Oil leak, prob rear cyl bank '98 Riviera 3800 Series II, supercharged

The basics...1998 Rivera, 3800 Series II motor, supercharged, about 176,000 miles. I've noticed an oil leak that's getting worse and worse. Inspection from the top and bottom makes it difficult to pinpoint the leak due to obstructions (I miss my '59 Ford), but I can isolate it only as far as the rear bank of cylinders. Doesn't appear to be the oil pan, but leaking downward onto the pan and onto the ground. As you know, the supercharger and alternator with a sideways motor doesn't help finding exactly where it's coming from an easy job. I suppose a mechanics mirror might help, but if it's just the valve cover, what's the point...you're gonna fix it anyway. What I'm trying to find out is what parts I should buy up front to minimize downtime and any recommendations that when you get down that far, what should be replaced so you button the car up and not have to redo the job again for another 100,000 miles. I know plugs and wires…that’s the obvious one. What else, wise sages?

Now for the job itself. I know the alternator and engine hoist parts need to go. But the supercharger? Some nice write-ups on removing the snout or cone, but can the supercharger be more easily removed as a unit? If so, can anyone point me to a good video or write up with picture so I can follow along? I want to do the job right the first time, especially since “winter is coming”, and I’m a minor league mechanic but a major league part changer. I do this for knowledge’s sake, not the money (although it’s nice to feel you did just as good a job as the guy in Detroit). Not sure which tensioner needs rotation either, but I have a set of Riviera/Aurora manuals and can probably figure that out.

As for the parts list again. Best gaskets anyone? Original GM. Fel-Pro. Mann? What else? Anyway, your advice and wisdom is appreciated.

Oh. Last point. As I’m sure almost 100% of forum follower know, GM has had to participate in recalls on the 3800 Series II motors for a variety of cars because of oil leaks and fires, but the Riviera was NOT on the list. I reported my leaker to the NTSB (National Transportation Safety Board-I dislike too many acronyms) with pictures of the size of the leak, and of course, heard nothing. I’ve a mind today to call them and see if any plans are in the works to include the Riv’s in a recall about oil leaks and fires. Ya never know, and it can’t hurt.

Also alerted them to holes forming in gas tank filler pipes caused by wheel hop when you go over those speed bumps on roads and apartment complexes and the rotation of the rear tire wears a hole in the metal pipe. Good luck finding new, as GM discontinued the part. I’ve got my filler pipe duct taped up and it’s holding until a recently pulled unit from the junkyard gets it’s small pinhole leaks epoxyed up. Anyone throwing emissions codes might want to pull the driver’s side rear wheel and look at the filler pipe. Not a bad time to hit the rear grease fitting anyway.

Thanks in advance for looking, you comments, and any help you can add.

1) fix the valve covers, just replace the gaskets.

2) The oil pan might be an issue. If the car was ever jacked up with a floor jack under the oil pan, since the pan uses a crush gasket it will start to leak.

3) IIRC the Riviera didn't meet the guidelines for recalls, I think due to too few cars or some such. That said, if the apparent risk bothers you, replace the LIM gasket and nylon gas lines and that's about that. There are instructions on those changes elsewhere on this site.

4) you *could* get a new fuel filler neck. http://www.jlcautomotivewarehouse.com/ecommerce/jlcgm065-new-fuel-tank-filler-neck-95-98-buick-riviera-olds-alero

5) At this mileage to minimize downtime one thing that comes to mind: Check your brake lines and consider overhauling the brake system - replace all the flexible lines, replace hard lines with CuNiFer or coated lines, and overhaul or replace the MC and calipers.

The only 3800 "leak" recall right now is dumb IMO. All we do is replace the front Valve Cover and gasket, remove the Oil Filler extension, and throw away the engine cover. That's it. It never had anything to do with the rear Valve Cover or any other part of the engine leaking oil.

