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Pontiac Bonneville General Maintenance and Repair



  • mlm4mlm4 Posts: 401
    Regarding the supercharger oil: I was under the impression that the s/c was a sealed system and that it normally isn't necessary to add oil. If it was low, was it always low, or does that indicate a more serious problem? I have not checked mine yet.

    If you e-mail GMPartsDirect with a specific part you are looking for (give them as much information about the vehicle and part as you can), they will look it up for you and e-mail you the part number. Worked for me.

    I agree that since the battery is under the rear seat (and inside the passenger compartment) it may last longer. Heat kills batteries, and under the hood it is very hot. Most batteries these days should last five years, although down here in Florida it is often much less than that.
  • Good news for me , I discovered that the gasket between the manifold and the throttle body was bad. The gasket was 14 bucks and I fixed it myself last night. The only thing I am worried about is that the dealer said that entrapped air in my cooling system could damage the under side of the intake manifold. I bled all the air out of the top of the thermostat housing bleeder, and hope that this will be enough. At least it wasn't the whole manifold job. I will keep my fingers crossed as to when the hammer will fall on this part. Does anyone know of a surefire way to ensure that all of the air is out of the system.
    I hope this solves this one for me . It only took about an hour or so to repair. Thanks , Bill
  • evandroevandro Posts: 1,108
    FWIW, the only TSB about this doesn't apply to the current engines. As you can see here, the TSB recommends replacing the lower intake manifold as well. However, the current engine has a different one that supposedly fixes the issue, as you can see here.

    I did confirm with the service assistant that the upper manifold # 17113136 does include the gaskets between it and the lower manifold and between it and the throttle body.

    What gives me the creeps is that, unless the original part was from a bad lot, just replacing the upper manifold doesn't address the issue... I was lucky that this time the coolant leaked outside the engine, for had it been inside we'd be talking about a potentially severe engine damage. :^(
  • theicemantheiceman Posts: 736
    The under-seat location does more than protect the battery from extreme temperatures, all that additional road crud, shocks/vibrations are dampened between the axles, etc. My Bonnie was built in May '00 so the battery is coming up on 3 years old, this is its 3rd winter - and it's been a brutally cold January here.

    Heck, I saw -30°C (-22°F) on the Bonnie's thermometer for the first time ever just last week! Started first time like a charm. I wouldn't even think of replacing a battery that can handle that at 3 years. Perhaps before next winter though...

    the (well-named) iceman
  • mfahey1mfahey1 Posts: 419
    That's all good to hear. I'll stop laying awake at nights wondering if my battery will croak at any moment. I did have the original on our older Caravan that gave absolutely no warning whatsoever. It died one day, graveyard dead, and you couldn't even start the car with a jump.
  • ohhawkohhawk Posts: 14
    Just had this problem repaired with mine as well....approx. $250. 2000 Bonneville SLE with 50,000 miles. Get it fixed quickly to avoid leakage internally. Ironically 2 days later I notice small noise in steering column when turning left at slow speeds. I've read about others with this problem and a tech bulletin has been issued on this. Inexpensive piece in steering shaft replaced and some lubrication....$140. These are the first items I've had to spend money on since purchasing the car new. Overall quite satisfied with the "new" Bonneville look and ride but I expect not to see the Service Dept. for quite awhile.
  • mfahey1mfahey1 Posts: 419
    Does anyone put anything on these as a preservative and if so, what do you recommend?
  • Finally replaced the plenum on my 98 Bonneville with 128,000 miles. I know the problem started a long time ago but for many reasons I just kept adding more Dex-Cool. A family member who teaches auto mechanics helped me do the job saving me alot of money. Depending on what mechanic you ask some say the Dex-cool is the real culprit with this problem others say the gasket material was insufficient for the job. The ironic part is that the Dex-cool does less harm to the engine if it gets in than regular anti freeze would. There was a large amount of sludge in the plenum and the next piece under it, so we had to remove and clean that also and replace the 3 gaskets for it. We did computer testing on the motor after the job and there doesn't appear to be any damage done to the motor from having the Dex-cool invasion. Bottom line for me on this issue is GM needs to get sore ears from complaints about this. The parts guy at the dealership we bought our kit from said they just received a shipment of about 60 units, and that they did 2-3 Plenum jobs a day. That's at one dealership!!!!! They need to admit the problem and step up to the plate and do a recall.
  • Dex-Cool can't be the problem because 1995 3.8s may suffer the degradation and Dex-Cool wasn't introduced until 1996. Its not gasket problem either because the gaskets do not leak on the manifolds with the degradation (95-98). (But the gasket can leak on a 2000-2001, although some dealers appear to be replacing the upper manifold also.) And you never hear of the problem in the Grand Prix which also used the 3800 Series II (I can't recall ever seeing a post in the Grand Prix threads here at Edmunds or the Grand Prix Sites). SO it appears that some combination of factors that occurs in some cars causes the failure. And as a non-safety issue it would be unlikly that a recall would ever happen.

