90 olds 98 3.8l

[Guest gsbuick65]

my wifes olds has 2 problems, 1 is it has a 'rattle' towards the rear of motor near the tranny, sounds like in the center of motor. I thought it was tranny chain had tranny rebuilt, no change. its more noticable after you rev up the motor. its sounds like thin metal rattling. 2 its shows quad 1,2,3 failure on my turbolink, is that the coil?

p.s. it has the original timing chain with 220,000 miles

[Reatta Man]

If it's in the middle of the engine, it really sounds like a worn bearing. If it has an oil pressure gauge, and the pressure is low or almost non-existent at idle, this would tend to confirm a worn and rattling main bearing.

Has it been on regular oil or synthetic oil for most of the 220,000 miles? If it has been on regular oil, you are probably looking at a rebuild soon. If it has been on synthetic, you may be able to drop the pan, clean the gunk out of the bottom, change the main bearings (if there is no scarring or deep grooves in the crankshaft) and go on.

Good luck.

Joe

[JohnD1956]

My son's 89 Lesabre t type has this rattle as well. The local Buick dealer diagnosed this as a bad bearing in the rear of the counterbalance shaft. We never did get it fixed and the car is still going with 180K on it.

[Guest gsbuick65]

have been running reg. oil 5w30, going about 4000 miles between oil changes, she drive this car faster than I can change the oil. should I put a mech. oil gauge on it?

[Reatta Man]

I think a mechanical or electronic gauge that gives you a continuous oil pressure reading would be a good idea.

As for the dealer's diagnosis of the other engine's noise being a balance shaft bearing, that sounds unusual. The balance shaft is not carrying anywhere near the continuous load and regular shock of a compression stroke the way the crankshaft does whenever the engine is running.

The only way I can think of that the dealer can diagnose this is if he has had other 3.8 engines making the same noise and it consistently turned out to be the bearing on the balance shaft. It certainly could be that bearing, but I would suspect the main bearings on the crankshaft before I would think of the balance shaft.

As the medical schools tell their students, "when you hear hoofs, think horses and not zebras." That means alwasy consider the more likely solution first, rather than the obscure, less likely possibility.

One other consideration--if the noise is only noticable on the initial cold startup in the morning, then you may have more of an oil starvation problem. If the noise is far worse on startup, I would go up one grade of oil, to a 10W30, 10W40 or 15W40. In the summer, you could even go up to a 20W50 and see if the noise goes away or is much less severe.

Also, DO NOT use Fram filters on a worn engine. For that matter, I don't recommend them on any engine, but especially on one where the clearances may be larger than factory spec. Go with a very good name brand, such as Wix, AC, NAPA or Mobil 1. Do NOT use any Fram oil filters, or any cheap store-brand filters on an older engine.

As for the computer code, I don't understand what quad 1,2,3 means. Usually older GM computers put out a two-digit code. It flashes 12 three times when you first go into diagnostic mode. That shows the computer is working. Then it flashes other two-digit codes, such as 23, 44 or 45. Once you get the proper code, you can cross reference what it means in the service manual. On some cars, such as the Reatta and Toronado, the computer uses an alpha and three-digit code, such as E123. Is this what your computer is giving you, or are they the simple two-digit codes?

Joe

[NTX5467]

You can probably get a brass t-fitting and tap into the oil galley where the factory sending unit is, then run the mechanical gauge from there--even if it's just temporarily to see what the oil pressure is and/or how it acts upon initial start-up and at various rpm levels.

On the earlier non-balance-shafter 3.8L V-6s, if they did not see reasonably regular maintenance they'd get a main knock in them--the center main bearing. From what my machine shop associate told me, the main oil galleys were cast in and then drilled. In other engines, they are drilled with one long drill bit, front to back, but on the 3.8L Buicks, the oil galley is a two-sized affair where there are front sections and rear sections, with a smaller section in the middle. One bearing, less oil, smaller cross section in the galley? Sounds reasonable, but with poor maintenance, the center section gets smaller with "accumulations" so the center bearing is somewhat "starved" compared to the other ones, even with good oil pressure in the system. Pressure but not enough flow, it would seem.

Not sure what the aftermarket shops might see, but I suspect that very few GM dealerships stock anything for a 3.8L Buick V-6 other than some gaskets. HIGHLY reliable engine, especially if it's taken care of. Not sure about the balance shaft bearings, though, that's a "new one".

Do you hear it with the sight shield on the engine or off? Sometimes, it seems those things are on there to dampen the sound of the injectors doing their thing.

I concur regarding Fram filters. Fram is a very old name in the filter business, but when it became part of a big conglomerate in the '70s, things seemed to go downhill from there, construction wise. They might still "meet of exceed factory specs", but that does not mean they are built as well as an OEM brand filter. Wix, by observation, used to be a low-line filter, but when Dana Spicer bought them, that changed big time. In many respects, with OEM brand filters being so available these days, there's really no reason to buy an inexpensive filter unless that's all you can afford.

I've used ACDelco oil filters on my GM engines and have had no problems, even well past 300,000 miles. Even the current DuraGuard filter media in them has smaller micron filtering specs than what they did in the early 1980s.

If the motor's still running reliably, with no metal particles in the oil (maybe one of the GM magnetic drain plugs might be put into servivce?), then you might go ahead and run the engine a while longer. But also starting to save some money for possible future repairs or down payments.

Sometimes using a thicker oil might make some of the noises lessen, just don't go too thick. Sometimes changing from regular to blended synthetic or to full synthetic might have an affect on cold start issues as the synthetic will typically flow easier and sooner than a straight petroleum base oil. For general principles, you might do the next oil change with the same brand oil you've been using, but use 10W40 weight oil. The "10W" spec is for zero degrees F, while the "40" is for "operating temperature". So, at ambient 70 degree F temps, it would not be fully at "10W" but probably more like "20". But then the same would be true with the 5W30 too, for when the engine is first started, yet it would get thicker when the temperatures rose. Might take some experimentation to find what will successfully diminish the noise you're hearing, provided it's related to clearances somewhere in the engine.

You might also consider getting one of the stethoscopes at the auto supply tool rack. Or a long socket extension or even a broom handle can work too, but you won't have the ear pieces to deal with as you'll have to put your ear to the end of the "rod". Put the probe/socket/handle on various parts of the engine with it running and see where you put it that the noise you're concerned with is loudest. Then you can go from there. You'll probably hear LOTS of noises in there, but concentrate on the one you're concerned with. Be carefull, too, to keep any probes/rods AWAY from external moving parts (i.e., belts, pulleys, linkages)! If you don't desire to do this yourself, you probably can find a mechanic somewhere that can do it and then let you hear what he finds out. Could also be that the dealership mechanics know what they've talking about too.

Enjoy!

NTX5467

[Reatta Man]

NTX,

I noticed you work in the parts biz at a GM dealer. When the dealer swaps out a broken 3.8, do you ever see the reason listed in the paperwork for the swap?

Was just wondering if you have heard of this balance shaft bearing diagnosis before. It's a new one on me.

Joe