Design choices that create frustration during repairs

I was recently replacing the hydraulic steering lines on my truck. The frustrations there were many including line retainers that were installed before the engine and virtually impossible to remove (unless you like feeling around indefinitely with a wrench and getting 20 degrees each time) It could easily have been screwed to the side of the crossmember instead but I digress…

It’s had ongoing issues with the evap system as well. I recently replaced the vent solenoid that failed electrically and then had the dreaded small leak fault code. I suspected the purge valve but it is buried and very hard to access. However, it was much easier to access while most of the left side suspension and front driveshaft was removed :grinning: Still, it’s arms length away but you can see it and touch it. The frustration comes when disconnecting the vapor lines. The side headed toward the canister is very straightforward- just squeeze the ring around the connector with your thumb and forefinger and pull it off. Can’t be easier. Now go to the other side where the line goes to the engine. It’s some freaky arrangement with a retention clip you have to lift upward while trying to pull the line off the valve (which is fused to the valve nipple after 15 years). WTH. Why isn’t it the same kind of connector as the other side? The nipples on the valve are the same. Engineering 101- use the same hardware as often as possible to minimize inventory, maximize volume buying and minimize labor time by having all the same “stuff”.

The struggles to remove this connector apparently created more of a leak than the valve itself. Once removed, it was clear the N/C valve was not sealing completely. However, now I have a gross leak and have ordered a replacement line. But this situation is so frustrating. WHY?? :grinning:

Might be cathartic to share our various experiences with similar frustrations we have run across while doing repairs-

When it came time to change the air filter on my brother’s Datsun SPL-310, we found out–to our great annoyance–that it was impossible to do that job unless we first detached the twin side-draft carbs. That incredibly crappy little car was so badly designed that the cover for the air cleaner assembly was so close to the inner fender that it couldn’t be removed.


The Ford engineers who designed my 50 y.o. 4WD truck did a pretty good job. Most routine service & repair is diy’er doable. I guess if I had to complain about something, first would be draining & re-filling the rear differential. No drain plug in the Ford 9 inch pumpkin for some reason, so I have to unbolt the 3rd member enough to crack the gasket seal to get a good drain. Weird thing is, the front differential is equipped w/a drain plug, go figure. Second, lubing the front axle-shafts’ CV joints requires removing the entire axle-shaft to do the job well. Both of these problems are mostly just quibbles. VDC mentions above about needing to remove the carbs on the Datsun. Removing my truck’s carb for a bench look-see is easy-peasy, a 10-15 minute job.

For my 30 y.o. Corolla, first would be the location of the water pump pulley. It is right up against the offside inner fender. Removing/installing it from the water pump hub requires the engine be jacked up substantially, meaning the front engine mount and a couple of other mounts have to be free’d up first. This pulley must be removed in order to either replace the water pump or the timing belt. It’s not overly difficult to loosen the three mounts admittedly. My main worry is that jacking the engine stresses the exhaust system. Second would be any work involving stuff under the intake manifold, egr, egr modulator, egr thermistor, cooling system return pipe, all hard to access. I expect all of these are pretty common access problems with 4 banger transverse mounted econobox engines. My older VW Rabbit however had this same transverse configuration, yet water pump, egr, & cooling system piping wasn’t as much of an access problem.

Unusual early 90’s Corolla water pump replacement procedures are shown on several u-tube vdos if you’re looking for some comedy. One shows it being done w/the engine out , another they remove the intake manifold, and a third they cut away portions of the inner fender … lol …

For newer cars with an engine compartment that jammed pack full of stuff, I’d be tempted to take the car out of service occasionally, and just remove the engine/ and do everything needed for the engine compartment at once.

Brake lines, fuel lines and brake hoses on my Chevy truck. All installed before body marriage so they are clipped to things not seen by humans since the assembly plant.

When the brake pipes rotted out, I cut what I could see out and fished the new lines like wires in a finished wall. I zip tied them to the old lines. Doing it “right” would have required dropping the fuel tank.

Same for the fuel lines with the same rot problem. They were clipped to the top of the transmission on their way the the engine. Can’t see 'em, can’t touch 'em can’t reach 'em. Cut them and again zip tie the old lines.

One brake hose at the center of the rear axle… the uper connection is clipped and nearly blind. Very hard to get the clip out and frustratingly insane trying to screw the brake pipe into the new brake hose.

I understand why they were done that way but it makes service hard.


Good & practical idea. For hard to remove wires & tubes, just leaving the old ones in place and zip-tying new to old for support makes a lot of sense for a diy’er. The same idea could presumably used for the rear pumpkin brake union gadget, just install a new one , leave the old one in place.

Thought of another frustration on my Ford truck. Two gas tanks, has a complex gasoline valve to switch between the two tanks and the two return lines. Eventually starts to leak. That valve is situated where it is hard to replace , worse, replacement part is not available. My current solution is to bypass the valve entirely and only use one tank.

The bottom line seems to be this . . .

