Any suggestions?

The same spark plug #3 misfire showed up yet again after having the car repaired a month ago. The mechanic is at a lost for why the issue keeps occurring. So far, here's what the mechanic shop did.

1. Replaced all ignition coils
2. Replaced spark plugs
3. Used a scope to look for cracks
4. Checked ignition coil harness for degradation
5. Compression test (a few years ago when issue started) Passed
6. Leak Down test - Passed (a few years ago)

Mechanic suggested that he would add injectors if the problem kept occurring

 

did you try spraying some carb cleaner around the injector (to test the seal) and the intake runner (not sure if its plastic like VWs which can crack). You can check for an injector cleaning service - they use an ultrasound cleaner (like a jewelry cleaner) to clean the nozzles and match flow. pretty rare for an injector to totally fail. Also test for fuel pressure - low pressure can cause a misfire CEL (saw this on our Gen 1 when the FPR failed).

 

Thanks. I'll inform the Volvo mechanic. Each of the two lead mechanics recommended a different approach, even after discussing it with each other.

Mechanic #1 (older owner has 20+ years as a Volvo mechanic): Put an injector in for any future misfires

Mechanic #2 (younger owner): Out of ideas and suggested taking the vehicle to a Volvo Dealership's mechanic who may have more advanced tools and know-how. He also stated that I should consider buying a reliable Toyota and saving money, because the current Volvo S40 will "nickle & dime" on repair costs ($1500 - $2000 a year).

My current position: Keep the S40 running as long as feasible on an annual mechanic budget around $1200 while also identifying the next purchase, if required. I do like how the S40 drives otherwise. Plus, stick shifts get rarer each year in newer cars.

Question: Do you know of any highly-skilled Volvo mechanic near or in Pennsylvania who might have insight and the ability to find a good fix?

 

Well I assume its a 2,4 volvo S40 non turbo , not sure what you have spent so far on an old car , but looking at the state of the alternator , must have a fair bit corrosion on many parts ,suspension ,etc
The S40 was not volvos best cars its a focus ford and have many issues , if you cant fix yourself its a money pit
You use it one day a week so get rid of it

 

The mechanic placed a boroscope in and left the car with pressure overnight and detected a head gasket issue after seeing a small amount of coolant later (approx. teaspoon).

He stated the vehicle can probably go another year with ease, based on only using it for grocery pickup once a week.

The other Volvo mechanic at the dealership who first identified the issue as a possible head gasket going bad also said I could probably drive the car indefinitely if I only used it for a grocery pickup once a week.

Other options: I'm leaning towards #2

1. Repair gasket (he also recommended that the car will continue to need other major repairs due to its age) - (i.e. possibly a clutch down the line)

2. Keep driving without repairing, while keeping an eye on engine coolant, which I usually do anyway.

 

Meanwhile, I'm wondering about the next step. Another mechanic who's unfamiliar with Volvos told me that the car might be a good candidate for Blue Devil sealer or some other product. I've only viewed the YouTube videos. At this point, I'm thinking it's worth a shot, although I'll probably get a local mechanic to do it, unless it's doable without a hassle. Otherwise, repairs sound like it's $4000-$8000 (without a guarantee something else will require fixing).

 

Sounds exactly like advice a mechanic first told me, too. I skipped doing that after reading up more about it. Presently, even with a few drops of fluid leaking from a gasket or somewhere, the S40 runs perfectly, except for the red triangular light on the dashboard indicating an engine service warning that the Volo dealership pulled codes for and said it indicated a misfire on #3 spark plug. In other words, the same issue from several years ago.

My 2007 S40 Energizer Bunny somehow keeps plugging on somehow. When running, it drives perfectly.

 

I'd probably discount the compression test since its three years old and the car ran fine following. Most likely that was done on a cold engine. If you really are curious about the fitness of the block, go out to Autozone and rent/borrow a compression test guage, find a Youtube vid for instructions and see what you get. While your doing that, you can also inspect/replace the plugs (go OEM - more expensive is not better for these cars) and inspect the wire harness to the coils.