damned lifters

[Chris2020]

OK no crisis yet afaict. 1998 GP GT. This car has a history but I had always assumed the mighty 3800 would be my last worry. Waiting for my Big Macs the other day that hideous noise reared it's head. Drove it home, heard it briefly when I lifted the hood. It seemed to go away when I topped off the oil, ~ 1/2 quart. I also poured ~1/2 coffee cup of MM oil in the crankcase. Most of the driving since has been 65mph+. In the early morning hours, when my vehicle info center is barely viewable, backlight? blown, it says my oil life is expended, and "low" displayed at the top. I changed the oil about 1500 miles ago. No low oil pressure light on, and bulb works. No unusual heating problems, but it did seem to get up to temperature fairly quickly this afternoon. Haven't discerned any more lifter noise, but I don't want to push it by letting it idle.

 In the absence of anymore lifter noise, or other indicators, should I be worried? Should I change the oil with say 10w40? Or just change it right away with 10w30?

 

Oil pump replacement on these are comparatively easy, right? I guess it's just wait and see for now. Or are there other checks and or maintenance I can perform? Just under 150k on motor.

 

 

[vipmiller803]

How would changing the oil pump do anything for your lifters again? Remember oil pumps don't decide oil pressure, it's your engine's tolerances that do.

The noise went away when you topped off the oil? Or when you added the MM oil? I've seen atf and/or MM oil clear up lifter problems. How long have you had the car? What's the oil change history like on it? You might be better off doing a set of lifters.

[Chris2020]

Well this much I know, if you change lifters you also must change the can. As thrilling as all that sounds I think my efforts are better expended otherwise.

I've been changing the oils faithfully, Castrol/Pennzoil high mileage. Got the car about ~126k. It's a beater if only in appearance. I just bought all around struts so I guess I'm committed. It hasn't had much highway driving since I got it, and 20 miles a day, each way, 2 days a week, isn't a lot. But maybe I loosened some crud? The car performed flawlessly yesterday and today, so for now I guess everything is cool.
It needs a tuneup severely. I assume. Will attempt to get that done this week. Had the car over 3 years. I'd like to make the best of it. And I'm no stranger to the list, lost my old password.

[Chris2020]

1 hour ago, vipmiller803 said:

The noise went away when you topped off the oil? Or when you added the MM oil?

I assume when I added the oil. But maybe it just went away.

Personally I would never replace a quart of oil with MM oil. I ruined an engine with a witches brew of replacements, and granted I did it stupid. But forevermore I'm going light on extraneous solvents.

And if you yank the filler tube, there is a lot of varnish visible. I'm going to be changing the oil every 2k for a while.

 

 

Edited May 19, 2019 by Chris2020

[Schurkey]

On 5/18/2019 at 5:51 PM, Chris2020 said:

OK no crisis yet afaict. 1998 GP GT...  ...mighty 3800

my oil life is expended, and "low" displayed at the top. I changed the oil about 1500 miles ago

Did you reset the oil life monitor when the oil was changed?  I'd expect 6K--12K oil life depending on how the vehicle is run.

Adding less than a quart of oil did not quiet the lifters.  Adding three quarts of oil might.

On 5/19/2019 at 2:05 PM, vipmiller803 said:

Remember oil pumps don't decide oil pressure, it's your engine's tolerances that do.

Not really.  The word you're looking for is "clearances", not "tolerances".

A high-volume oil pump certainly can boost pressure, as can a non-worn-out pump.  Does this engine still use the stupid aluminum-housing oil pump built into the front cover, or had that gone away by '98?  The Buick design oil-pump-in-the-front-cover was a disaster.

On 5/19/2019 at 3:31 PM, Chris2020 said:

 if you change lifters you also must change the can.

1.  These are roller lifters...right?  Why would you "have" to change the cam?  For that matter, guys got by with changing flat-tappet lifters on used cams for decades--assuming the cam was used but not worn-out.  A lot of this has to do with valve spring pressure--what can work for stock valve springs may not work for 9000-RPM, high-lift valve springs.

2.  Take the lifters apart out and apart one-at-a-time and clean them.   Hydraulic lifters are miniature oil filters.  The oil inlet passage is fairly huge, but the oil outlet is microscopic.  Crap gets in, can't get back out.  Lifter fills up with sludge.

Edited May 21, 2019 by Schurkey