five years that will get him around the base and immediate vicinity, with the occasional 8 hour trip home, as leave allows. Now, I’m obsessive about preventive vehicle maintenance. I keep my cars for 10-20 years and keep them in as perfect working order as possible, and as close to factory spec as possible. So before I hand him the keys, I am considering doing the following maintenance: - Radiator/Transmission cooler bypass because these cars have a design flaw that may allow coolant to be forced into the transmission and causing catastrophic failure. There is an easy fix for it and so that’s item #1 on the list. Then, the following: - Oil and filter - Air filter and cabin filter - Flush: transmission fluid, diff fluid, coolant, brake lines - Brakes and pads are reported to be in good order so will leave them alone if that’s the case - Replaces all coolant and heater hoses - Replace thermometer and gasket - Replace spark plugs - Replace ignition coil packs - Replace fan belt What else should I consider checking and replacing for peace of mind? Or am I going above and beyond for no good reason? ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [October 27, 2019, 4:28pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/2 "2019-10-27T16:28:36Z")
> [@QuickSilver](#): > > So, new to me is a 2006 Nissan Xterra S 4x4 with 78k miles on it. (Coming soon.) > > Mechanical inspection revealed no significant issues except a weeping oil pan gasket (not dripping) and a fan belt that is a bit shiny. Runs and stops great. No other issues identified by independent mechanic inspection. > > The car is for my son who is stationed in New England and needs a reliable vehicle for the next few to five years that will get him around the base and immediate vicinity, with the occasional 8 hour trip home, as leave allows. > > Now, I’m obsessive about preventive vehicle maintenance. I keep my cars for 10-20 years and keep them in as perfect working order as possible, and as close to factory spec as possible. > > So before I hand him the keys, I am considering doing the following maintenance: > > - Radiator/Transmission cooler bypass because these cars have a design flaw that may allow coolant to be forced into the transmission and causing catastrophic failure. There is an easy fix for it and so that’s item #1 on the list. > > Then, the following: > > - Oil and filter > - Air filter and cabin filter > - Flush: transmission fluid, diff fluid, coolant, brake lines > - Brakes and pads are reported to be in good order so will leave them alone if that’s the case > - Replaces all coolant and heater hoses > - Replace thermometer and gasket > - Replace spark plugs > - Replace ignition coil packs > - Replace fan belt > > What else should I consider checking and replacing for peace of mind? Or am I going above and beyond for no good reason? most of those make sense, especially if you don’t know when the last time they’ve been done is (if ever.) I’d probably just give the brakes a visual inspection; as long as there’s sufficient meat on the pads _and they’re all wearing evenly_ I’d leave them be. Brake fluid flush is up to you, but it doesn’t clear out any sediment that might have formed and collected in the caliper bores. I did a flush the last time I did my Ranger’s brakes, but I was replacing all of the calipers at the same time. Usually hoses last a lot longer than 78k but if you’re opening up the cooling system anyway might as well. Don’t know if I’d bother with the thermostat and coil packs, though. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [October 27, 2019, 4:32pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/3 "2019-10-27T16:32:18Z")
The car has a maintenance checklist: [https://www.nissanusa.com/pdf/techpubs/2006/2006\_N\_SMG.pdf](https://www.nissanusa.com/pdf/techpubs/2006/2006_N_SMG.pdf) Go through it. For lots of the things you talk about replacing lots of us would simply inspect and only replace if it looks bad or weak or working poorly… ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 27, 2019, 4:56pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/4 "2019-10-27T16:56:03Z")
> [@PastTense](#): > > The car has a maintenance checklist: > [https://www.nissanusa.com/pdf/techpubs/2006/2006\_N\_SMG.pdf](https://www.nissanusa.com/pdf/techpubs/2006/2006_N_SMG.pdf) > > Go through it. > > For lots of the things you talk about replacing lots of us would simply inspect and only replace if it looks bad or weak or working poorly… Yep, that’s a good reference. At minimum I will be doing those things itemized in the service manual. Since I don’t know the full service history, I’m erring on the side of caution. How, for example, do you tell if the diff fluid is still good or already bad? ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [October 27, 2019, 5:09pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/5 "2019-10-27T17:09:21Z")
> [@QuickSilver](#): > > Yep, that’s a good reference. At minimum I will be doing those things itemized in the service manual. Since I don’t know the full service history, I’m erring on the side of caution. > > How, for example, do you tell if the diff fluid is still good or already bad? usually the only ways it goes “bad” is if it’s overheated or contaminated (typically with water.) if it’s been overheated it will be darker and smellier than normal. water contamination will make it lighter and milky in color. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 27, 2019, 5:23pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/6 "2019-10-27T17:23:10Z")
> [@jz78817](#): > > usually the only ways it goes “bad” is if it’s overheated or contaminated (typically with water.) if it’s been overheated it will be darker and smellier than normal. water contamination will make it lighter and milky in color. So the mechanic wasn’t kidding when he said he did the “smell my finger” test and it seemed fine. 🙂 ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [October 27, 2019, 5:27pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/7 "2019-10-27T17:27:54Z")
> [@QuickSilver](#): > > So the mechanic wasn’t kidding when he said he did the “smell my finger” test and it seemed fine. 🙂 gear oil stinks because the extreme pressure (EP) anti shear additives have a lot of sulfur in them. if it has a moderate “rotten egg” smell, that’s about normal. if it smells like scorched rotten eggs it’s been overheated. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [October 27, 2019, 5:47pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/8 "2019-10-27T17:47:36Z")