I think the main reason behind it all is that the majority of people don't take care of their cars, period. They allow the engine to spew for so long, that the sludge that builds up would eventually catch fire because of it. If you look at the recall, it's all Regals and Grand Prixs, not Park Avenues, Lesabres, or Rivs. I think it has more to do with the way those engines are mounted. The Rivs don't have the double dog-bone engine mountings to catch the leaking oil and let it puddle up.

The S/C doesn't have to come off for the rear VC to be serviced. I wouldn't even bother messing with it if you don't have to.

I do all my own oil work, Albert, so spillage isn't a problem. Dunno why it just looks like an awful project...the rear valve covers, given their proximity to the firewall, poor visibility. minimal hand clearance and the supercharger possibly in the way as yet another issue. But I imagine that once you start removing parts to gain some clearance, all shall be revealed. Time to pull the factory Riv/Aurora manual and see what it suggests. I'd like to think valve cover gaskets only, but will certainly look at replacing heater hoses as well. Like most things, can't hurt. And usually you don't screw up too many things with preventive maintenance. Thanks for your diligence in answering questions. Now it's time for me to review your posts on changing out all the bulbs on the HVAC unit so I can reinstall that. If you run across a thread on removing the supercharger as a unit (I've failed to find it...but then again, I failed to find the filler neck that I have duct taped, and you did in another post), please feel free to point me in the right direction. Many thanks. Christen

The S/C is actually very easy to remove. I don't recommend it unless it's absolutely necessary though. You'll end up replacing more things than needed if you're just trying to gain some arm/hand clearance. The rear VC can be removed/replaced without removing the S/C.

Below is for removing the S/C (without pictures).

Removal Procedure
Caution: Remove the fuel tank cap and relieve the fuel system pressure before servicing the fuel system in order to reduce the risk of personal injury. After you relieve the fuel system pressure, a small amount of fuel may be released when servicing the fuel lines, the fuel injection pump, or the connections. In order to reduce the risk of personal injury, cover the fuel system components with a shop towel before disconnection. This will catch any fuel that may leak out. Place the towel in an approved container when the disconnection is complete.

Caution: Refer to Battery Disconnect Caution in Cautions and Notices.

 1. Disconnect the negative battery cable.
 2. Remove the engine cover. Refer to Fuel Injector Sight Shield Replacement.
 3. Depressurize the fuel system. Refer to Fuel Pressure Relief in Engine Controls.
 4. Remove the supercharger belt. Refer to Drive Belt Replacement.
 5. Disconnect the right side spark plug wires from the ignition module and set aside.
 6. Remove the generator brace L67. Refer to Generator Replacement in Engine Electrical.
 7. Disconnect the electrical connectors from the fuel injectors.
 8. Remove the MAP sensor bracket.
 9. Remove the fuel rail mounting bolts and the fuel rail with the injectors.
10. Remove the boost control solenoid.
11. Remove the throttle body nuts.
12. Remove the supercharger.
13. Clean the intake manifold and the supercharger mating surfaces.

17 lb.ft on the S/C bolts when you put it back on.

You're welcome, Christen.

Probably the first thing to do is cover the electrical items (the connectors and the alternator) with aluminum foil and clean the engine/engine compartment.

Since you have the FSM, the PM is generally as outlined in the mileage/maintenance guide in Book 1. Thinking back over the years, only exceptions I can think of are:

1) to replace the transmission fluid with Dex VI if you've not already: I was told that GM is no longer policing the Dex III standard, if that's the case then a drain/fill with Dex III might not get much. And even in the "old days" for me Dex III was only good for 40K miles or so before it noticeably changed color. (time to change it when it does). Dex VI lasts **much** longer. Since I turned 150,000 miles I've changed it every 50-60K. Which is probably too soon. Then again my transmission has run 200K+ miles after a local shop overhauled it at about 98K miles... Give you a hint: they installed Raybestos Blue clutches in the ol' daily driver... we may never have to talk to (talk to = replace) that clutch pack ever again...

