'91 Camry Engine Knock

My '91 Camry V6 runs well unless I have to let it sit for extended periods. If I go on a fishing trip for several days and leave it in the driveway, when I come back and start it up, it shudders for the first 10 seconds, then there’s valve clatter, then it smoothes out and it’s OK again.

I was gone last week (7 days) and started it up to move it out of the garage and now it’s added a loud knock to its symphony. There were about 4 good strong knocks, with the shuddering, then the valve clatter and finally it smoothed out.

I drove it to work this morning, 25 miles, and I’ve recently taken it on trips of 160 miles without any problems. It leaks oil around the valve covers but I keep the oil changed and refill when it gets to be a quart low. There is some smoke on start up, probably worn valve guide seals.

150,000 miles

Platinum plugs changed at 120,000

Oil and filter changed at 5,000 intervals

Gas mileage is good, averages 23-24 mpg

Oil usage is about 2 qts between changes

It’s old but dependable. If I had to guess I’d say that a cylinder was starved for oil but as long as I drive it at least every 3 or 4 days it runs just fine. It’s just the extended time that it doesn’t seem to like. Any ideas on what causes the knocking and shuddering?

The knocking and mechanical noise is your engine being starved for oil at startup. Probably the oil filter doesn’t have a good ‘anti-drainback’ valve. This is a small rubber flap that keeps oil from draining out of the filter. What you’re hearing is your engine not getting any oil pressure until the filter refills. You might try a different brand of filter. My car also is susceptible to this. Wix filters seem to have a pretty good valve in them and my car doesn’t do this hardly at all with a Wix filter on it.

I’ve had the car since buying it new. It’s always had the Toyota filter which I’m pretty sure has the check valve in it. The driveway is pretty steep, not sure if that has anything to do with it. I can understand valve clatter but the ‘knock knock knock’ has me worried now. I think the vibration is that it’s not hitting on all 6 cylinders but that would mean fouled plugs from burning oil and I don’t think I have that. I have the smoke only rarely and only on startup.

Try a different brand of oil filter and see if it helps. You can change the filter without changing the oil. Just top the oil off after changing it. If you do it yourself, you may want to partially fill the filter with oil before putting it on. This will help the engine get oil pressure sooner and reduce the amount you will have to top off.