    But the $550 you spent for the two manifolds and the gasket will keep you car going for a long time hopefully.
  • john325john325 Posts: 237
    It seems like the one year you didn't include in your post was 1999. I have a '99 SE. Is this year also susceptible to the plenum problem? I have about 65k miles on it, w/ no problems so far. Crossing my fingers...

    John B.
  • I don't have any facts to back up my claims other than a pontiac parts man and a couple mechanics. But I do believe that it was gasket failure on my 98 we just can't prove whether it was the Dex-cool or the gasket material itself to blame. You would like to think that a major company would stand behind a flaw that sees 2-3 repairs a day at one dealership? It shouldn't matter if it's not a safety issue. Are you aware of any differences between the bonneville and GP's that could explain the problems with the bonnevilles?
  • evandroevandro Posts: 1,108
    In the newsgroup you'd be able to find that this dreaded issue was present in all applications of the 3800, including the Montana and the GP and also under other badges, as the Impala and the Park Ave.
  • Evandro-Which issue? My point is- We are talking about 3 different coolant leaks causes. (And the Montana never used a 3.8L engine. The last 3.8 GM Van was the 1995 TransSpot which did not use the Series II that went into the Bonneville.)

    oldram51--If yours was a gasket leak then why did you repalce $500 worth of Lower Intake Manifold and Upper Intake Manifold (Plenum)? Again my question is--why is the majority of the posts Bonneville related when the engines went in to other cars and are the same as the Grand Prix? Could it be the water in Kansas (GP) is better the water in Missouri/Mich (Bonn)?

    John325--The 1999 Manifolds are not the same as the 1995-1998, so the degradation issue is not there. And don't remember any posts in quanity about gasket leaks.

    Lets try some math. I believe Pontiac sells less then 100,000 Bonnevilles as year, of which some (20%?) are supercharged so do not use the Upper Plenum. 1998 Grand Prix sales were about 130,000+ of which some were 3.1 V6s and some were supercharged. 4years at 100,000 and one year at 130,000 is 530,000 (Very High). 2,800 Pontiac dealers. 300 work days per year. 3(+) years of repairs. A 2-3 per day average dosen't look sustainable.

    Just raises more questions then it answers.
  • You need to reread my post and your references, I think there is some confussion. The "something wrong in the intake manifold" is the degradation of the Upper Intake Manifold in the EGR area. It effects Series IIs from 1995-1998. "There's no TSB covering more recent cars" because the part was redesigned and the problem dosen't effect them. "see the mechanic's opinion" clealy points out the changes, he says nothing about the changes not fixing the problem.

    "The my..", your Upper Manifold was replaced for an external leak not degradation that effected the 1995-1998s. I have seen friends who had their 2000-2001s fixed with just a gasket. So therfore your Upper Manifold MUST have been bad.

    Leak 1- Degradation 1995-1998
    Leak 2-Upper Intake Manifold Gasket
    Leak 3-Upper Intake Manifold

    It is possible oldram51 has discovered leak 4 but hasen't posted enough infomation.

    GM's 36/36 warranty will catch most of the 2000-2002s with Gasket or Manifold problems (3/50 for Gasket and 7/70 for Manifold in California Emissions Warranty states).

    And if it was just a question of profits, wouldn't GM be better doing a $500 repair then offering $3,000+ in rebates?

    Since none of us designned or built our cars, it is the age old question of when does it stop being the manufacturers problem and become the owners.

    ADDITION: you added a second link while I was responding. Ian talks about what I have been saying about the changed lower manifold, and what it should do. And he goes on to talk about the external leak which as I have been saying is a different leak on your car.
  • evandroevandro Posts: 1,108
    If the redesigned lower manifold solves all the problems, then why did my Bonneville leaked? The dealer didn't write the cause of the leak in the receipt, so I think that neither I nor you can say that it wasn't a warped upper intake manifold. If the thinner EGR pipe just decreases the frequency of warpage, who's to say that the new manifold in my car won't warp again when it's out of warranty? I can't answer these questions, neither can you and GM hasn't answered them to my satisfaction.

