my 98 volvo has fairly loud lifter noise that seems to come and go periodically and independant of any conditions that I am aware of. I check the oil almost weekly. Sometimes,the noise will start as I start the engine and stop mid way through the drive. Sometimes it won’t start until midway through the drive. Help.
Need more information to be sure. Lifter noise is almost always caused by lack of lubrication. This happens as the oil pressure falls. Oil pressure can be low in older engines due to wear opening up the oil passages letting more oil through the wear surfaces than when things are new. Sometimes when the engine is worn, the combination of engine heating up causing the passages to be bigger and oil thinning out due to warming up are enough to drop the oil pressure enough so the hydraulic lifters starve and start clicking. Some times you can clear thisup by trying a heavier weight oil. But I think you are looking at major engine repairs for the final fix.
Your motor is turbo charged and needs good oil changed every 5K miles to avoid sludge and varnish build up. My guess is you have a “sticky” lifter due to some “gunk” stuck to the lifter itself. Might not be anything you can do short of tearing down the motor and replacing the lifters.
Try a 5W-40 weight synthetic oil for the next 2 oil changes and see if the noise gets better.
Thanks a ton, guys. Do you think it matters at all that it comes and goes?