Supercharger inspection and maintenance

[Reatta Man]

I'm going to be purchasing a used 1999-2001 Regal GS in the next couple of weeks. For the price range I'm looking at, I will likely be purchasing a car with 80,000-100,000 miles on it, and intend to keep the car for quite a while.

I'd like to know specifically what I need to inspect in and around the supercharger on these cars. I'd also like to know if the oil in the supercharger is a big concern, and if so, how to change it. Do you simply remove the plug near the pulley assembly and make sure oil is visible inside the case, or should I plan on changing it based upon the years and mileage?

I'll be using this car for some road trips, so anything I can do to avoid trouble on the interstate is top priority.

Thanks in advance for your help.

Joe

[BUICK RACER]

Although I haven't done an 'oil change' on a supercharger of the 3800 kind, I think it is not a hard thing to do. Just remember to put the drain plug back in before you put new oil in it. I'm not sure, but I think my mom even let my dad do the one on her '95 Riv, but it could be he told her it needed to be done and she paid to have it done!

[Reatta Man]

Roberta,

Thanks for the info. Do you know if there is a drain plug for the SC, and if so, what grade of oil goes back into one? It's been a while since I owned a 3.8 with the SC, and I didn't have it long enough (lease, turned in with 36K miles) to need to worry about the oil in the charger.

Joe

[Guest trofeo73]

I belive there is a special oil from the dealer. I think I saw it on thrasherperformance.com. It should be on many 3800 enthusiasts website, It should not cost more than 20 bucks, but I am not sure. It is said to check every 70,000 miles on my car, I have a 95 riv S/C and have not done it, but I plan to.

[Guest Straight eight]

There is a special oil, available at Pontiac and Buick Dealers.

The oil has no drain plug, but must be sucked out with a syringe,

or some type of suction devise. A small diamenter plastic tube will fit

in the filler hole.Make sure all the dirt and crud around the filler plug is cleaned before loosening the plug. DO NOT open the filler after the car has been running!

There is a pressure build up. Best to check and change first thing in the AM after letting it set all night.

There are many stories out there in the big city about whether to change or not.

My vote goes with changing atleast every 40,000 miles. It only take two small bottles for a complete change. When the old oil sucked out is dirty or black, you know you have done some real good towards extending the life of the unit.

[Reatta Man]

Thanks, Eight!

I'm with you; preventive maintenance is always cheaper than waiting for it to break, and it gives extra piece of mind.

I'm still negotiating with the guy. He wants $5500 or more, and so far I have agreed to $5200. We'll see....

Joe

[JohnD1956]

I have a 95 Riv and belong to the Riviera Owners Association. All the owners over there advocate changing the oil in the Supercharger before 100K, but funny thing is, some of them still seem to go anyway.

In my case I have 111K on the original Scharger. It is still quiet although I'm sorta on egg shells with it, expecting it to go bad. But last summer the intake gasket went bad, and I took it apart for that job. In the process ,observation showed the inside of the Scharger casing coated with sticky thick oil. The EGR valve dumps right into the Scharger intake, behind the throttle body. As a matter of fact I was even having trouble with the throttle sticking upon start up.

So I got a few cans of carb cleaner and sprayed away. Hit every surface till what I could see was clean to the metal. Also while I had it out, I tipped it on the belt end, removed the drain plug and let er drip out.

Now, the 2 times I checked the unit before this, the oil was always at the top ( basically up to the bottom of the drain plug) but not that much oil came out. I think I put most of one bottle of Scharger oil back in. When it took me longer than expected to finish this job, the Scharger had been sitting about 2 weeks, and I could barely turn it by hand. But it did turn.

When I started the car, the Scharger didn't turn at all. I turned it off, removed the belt and rocked it back and forth, . When I could get a full rotation I put the belt back on and everything was smooth.

I concluded the carb cleaner probably did not hit the back wall of the SCharger insides, and probably sludged up the works. But once it got going, everything was great. Of course that is the 95 SCharger, which is different than the one you are planning on getting.

Here's a few more things to watch for.

Seems everyone has had problems with missing under load. Usually plugs and wires first. But mine had a plastic nipple for the manifold to water pump by-pass hose. Naturally it snapped off when I was pushing the wires through that area. The replacement is metal.

Then the misses came back. The shop finally replaced the main processor, not because any codes showed, but because they could find nothing else, and this seemed to fix the problem. Then when changing the intake gasket, I had some dry rotted vacuum hose connectors. Probably from the heat. This car gets hot and stays hot for quite a while, unlike the wifes 93 Regal with the same 3800. That one will cool off at idle in 30 minutes. So that fixed the miss for a while, but now it's back. Now I'm figuring a tranny fluid change as it has never been done and the miss is at 45 miles per hour while the engine is loafing in overdrive. Drop it into 3rd gear and the miss disappears at the same speed.

So the short of it is:

Keep an eye on the intake manifold for antifreeze leaks,

Change the Scharger oil if possible ( they said a turkey baster worked good for this by the way)or at least keep it topped off.

Get the oil from GM shop. I think it was $7.00 per bottle, although that's probably equivalent to $30.00 per quart.

Consider some remediation for internal cleaning of the SCharger, and enjoy the pants out of that thing. I think there's nothing like the feel of that Scharger kicking in. I think the car could fly if it had wings...

JohnD

[NTX5467]

The first year for the SC3800, there was no mention of the supercharger oil in the maintenance schedule, but it DID appear in the 2nd year of production. Seems like the maintenance "check" interval was 50,000 miles, but it's been a good while since I looked at that stuff.

I concur that changing the oil instead of just checking it is the best way. Some of our techs have mentioned that they can tell when the SC oil has not been serviced as it has a stronger odor to it. I highly suspect that most of the SC3800s on the road have never had the SC oil checked, much less knowing that it had a special oil for it. Many might suspect it is lubed via engine oil as most turbos are (I remember those Turbo 3.8s that, when the seal in the turbo went away for whatever reason, "vacuumed" the crankcase of oil; factor in the typical "drive it and keep gas in it" mentallity and you know where that "deal" is headed).

By observation, there seems to be a good bit of information on the care and feeding and repair of the SC on the Pontiac Grand Prix websites and similar. That's usually where the performance mod information on the 3800s is found.

When we get a trade-in with a SC3800, usually a Grand Prix GTP, they usually are about 150,000 miles and have a noise in the SC. At GM OEM prices, it usually ends up on the wholesale lot. Most of the GP comments mention changing the front section to fix the noise problem, but I'm not sure what bearings are in the back side of the housing. I DID recently discover that reman units are available in the aftermarket (even from NAPA?), so there are other options than just from the dealer if problems which result in replacement occur. Seems like that one website also listed the differences in each of the SC units for the various years and which ones will bolt to what years of manifolds.

Most of the SC W-cars usually had the 3.29 ratio in the transaxle, rather than the normal 3.09 or so. Seems like there was a 2mpg EPA difference in the highway numbers, but I don't know if that was hedging or really accurate as that small change in axle ratio shouldn't equate to 2mpg at cruise.

To me, I would be more concerned about the health of the cooling system (evidence of whether or not there are any problems related to a poorly maintained cooling system with DEXCOOL in it!) than I would with SC issues. Many people are not aware of the "other" sources for SC units (in reman) rather than the new ones from GM, so that price from the dealership scares them right into another car without a SC on it.

Use your best judgment, change ALL of the belts, fluids, and filters, and . . .

Enjoy!

NTX5467