> [@QuickSilver](#): > > - Replaces all coolant and heater hoses You’ll probably do fine with “Inspect; replace unless looking sound.” > [@](#): > > - Replace thermometer and gasket You may mean “thermostat”. If so, these rarely go bad and can be a nuisance to change, so replace only if you see symptoms of a problem. > [@](#): > > - Replace spark plugs > - Replace ignition coil packs In typical modern ignition systems these last amazingly long - so again “inspect; replace if bad” is the way to go. > [@](#): > > - Replace fan belt In common with most newer cars, this model has a serpentine belt that drives a bunch of accessories; it may last a long time, but should probably not be asked to. So replace unless it’s obviously in excellent condition. > [@](#): > > What else should I consider checking and replacing for peace of mind? Tires. (In New England, consider good quality snow tires for November - March.) Shocks / struts. Steering components. Alignment. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 27, 2019, 6:04pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/9 "2019-10-27T18:04:42Z")
> [@Xema](#): > > You may mean “thermostat”. If so, these rarely go bad and can be a nuisance to change, so replace only if you see symptoms of a problem. :smack: > [@Xema](#): > > In typical modern ignition systems these last amazingly long - so again “inspect; replace if bad” is the way to go. Probably will do the plugs but leave the ignition coils alone. > [@Xema](#): > > In common with most newer cars, this model has a serpentine belt that drives a bunch of accessories; it may last a long time, but should probably not be asked to. So replace unless it’s obviously in excellent condition. It was noted as having some wear on the inspection, so on the list. > [@Xema](#): > > Tires. (In New England, consider good quality snow tires for November - March.) Tires are brand new, all season, balanced. Not a brand I’d have gone with but he won’t have a place to keep 2 sets of tires so we’ll see how they fair through the winter. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [October 27, 2019, 8:14pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/10 "2019-10-27T20:14:39Z")
The obvious question is why a 13 year old car only has 78K miles on it? While one possibility is that the owner didn’t drive much the other possibility is that it was driven normally for a few years and then basically sat around for a few years. If the latter then things could be worse than they look–rubber parts for example. I would specifically look to see if you can find a date on the battery or perhaps take the battery in for a test at one of the auto parts stores. Poor batteries seem fine in normal weather if the engine quickly starts, but can quickly run out of juice in very cold weather. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [October 27, 2019, 11:13pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/11 "2019-10-27T23:13:52Z")
IME the engine compartment plastics get brittle over time. I’d expect collateral damage (hose connectors & such) if you get too aggressive in there. Thermostat is probably fine, esp given the mileage on the car. Last thermostat I saw was behind the water pump. Water pump has to come off…it’s a PITA. I once replaced the transmission fluid in an old Camry because I thought it would be responsible. It whined ever since. As mentioned, a brake fluid flush won’t displace an sediments. But BF loves to absorb water from the atmosphere. Water in the BF can turn to steam and basically no brakes. So there’s absolutely nothing wrong with fresh juice. But overall I like the list. Maybe overkill, maybe not. The value of the work isn’t about dollars, it’s about how much better you feel about how you’re doing as a dad. ---
**Author:** ![sps49sd](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@sps49sd](https://boards.straightdope.com/u/sps49sd)\ **Post date:** [October 27, 2019, 11:25pm UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/12 "2019-10-27T23:25:01Z")
If the thermostat can be replaced relatively easily, I would change it. I lost a head gasket from a thermostat that did not open. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 28, 2019, 12:21am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/13 "2019-10-28T00:21:48Z")
> [@Inigo\_Montoya](#): > > The value of the work isn’t about dollars, it’s about how much better you feel about how you’re doing as a dad. Fuck. Really? Okay. I’ll throw in some new rubber floor mats and a pine air freshener, too. ---
**Author:** ![Sunny\_Daze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunny_daze/32/438_2.png) [@Sunny\_Daze](https://boards.straightdope.com/u/Sunny_Daze)\ **Post date:** [October 28, 2019, 12:27am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/14 "2019-10-28T00:27:40Z")
New wiper blades. I agree that although the car has low mileage, you should be cautious with parts that age poorly (gaskets, hoses, belts). Do you know if the vehicle was ever used for towing? That can potentially wear on parts as well. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [October 28, 2019, 12:29am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/15 "2019-10-28T00:29:05Z")
And windshield washer fluid. Papa. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 28, 2019, 12:37am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/16 "2019-10-28T00:37:57Z")
> [@Sunny\_Daze](#): > > New wiper blades. For sure. Battery jump-starter, snow brush and shovel as well. > [@Sunny\_Daze](#): > > Do you know if the vehicle was ever used for towing? That can potentially wear on parts as well. I have no idea and no way to find out except to maybe look for wear on the trailer hitch. I suppose if there is additional wiring for a trailer that looks used, that would be another tell. So that’s another thing to keep me up in the middle of the night. Awesome. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [October 28, 2019, 12:41am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/17 "2019-10-28T00:41:37Z")
> [@Inigo\_Montoya](#): > > And windshield washer fluid. Papa. Yes, yes… and spare oil and coolant… Why are you fucking with me right now? ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [October 28, 2019, 2:05am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/18 "2019-10-28T02:05:47Z")
With 78K miles, I’d be worried about the timing belt. Unless this is one of those vehicles with a timing chain. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [October 28, 2019, 7:27am UTC](https://boards.straightdope.com/t/preventive-car-maintenance-ounce-of-prevention-or-more-money-than-brains/842552/19 "2019-10-28T07:27:30Z")
> [@Chefguy](#): > > With 78K miles, I’d be worried about the timing belt. Unless this is one of those vehicles with a timing chain. chain.