    Come on, it is not acceptable that a 15 month old car with just 17000mls on it has any engine problem. Whatever problem it was, manifold warpage or gasket, it's just not acceptable that it hasn't been addressed once and for all since '95.

    Why can't the Series II be as bullet-proof as the Series I or as most GM transmissions? Why shouldn't I expect the same level of quality in the Series II as in these two examples?

    It's about customer satisfaction. My bottom line becomes GM's when the time comes to replace the Bonneville. Enough said.
  • I'll try and discribe my problem better. We started noticing a coolant loss shortly after we bought the car with about 55,000 mls. It was always worse in colder weather. It recently started going through coolant more rapidly, coincidently we had a run of very cold temps. We didn't replace the lower manifold we only removed it, cleaned it and reinstalled with new gaskets. The plenum was warped and deteriorating and full of sludge. We also replaced the pcv valve and need to replace the M.A.P. sensor. As I said before we did a complete computer check of the engine systems and everything looked good and it seems to be running fine. Obviously I could have saved myself some greif if I had done this sooner but we didn't know until recently what the problem was. There were never any obvious coolant leaks or any visible in the engine oil, so we assumed it was evaporating off the engine and until recently the amount lost wasn't large so we just kept refilling when it got low.
  • Read the posts. Where does anyone say the revised lower intake manifold solves ALL problems. It only addresses the DEGRADATION of the upper manifold on 1995-1998. They don't WARP they rot out an inside wall to a coolant passage. The fact that no one with a 1999 has reported this degradation indicates that it is a possible fix.

    I have clasified your manifold as a possible leak source. I have been trying to clarify things by pointing out that there are THREE possible DIFFERENT leak issues involved in our talks. If owners want GM to accept any responsability, shouldn't the issue be identified? We could say that GM sucks (as some do) but where does that take us. We could say GM sealing technology leaves alot to be desired, and we would be closer. If we say that the design of the 1995-1998 lower intake manifolds leads to failure during the mandated California Emissions Warranty period therefore the California Air Resousres board should force a recall or extended warranty, then we have something we can work with. Identify issue, and resolution.

    It would be great if our cars never had problems, but as we were recently shown so tragicly, even the best man made items can suffer failures.

    I find it perfectly accetable that a failure shows up at 17,000. In fact I hope it would. Isn't that why there is a warranty? Defects in workmanship or materials, that is what a warranty is to cover. The world has settled on 36/36 as being an acceptable time for the blame to rest with the manufacturer. I would rather have it at 17,000 then 57,000 or 87,000 or 107,000.

    Perhaps for the recent cars we need to find out if checking and retorquing the manifold bolts keep things strait.

    We are all here for the same reason, to share and share alike. Our common thread is our car. What better way to relate. But we need to keep our focus on the correct spot.

    oldram51, per the links evandro provided, you have not fixed your problem because you didn't replace the lower intake manifold. How could the dealer not sell you this revised part if they are so experienced in its replacement and know that GM recommends it?
  • I guess i missed the need for replacing that from your earlier posts. If in fact they are doing 2-3 of these a day I definatly should have been told that. Which makes me wonder if GM is trying to keep the scope of this problem as low key as possible. Could you please tell me what happens to or what the problem is with the lower manifold as I did not catch that from earlier posts. Also how long do I have before problems resurface? Thanks!
  • john325john325 Posts: 237
    Thanks for your answer on the 99 Bonneville. I knew that prior year models had problems, but did not hear of any when I purchased the '99 at 1 year old, w/ 17k miles on it. My mechanic, non-GM I might add, is very aware of the 3800 engine problems. I hope I skate through without the manifold problems. Obviously if it does happen, I'm well beyond the warranty period.

    In regards to new car problems, I kind of side w/ Evandro. There's something about a newer car that has terrible problems before even reaching 50k. My mechanic has always advised me to buy Toyota or Honda. And you know, you always hear about them going 200-300k miles without many problems at all.

    I took a chance w/ another GM product 18 mos ago, a 2002 Buick Rendezvous, and so far have had my transmission, awd transfer case, & rack and pinion steering changed in the last 30 days, not to mention other more minor-type items. When you fork out $30k for a car, you just don't think these kinds of defects will creep-up. But as you said, thank goodness for the warranty.

