Subarus noisy at over 45MPH

1998 Subaru Legacy L. Since I had my oil changed my Subaru is noisy at speeds above 45MPH. Engine seems to run hotter at 55 than at 45 but worrisome. The car doesn’t feel like it is shaking but the noise makes me think it is something vibrating. One time I pressed my hand on the interior light on the ceiling and one of the higher pitched noises stopped until I released my hand. I’ve check tire pressure, not sure what else it could be. I did turn off the heating fan because occasionally I get leaves stuck in that fan and it makes an irritating noise. While it is that time of year I don’t think that it is the issue. Normally when I am driving on a nicely paved highway it is pretty quiet. I am ready to take it into my mechanic to check for problems but I wanted to see if anyone here had any suggestions.

Is the check engine light on? If so, you can get that read at a chain auto parts store. Tell us what it is and maybe we can help you. Or you can just wait until you take it to the shop and they will tell you what it is.

You can check for leaves in the fan yourself if you like.

No engine check light. My Automatic has not detected any engine warnings.

Hmmm, I am going to check the oil level. Been meaning to do that.

That should have been done before you left the oil change place. Replace 'meaning to do that with a set schedule ’ . On this old of a vehicle I would say every Saturday before going anywhere.

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Hopefully, you will also check the trans fluid–if your Subaru has an automatic trans–and you should also check the final drive fluid. I say that because incompetent shops have been known to drain the trans fluid or the final drive fluid instead of the motor oil. The result is a dry trans or final drive, and an engine with twice as much oil as it should have, and that scenario is the formula for an imminent disaster.

Just looked, the oil might be on the low side but I cannot see the low and high markings on the oil measure. But there is a twist in the stick and the oil seems to go just above it, from the manual it looks like it should go hirer. I’ll have my mechanic check it. I don’t see any signs of an oil leak but I want him to check it out.

I’ve been using the same mechanic for around 20 years and they are highly recommended. Never had them make a stupid mistake. When I had a problem beyond them (rear differential or body work) they people they recommended did good work. They have also done the big work like changing timing belt and that nasty seal.

However, anyone can make a mistake.

Arè there any oil spots under the car or where you park?

No oil spots. I have a concrete driveway so any spots would be easy to find (as when I did have an oil leak 2 years ago).

Did they rotate your tires? Also the oil should not go past the twist near the bottom of the stick. Your oil maybe to high and hitting the crankshaft.

Pull the dipstick out and wipe it with a rag. You should be able to see the high and low marks clearly, then insert it and remove to determine the oil level.

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I had a similar problem misreading the dipstick on a new Subaru and overfilled it. the manual shows the two holes above the twist, But think there is another twist higher up. Just look for the two holes in the dipstick.

06%20PM

as another idea: check your receipt if they used a correct oil weight.
likely, later-90s Subaru was calling for 5W30 or 10W30, but newer ones require 5W20 or such.
Getting less viscous oil into the car calling for more oil viscosity can definitely make it work with more noise.

When I was 4 years old I looked forward to “helping” my Father check engine oil, tires, and radiator on our 1952 Chevrolet every Saturday. I still check engine oil weekly.

The timing of me noticing the noise and the oil change was a coincidence. I need the right rear ball baring joint replaced. I probably mangled the exact operation to be performed.

2 years ago my car was hit on the right side of the rear bumper. I needed the bumper replaced and some underlying supports, this is when I learned that Subaru still makes new parts for 20 year old cars. I had the bearing replaced 2 years ago, this time the entire joint. The mechanic says that after this repair I shouldn’t have a problem in another 2 years.

Thanks to everyone for their opinions thought it turned out not to be the oil or transmission fluid. So I won’t be asking opinions on the 2018 and 2019 Subarus this time. Bill, thanks for the diagram with the dip stick. Mine has the holes in your pictures, my manual show 2 etched in markers for for the high and low.

While besides the point I usually only drive the car on weekends, two 60 mile trips, mostly highway and then a little local driving. But I needed to take car of this now since I have lots of Thanksgiving related driving starting tomorrow evening.

Also they might retroactively recommend the presently recommended oil. That was the case with my 1999 Honda Civic. 5W30 in the owners manual - but a few years ago the Honda dealer showed me the newer chart, which said 5W20 for the current AND the older engines.