The 350 V8 in my '98 GMC 1500 ticks when it is started up. It runs OK when it has been going for a few minutes at higher RPM, but the tick can return after idling. It had sat for about 2 years prior to my purchasing it, and it did not start the ticking until I had driven it a few times. I put on a new distributor cap, rotor, plugs, and plug wires, but I suspect a lifter issue.
I seafoamed the engine prior to changing the oil. I put a 1/2 bottle in the oil and about 1/3 bottle in the brake booster line. That made no difference. I have heard that I can run 4 quarts of oil and 1 quart of high-detergent ATF to clean out gunk that can accumulate in the pinholes of the lifters. Since I am not that familiar with pushrod engines, I would like a 2nd (or 3rd, or 6th) opinion. What do you all think?
GM lifters are known to clack when thier cold but should go away once its warmed. if its not the lifter may be collapsed (seals in it are gone) which means it needs a new one. you can try the other remedies but in the end i think replacement is due.
They were ticking HARD when the engine was cold, and a bit when it was warm. It ran OK the first few times I started it, so I didn't think it was a big mechanical problem. The truck had sat for a couple of years when I bought it, only accumulating about 400 miles in the past 2 years. Of course, the oil was not changed in that amount of time.
I put seafoam into the crankcase and sucked some into the brake booster line, and that did not cure the lifter ills. After that, I drained out 1 1/2 quarts of oil and put in 1/2 quart of Lucas oil treatment and 1 quart of automatic transmission fluid. After 3 cold starts with this mix (about 10 miles total), the lifter ticking was completely gone. No sound at all.
My friend and I just removed the intake manifold and valve covers so we can replace the intake manifold gasket. That engine is clean inside! No sludge. The valvetrain looks great. We have a bit of aluminum dust in there from when we ground a notch into the A/C bracket so we can remove the front intake manifold bolt. We vacuumed all of it out that we can see, but I will change the oil and filter again just to be safe. If the lifter ticks start back up again, I will run the same mix until the next oil change.
Speaking of 98 GMC intake manifold gaskets... The body shop called, said my truck was ready, but its running like its got a bad vacuum leak. They traced it to a bad intake manifold gasket, so they're changing that out for me. Hopefully I'll have my truck back soon.
While I was working this week, my friend Greg put the engine back together. We must have scrubbed off the mark on the distributor. Now we need to reset the timing. That will be an absolute pain in the butt.