    When a problem is persistent through a number of years, eg, Chrysler transmissions, GM 3800 engines, Ford Wiring, or whatever, you'd think these huge companies would take some responsiblity and get these things fixed. Perhaps that's asking too much. I know Chrysler still uses the crappy transmissions in their vans that have been going-out for 10-15 years. You wonder how they can do this in good conscience.

    I'm pretty sure the next car I purchase will be in the Toyota or Honda families. Our American corporations seem to be more concerned w/ their profits than customer satisfaction. Just my .02. Btw, thanks again for your reply on the '99.

    John B.
  • evandro has done all the research here. Follow his links to see the pictures of the revised lower manifold and read the bulletin. Not having the updated manifold puts you at risk of the degradation but who knows how long. As you noticed, does this mean that the dealership is doing 2-3 per day wrong? GM put out the bulletin so they can't tell dealers not to sell the parts.

    John325--American car companies might seam to worry more about thier profits because Americans do. Dosen't any American company have to wonder how Wall St and Main St will react to their every move? Perhaps Toyota/Honda would be different companies if they had a $19 Billion unfunded pension liability. Or was required to put over $3 billion in to the pension fund in 2003. Or if they spent over $500 million per year on healthcare for retirees. You are starting to see the rapid new model introduction take a little toll on the Toyota/Honda reputations.
  • evandroevandro Posts: 1,108
    I agree with you in some points, but I don't think that I should identify the issue in order to raise hell at the Renaissance Center. There definitely is something rotten in Denmark and it smells like anti-freeze... :-)

    Having said this, I wouldn't blindly fork my hard earned money on either a Honda or a Toyota just because the legend is that they run for hundreds of thousands of miles flawlesly. As legendary as it sounds, it just cannot be true.

    I always try to avoid 1st year model cars exactly because of that. However, the Series II has been out there for years and so has the Bonneville. I never took my Bonneville to the dealer for any repair whatsoever. That a badly designed flimsy plastic part spoils my ownership experience in such an amazing car is a certificate of stupidity to GM brass. :-P
  • Its been a good day. We are both looking in the same direction. I just believe a general complaint leads to a general answer. As far as what the future holds, two to three years from now there will be a whole crop of choices that aren't here today. And take good care of your Bonneville. My 1992 is closing in on 240,000 miles and I may want to replace it some day.
  • john325john325 Posts: 237
    If one reads Consumer Reports, your eyes are blinded w/ red as you see all the filled-in red circles throughout on just just about every item conceivable for Honda and Toyota. Call it legendary claims, I call it "track records".

    I did research the Bonneville here on Edmunds and in CR as well, and the rankings weren't bad at all; but their rankings paled when compared to Honda & Toyota. Btw, I almost bought an Avalon, but instead I bought the Bonneville SE. Don't get me wrong, I really like the Bonneville. And so far w/ 65k miles, the only problem I had was a muffler which was changed at about 30k. So, re: the Bonneville, I can't complain.

    But when Chrysler, GM, and Ford continue pumping out materials that they know are defective, something's wrong. And I can definitely understand the unfunded pension problems, and multitude of other financial woes that American Corps. are facing. But, as I said before re: the Chrysler transmisions, they've been bad for over 15 years. I would think somehow, somewhere along the way they would correct a bad situation. The same w/ GM and Ford. Unfortunately, the only way the corps. face it head on is when the courts force them to do so, as in the recent case w/ Ford.

    My hope is that the car manufacturers somehow improve their quality, so that new car owners are not faced w/ inconceivalbe repairs, ie, evandro's at 17k. Either that, or extend the warranties to something more likely to cover the lack in quality parts/materials.

    John B.
  • evandroevandro Posts: 1,108
    Just don't put too much credit in CR ratings. They have more legendary than factual statistics...

    Having said this, reliability is not the only criterion I use when shopping for cars. In spite of their record or legend, neither Honda nor Toyota have ever put a grin on my face after driving them. THIS is a fact, at least when the time to put MY money on them came... ;-)
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,504
    I'm ready to replace struts on my 98. Has anyone replaced struts on their Bonneville and have comments about how they like them after 5K? These are for a LeSabre. Last time I used monroe road-sensing struts that were softer in the middle of their stroke. They lasted 110K before I traded that LeSabre off.
    I want a controlled ride (not soft like original). But I don't want bone-shaking rides either.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,504
    I never placed much faith in CR's choice and ratings. The subscribers to the mag are not a broad section of American buyers (I read it at the library or Krogers). The ones who choose to respond to the questinaire they send out are the ones who either have a gripe about their American brand car or they want to be sure their choice of a foreign car has been a wonderful choice with no problems.

