every morning lately start up the 98 tahoe and theres a valve (lifter) taping (loudly) till oil presure builds up, usually minute or two then alls quiet, i dont really want to go into the motor after this lifter, could i just go to different oil? i think it calls for 5w-30 what would 10w-30 or 20w-50 or even 30 wt do if any thing appreciate any help:yes:
thx scott

I would install a pint of Marvel Mystery Oil myself along with an oil/filter change. This worked for me on a 66 engine I put in my 65 Ford Wagon.

what motor?

Scot,
Oil pressure should be there within about 10 seconds of starting the engine. My 99 jumps right up to 50 lbs almost as soon as it starts, thats with 5w30 Mobil 1. If it really is a lifter problem, I dont think that 10w30 is going to make any difference. How many miles on the engine ? What type of oil filter ? I have seen some off brand filters cause the same thing except its usually more than 1 lifter. I would change the oil and filter using an AC Delco filter, then see what happens.

Also, are you sure its not piston slap, which those engines are sort of known for ?

Wasnt the LS based motor the engines that had the piston slap? I dont recall hearing anything related to the 5.7 engine. Which is what is most likely in the 98 Tahoe. Thats the only engine I know of that came in those until the body style change. My 97 has it.

it is a 350, i dont think its piston slap, the oil presure on start up is about 40 psi till i rev it a little then it hits up to 60 or so maybe more with a loud tapping at half engine speed then after a minute starts getting quiet then quieter then gone 100,000 miles on the motor any thoughts i dont remember what type of filter im going to change the oil and filter again to see if that helps
thx scott

Chris,
The 5.7's certainly have the problem too :( My 99 is starting to get a little noisy at 85k or so. I really notice it because I keep it in the garage and you can really hear it inside.

Scott,
If yours has not had intake gaskets done yet, it is due ... you can swap the lifter while the intake is off :) Just have to figure out which one it is.

well i did the intake gaskets last year:sad:(what a pain) they leaked coolant out the rear down the bell housing, i changed the oil and filter(ac delco) last night, cut the filter apart and it was gumed up, this morning same noise a little quieter so i guess ill driver a while see if it goes away or back in ill hafta go, i already know which lifter it is, i had tried to adjust it out a couple of weeks ago:( any thought to changing all the lifters or just the one causing the trouble?
thx scott

I was thinking 5.7 and 7.4's.

Have a similar noise and have had since it had 20K. Now with 130K the noise comes and goes. I think the noise is much lower though. Piston or crank. Have known of soft cranks in these years and earlier. My oil pressure never drops below 40. Since hitting 100k I do run Lucus through it once a year.

Also did intake last year for same issue. Keep that coolant changed regardless of what the advertised life span is!

Also, are you sure its not piston slap, which those engines are sort of known for ?

That's my guess...