2) The bit with the heater and radiator hoses is that they are a pain to remove. You will want a clamp removal tool for the job. I bought one because I could not reach one of the clamps with pliers; it saved so much time and hassle, why would anyone use pliers? Do you have to replace them? Maybe not; for quite some time, since the mid 80s I think, those hoses have been made of synthetic rubber such that if you do regular coolant maintenance and keep them clean they will last a very, very long time. That said, you said PM so for PM to make sure you'd want to install good hoses and then as long as you keep the engine bay clean and coolant maintained, if your experience is like mine you will probably not have to talk to the hoses ever again.

3) You can screw up PM by replacing things with inferior parts. For instance on high-line Fords the sealed wheel bearing units are engineered for life-of-car, most replacement grade units are *not* so you don't replace those things unless or until they growl a little. Ever. And when you do you are probably getting the SKF, which costs much more than the "economy" ones or even the Timkens.

4) if you've never, change your supercharger oil.

5 and last) What you might want to do is work with the moderator of this forum to find and make up an index of all the PM items (there are many) and put it as a post in Write-Ups (see https://rivperformance.editboard.com/t6744-riviera-faq-write-ups-listings#15504). Us re-posting the good info there is kind of a waste; a post with the FSM maintenance schedule and pointers to the writeups that cover the tricky parts would be a way for you to contribute.

They don't make the "Blue Plate" Raybestos specials anymore for the 4T65E. Just FYI.

Good morning everyone. Reason I asked is you (AlbertJ) and Abaddon are frequent posters and obviously knowledgeable, so tricks and tips picked up from you guys is helpful to me...and maybe even a wider audience who don't ask the question (but wish they did). I spend a lot of time looking over the forum in the evenings and have gained a lot of knowledge, esp on the HVAC posts. Now I've gotta look over the T1-1/4 vs T1-3/4 bulbs, but that's not an appropriate topic for this thread, as we'll keep it to the 3800 Series II motor. One thing for Abaddon...what do you mean by <> Does that mean you might wind up breaking or destroying things, or you just get part happy and figure..."well, I've gone this far...might as well replace this, then this, and why not that". Just want to do it once and be done. As for Supercharger oil, your preferred source...dealership or alternate? I'll take that tip about the transmission and change gasket and filters, as I'll have to check Rock Auto for a set. Didn't even know they make a Dexron VI. Figured they stopped at Dexron III or maybe IV, if that was made. I gotta pay more attention to fluids.

I was just talking about vacuum lines, vacuum tees, things of that nature. Something little like that always tends to break. Or even better, the Injectors don't want to come out of the rail or the lower intake and you end up ripping an O-ring. Just little stuff on an old car.

I don't see ZZP listing an S/C oil any longer, but the GM oil is PN 12345982 (I'm looking at a bottle now). The GM stuff is all I've ever used.

Dexron VI is used in the newer trannies, and now all of their hydraulic steering systems (excluding HD recirculating ball gears). We still use DexIII in all the "old" transmissions.
If you're thinking about switching to Dex VI, you absolutely CANNOT mix the 2 fluids. They aren't compatible with each other. You would have to get a trans flush with a machine to make sure that ALL the old DexIII gets out, including the Torque Converter (which is what a flush machine will do).

Abaddon wrote:

I was just talking about vacuum lines, vacuum tees, things of that nature. Something little like that always tends to break. Or even better, the Injectors don't want to come out of the rail or the lower intake and you end up ripping an O-ring. Just little stuff on an old car.

I don't see ZZP listing an S/C oil any longer, but the GM oil is PN 12345982 (I'm looking at a bottle now). The GM stuff is all I've ever used.

Dexron VI is used in the newer trannies, and now all of their hydraulic steering systems (excluding HD recirculating ball gears). We still use DexIII in all the "old" transmissions.
If you're thinking about switching to Dex VI, you absolutely CANNOT mix the 2 fluids. They aren't compatible with each other. You would have to get a trans flush with a machine to make sure that ALL the old DexIII gets out, including the Torque Converter (which is what a flush machine will do).