I and the other professional wrenches on this forum definitely have job security :smile_cat:


Just had my son finish up a long job (waiting on parts), the 04 Infinity I35 (3.5L) w/121K miles, had new plugs installed at 105ishK miles… Kicked out a P0303, (right side back), of course the upper plenum 100% covers the right bank (135) plugs/coils… If it had been a Left bank side, I would have only replaced the one coil and plug… But nooo it had to be the right bank, so I ordered all 6 OEM plugs and coils and plenum gasket… RockAuto saved me a lot of money… Well after the parts got here my son started tear down, hey dad the #1 spark plug tube is full of oil, but the other 5 are dry… OK, I will order some valve cover gaskets real quick and you can do them, wait, crap, stupid Nissan’s and their non serviceable tube seals, OK have to buy new valve cover(s)… RA again saved me a ton of money but now we play the 2nd waiting game… Covers came in and son comes up and hands me this odd looking hard as a rock and of course cracked on both ends hose of some kind… It takes awhile to figure out it is one of the PVC hoses that connect to both valve covers (3 total)… Finally find it (OEM Nissan part) on Parts Geek, stupid high delivery for as long as it took to get to me, so another long waiting game… uggg…

WhyTH did Nissan start doing the, have to replace the normally expensive valve cover when it could be like most and older Nissans and just used a replicable tube seals, I can better understand hard to get to clips and such, but why mess with a tube seal design that still leaks even though it is a “better design”… Stupid design engineers that have never had to work on anything…

I have always said, you should HAVE to be a mechanical engineer before ever being allowed to design anything other than a coffee mug… :man_facepalming:

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Agree 100% :grinning:


I recall Taurus/Sable power steering hoses that were insanely crazy to replace and those were popular vehicles. My local parts store would cut the long metal section and install a threaded connector for $10 making life good. The local Ford dealer got in on the deal and the price rose considerably.

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Had an early 70s Pinto, timing belt broke, took 15 minutes to replace. 91 Mustang, 4 cylinder same 2300CC block as the Pinto with a different head, too much stuff in the way, ended up taking it to a shop for the belt.
92 Taurus, heater hose failed, decide to replace all such hoses. Most hoses were molded, besides the dealer, had to go to two different suppliers to locate all needed hoses. OEM hoses were attached with none removable clamps, had to be cut off with a rotary tool.
Much rather work on a pre ‘73 car! Except my ‘59 Pontiac that had hoses from water pump to head nearly impossible to replace without removing the water pump. BTW, mine had the single two BBL.

We owned a Ford Taurus SHO for several years. This was equipped with a DOHC 3 liter 7000 rpm screamer of an engine. The engine bay was stuffed so tightly, a glass of water poured over it would run off the fenders rather than go though! (slight exaggeration)

I thought I’d change the spark plugs when it hit 50K. Not only could I not even remove the spark plug wires from the front plugs… you had to remove the intake manifold to access the rear 3 plugs.

Then the crank position sensor failed. Had no time to mess with it so I sent it to a dealer. The estimate was reasonable so I approved it. Three days later I got the car back. I think the estimate was for the pushrod V6, not the DOHC motor because they tried to charge me a huge fee to change the 2 serpentine belts while it was apart. I refused. When I got it home, I changed them myself… took almost 2 hours. EVERYthing was in the way. The belts had to be twisted to pass the frame rail and them back to slip over the pulleys.

Then I read the 90K service requirement. The valve clearances needed to be checked which required a LOT of parts be removed to access the tappets. I sold the car at 80K as did a lot of owners when they got estimates ($1850 in 1999) for a car barely worth $4500. And at 90K the clutch wasn’t far behind.


I’ve had this for a couple years and still haven’t found the spark plugs :thinking:


I’ll go further. I think you should have to work in all facets of the technical end of the business before you’re elevated to design engineer in any function. Do a stint on the line assembling product. Then do production testing and warranty work. Spend some time as a manufacturing engineer. Handle application engineering and questions from customers. Then you can sit in a {insert technical function} design engineering seat…


I have worked on some pains, mainly Chrysler products, where parts would be easy to change with the engine OUTSIDE of the car but not once it is installed. The car was made to be easy to assemble but not repair. Thermostats come to mind.


Definitely. You should send those guys a box of donuts :wink:

Speaking of job security-
There was an old joke about software engineering. There’s been quite a few ill-conceived attempts to measure software engineering productivity and compensate accordingly. Hint: it’s incredibly difficult in any quantitative or meaningful way…The joke revolved around a simple approach that counted the number of lines written in a given period of time. In reality, this actually encourages and rewards sloppy coding and overly complex code.

One software engineer to another: Whatchadoin? I’m writing myself a minivan…


Yeah I suspect the main concern is manufacturing efficiency. I’ve never had the option of touring a plant since I lost my chance in sixth grade, but I have looked at quite a few you tube assembly plant. Amazing how easy everything is to get at before it’s all put together. Reverse the steps as they say. Most people don’t have the equipment to raise the body though.

No truer statement. what with newer cars being a computer network on wheels, and the intro all the new design mechanicals like variable valve timing, direct injection, turbo’s, high school students – esp those who have a desire to work in a technology related field — should definitely consider the field for their career choice. IMO the car diagnosis & repair field has much better job security than the computer software field.

Unfortunately, it’s still somewhat unregulated and there’s substantial turnover, last time I looked

I expect the Nissan mechanical engineers are as expert as any of the other car companies. And they would have been happy to design a more serviceable config/ The problem is their bean counters insisted on a cost comparison. The manufacturers believe almost every penny for parts and labor to make the car comes at the expense of their bottom line. Nissan management is probably especially cost-to-build sensitive, b/c they tend to focus on selling to the most price conscious new car buyers. I’ve seen questionable design decisions made in the electronics field to save as little as $15 on product that will sell for over $100K. The burden is on the new car purchaser to compare the cost of typical repairs, car to car, before deciding which one to buy.