    I've worked with enough foreign owners through my 3 decades that I figured out pride in a foreign car will have people not admit they had problems. Too, earlier the dealers had people so cowered that they had to bring the car in for service every so many miles for lots of money and didn't dare go any where else, foreign owners tended to service the cars better than Amer. owners (70s & 80s) who put in gas and changed the oil when it wouldn't drip off the dipstick anymore. Too the dealeres did some hidden fixes while cars were in for repairs that owners didn't even know they did; that helped the car's image of never having any problems.
    I've listened as the Camry buyer had to put new rotors and pads on a 2 year old Camry because of rotor damage already. I've listened to the no start or dead on way to work stories.

    I've been monitoring some honda and toyota groups and other parts of Edmunds and find the same tenacious protectionism of the car's image is still there in some owners. I think there must be sales people or company peoplein some groups to keep acting as cheerleaders. I've ridden in them, Accuras on down, and I chose the GM Bonnie/LeSabre type car.

    All cars have faults. If you change oil often and before the car needs it, you'll get 200K out of any engine. Don't tell me only honda and toyota cars are built to last. It's the owners. If only CR got the idea...

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • I think you make good points. I also agree with evandro - reliability isn't everything. Of course, your grin will quickly disappear if your car leaves you stranded in some Northern backwater in the middle of a January snowstorm!

    (all the same, I checked out the Avalon too & was generally unimpressed with the car and simultaneously appalled at the price point.)

  • john325john325 Posts: 237
    I've used CR as a point of reference because it's always been around, even when I was a kid. I, of course, "always" use Edmunds as a resource as well to evaluate any auto purchase.

    However, my "best overriding resource" is my mechanic who is one of the top mechanics in the SF Bay Area, as well as a personal friend. He's also one of the most honest and fairest people I know. I place more credibility in him than any publication, internet site, etc... And it's he, who really has no axe to grind, that advises folks to highly consider Honda and Toyota. So, one can find fault w/ CR's methodology of coming up w/ their results, but it's funny that it matches the opinions of some of the top mechanics in the field.

    I might add, my mechanic did check out my Bonneville and gave it his "blessing" before I purchased it. He had also forwarned me that earlier model years had manifold problems.

    As I'm 6'1" and about 225, I prefer a car w/ some room if you know what I mean. And that's the main reason I steered towards the Bonneville and away from the Avalon. And like I said, so far it's been pretty much problem free. I have the oil changed about every 3-4K miles. Maybe I'll be luckly like montanafan, and it'll go for another 100k without any major problems.

    John B.
  • Thus far, I have owned 10 Japanese cars, 1 European, and 1 Japanese-US hybrid (a Mercury Villager). My experience with Japanese was 6 Toyotas and 4 Mazdas - all reasonably positive.

    Like you - I have a trusted mechanic. Like yours, mine favours Toyota and Honda - but less the latter and mine tends to be a tad Euro-centric. He practically gushed when he first inspected our Volvo - it turned out to be a lemon and will be my last Volvo ever - and 'twas he who twisted my arm to get the Villager when our thoughts turned to a Minivan. "All the important components are Nissan" said he. Turned out that those were all the components I had difficulty with - a tranny rebuild (before 50k) and a chronic coolant leak topped the list. Ironically, the Ford stuff was bullet-proof.

    Go figure.

    That experience made me more open to doing something I'd never dream of doing before - actually test driving a US car. Certain makes are off my list because of my perception of reliability concerns (Volvo, Nissan, VW, Chrysler, all Korean marques, etc.).

    My first tester? The Aurora. SWEEEEET. Then an Avalon. Not meaning to disparage the Av but it was no contest - the American car was just better executed and more powerful and toss-able (for a large car). Once I checked out the '00 Bonnie, I was sold by the solidity, drive-ability, interior room, intelligent features, and the price point. My mechanic also gave it the nod (of course, after the Volvo and Villager fiascos, I listen a little less to him now).

    I've had two small problems with the Bonnie - an LED in the stereo and the height sensor went last week - but she's been otherwise bulletproof. However, it's put me on notice that this car has a lot of electronic features that could be expensive to repair, so I'm talking with my dealer about an ext. warranty - a small expense, really, in the scheme of things.

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