valve tapping when engine is cold

I am hearing a tapping sound in the engine(valves tapping?) when the engine is cold. After running for 1/2 hour or so, the tapping stops.
Well, it doesn't stop completely but it's not as loud.
A mechanic told me to use engine flush the next time I change the oil.
Will this solve the problem?

Also, when the ac compressor cycles on, I hear a "rattling" sound.
What could be causing this?

Steve M.

I just went throught the ratteling in the compressor, it could be low on a/c oil. If yours is R134, try adding 2ounces of oil. you can buy it at any parts store. If that doesent stop the rattle, the compressor may be shot. I was filling mine up about every 4-6 weeks because it had a very slow leak, probably in the evaporater. The commpressor final froze up on me. I replaced it with a used one from the junk yard and so far its been running fine

valves tapping means need to have valve adjustment, this day toyota using the valve shim and is not too expensive to repair if you know how. Engine flush will not do the job, it is common problems for toyota if you have high mileage and lack of change oil.

Not all rattling comes the valve. My 92 Corolla had a rattling that sounded identical to valves when the engine was cold, it turned out to be the bearings in the belt idler. If applicable , carefully squirt some WD40 when you hear the noise around this area to locate noise source if applicable.

Valves can make noise when you start up, because oil has to work its way up the oil galleries and whatnot to get to the valves. It takes longer depending on what kind of oil filter you use. The best oil filters are factory one and the Fram X2. they retain the oil when the car shuts off. other oil filters empty when the car is shut off. Meaning, they have to fill up before the oil gets anywhere above the block. YOu can spend 10 bucks either way and get a good oil filter. Also, those two types tend to last longer, upwards of 5- 7500 miles. You could always just change the oil and leave the filter for two changes. Something to thnk about.

Also on oil, toyota has a problem with oil sludging. If you notice your not changine out as much oil as your are putting in, take off your valve cover. Sometimes its all sludged under it. Pennzoil is also recycled oil and will definatly sludge, so dont buy that crap.

True your valves could probably use a shim or an adjustment.