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Noise after oil change

I recently changed the oil in my '01 Focus when I noticed that it was pretty low. After I was done I started my car and heard a sound that was brand new. The engine was making this low noise, almost like a diesel truck, a sort of knocking. A keep a good eye (or ear) on my engine sounds and I’m positive this wasn’t occurring before the change. Once I heard this I kept it parked until I could get it to a shop. They checked it out and said they couldn’t find a problem. They went ahead and change the timing belt but the noise persists. I know the oil change could be completely unrelated but it seemed odd. Any ideas as well estimates on repair would be much appreciated.

Also, the engine cap said that it required 5W-20. But I looked at a repair manual for that year and engine and it said to use 5W-30, so that’s what I used. I don’t know if that makes a difference.

Who 's repair manual was it? Ford or someone else?

This time of year 5W30 should be fine for most cars, but come winter you might want 5W20 IF that is what is currently recommended for your engine. Sometimes a manufacturer will change the recommended oil after the fact. I suggest double checking with Ford to see what their current recommendation is.

I also suggest you don’t get overly worried about this.

Your car requires 5W-20. Whatever manual you looked at was wrong.

Explain what “pretty low” means as far as your pre-change oil level goes. How low? Did the oil light come on?

Is it still making this knocking noise? Immediately after refilling the oil you can sometimes briefly (few seconds) get some knock noises until the new oil makes its way throughout the engine.

I’m also curious about this: “They went ahead and change the timing belt but the noise persists.” How did a timing belt get into the picture? What does that have to do with anything? Was this your original belt? If so, then a picture starts to take shape - you were low on oil AND probably a couple years overdue for a timing belt. So maybe you haven’t been careful about maintaining the car? If so, then you could be anywhere with it by now.

The manual was a Haynes complete teardown and rebuild manual. I’ve only had the car for a year and the owners manual did not come with it. I looked at the oil level about a week ago and it was at normal level. Then on Saturday I went ahead and changed it since I’m getting ready to go back to school and it had been about 3 months since I last changed the oil. That is when I check the level and noticed it was below the minimum line, but no oil light ever came on. I checked the bottom of the vehicle for signs of leaks but didn’t notice anything. The knocking noise continued and was noticeable when I took the car to be looked at on Tuesday. I told the owner that I needed that fixed and that the car was having a problem shaking when at idle, so I guess that is why he replaced the timing belt. I drove the car around a bit yesterday and the knocking sound was still coming from it although the car’s performance didn’t seem to be affected.

Given that this sounds like a new and fairly sudden oil loss (is it?) AND the noise, I would have someone check the compression on the engine and look for serious problems. I would not have the same shop do it because any shop that wants to change a timing belt because of a rough idle probably shouldn’t be trusted.

It is quite possible that you were due for a timing belt - is that why it was changed? Was anything else done, like spark plugs, wires? You know - things likely to produce a rough idle?

In any case, I’d get a second opinion on the condition of the engine. I doubt that the knocking is just about 5-30 rather than 5-20

No new wires or spark plugs were changed at that point. I changed them about 5 months ago. I also had vacuum lines nd hoses replaced at the end of June. Oddly enough, since the timing belt was changed I had no problems with the vibration at idle when I drove it around yesterday.

Did they maybe say that the timing belt jumped a tooth? That would be uncommon but certainly would give a rough idle.

Josh, It’s OK To Use 5W-20. Ford Included Your Car (2000 - 2002 Focus 2.0L) In A Technical Service Bulletin Application List, Recommending It For “Improved Fuel Economy” .