+1 the power flush on the Dex VI. The issue there will be finding someone to do the power flush correctly, matter of fact the issues lead many/most people to recommend against power flushing. My take is read the posts about it on here and then find a shop to do it, you will know what to ask for.

The other thing is NEVER go back to Dex III once you have switched to Dex VI.

Abaddon wrote:

They don't make the "Blue Plate" Raybestos specials anymore for the 4T65E. Just FYI.

Yes, if you hunt you can get sets but it's harder as time goes on, especially now that the only folks with them seem to be the shops that *know* what they've got.  THOSE were first class frictions.

That said, the Reds are pretty good...

EyeDoc1 wrote:

Good morning everyone.  Reason I asked is you (AlbertJ) and Abaddon are frequent posters and obviously knowledgeable, so tricks and tips picked up from you guys is helpful to me...and maybe even a wider audience who don't ask the question (but wish they did).  I spend a lot of time looking over the forum in the evenings and have gained a lot of knowledge, esp on the HVAC posts.  Now I've gotta look over the T1-1/4 vs T1-3/4 bulbs, but that's not an appropriate topic for this thread, as we'll keep it to the 3800 Series II motor.  One thing for Abaddon...what do you mean by <>  Does that mean you might wind up breaking or destroying things, or you just get part happy and figure..."well, I've gone this far...might as well replace this, then this, and why not that".  Just want to do it once and be done.  As for Supercharger oil, your preferred source...dealership or alternate?  I'll take that tip about the transmission and change gasket and filters, as I'll have to check Rock Auto for a set.  Didn't even know they make a Dexron VI.  Figured they stopped at Dexron III or maybe IV, if that was made.  I gotta pay more attention to fluids.

Abaddon's better than I am; just look at the post count/merit ratio...

Don't either one of you sell yourself short on the advice issue. Given that a lot of fluids are "Backwards Compatible", it's a logical conclusion that mixing Dexron VI with Dexron III is not big deal, but what Abaddon suggests falls in line with the Shoeless Joe Jackson quote of "Say It Ain't So". And if Abaddon says they aren't backwards compatible, then given the age of the car and knowledge that any shadetree mechanic flush in the driveway only nets about 1/3 to 1/2 of the fluid, Dexron III it is. Another reason I trust the forum is knowledge shared by a lot of people who've gone there before me. I've seen a few YouTube self-flushes that resemble giving your car a hospital style IV to get out as much transmission fluid as you reasonably can without resorting to taking your car to visit places that are questionable in their flushing techniques to make me nervous enough to just stick with the Dexron III and drive the car till both doors fall off. I mean, I'm 67 and a member of the Medicare fraternity and do this for fun and enjoyment just to see if I can do it without totally screwing things up. Like I said, excellent part changer, so-so mechanic, and on a first name basis with our local Pick 'n Pull who see me coming with my toolbox and surgical gloves. Been learning ever since getting stuck with a bad fuel filter on a '62 Ford and swearing I'd never be left in the cold and rain with wet feet ever again if I could help it. Words to live by.

You can do the fluid exchange yourself, it's just that you have to change the fluid and filter in the pan first anyway. In general, you can drop the pan and change that fluid and the filter first; reassemble, top up the fluid, and then run the flush by disconnecting a transmission line at the cooler (the radiator on a Riv) and using a hose to guide the fluid into a (big, big) bucket while adding fluid thru the dipstick hole. One professional trick is to use clean used fluid of the right type (dex II, VI, or what have you) to pump through and flush out all the dirt. The more sophisticated transmission flush machines have filters that deal with this little problem. There are lots of instructions on the Web concerning this. And you're right, many of the YouTube videos on the topic are flawed in that they are incomplete or incorrect.

Dex III is OK; Dex VI performs better and does not need to be changed quite as often.