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2005 and Earlier Chevrolet Impala



  • atbearatbear Posts: 322
    Dexcool is not the problem. And I'd say that less than 1% of the population is pretty uncommon. I'm sorry it happened to you, and I'm glad you caught it and got it fixed, but this is still not a common problem. Thanks for warning us none the less. And good luck with your second manifold.
  • charts2charts2 Posts: 618
    To learn more about the cause of this problem got to Search: 3800 engine manifold problems.....The first heading surfing down "LEARN HOW TO BE A SURVIVOR WHEN PROBLEMS ARISE BY DOUG down halfway again to "Buick 3800 vin K Hydrolock"...It explains the problems with the plastic intake manifold.
  • atbearatbear Posts: 322
    After reading that article on the cause of the problem, I might have something that will help us. I will be getting this soon (I decided to get it way before I heard of this problem), but now it might be good for preventative maintainance, as well as performance gain! Here is the product:

    That is something formed by Jim Wierzbicki who owns a Grand Prix with the L36. He makes lots of neat mods for our motor, and this one was meant to help performance. But, after reading this article, it might help with the manifold problem. Check it out

  • Just had to ask.....
  • b4zb4z Posts: 3,372
    Teo doesn't post here anymore. I have an email address for him that comes back as undeliverable.
    He is registered with but doesn't post there anymore either.
    I think his last post there was May '02. I guess he is officially AWOL.
  • That coolant plug looks like a good workaround for the problem. Has anyone here installed it? How Much? How easy it is to put in there?

    I am not very mechanically inclined.
  • Just made an appointment for loss of coolant. The service manager told me he had just read a GM bulletin addressing this issue. He thinks from the tone of it a recall/update is coming for this, though it didn't say precisely that in what he read.

    Anyway, I'm bringing my car in, '01 LS with 40,882, this Thursday. I'll post how I make out.
  • larryfllarryfl Posts: 214
    I'm on the fence with this. I bought a 1984 Maxima new and got the 60K mile extended warranty - about the longest available back then. It definitely paid for itself in a string of repairs from 45K to 65K miles. Of course, I had to pay for the ones over the 60K mark. I kept the car to 120K miles and never had any other problems.

    The next warranty I bought was for a used '92 Infiniti Q45 with 89k miles. I bought a 24/24K warranty for that and THANK THE LORD! That car had over 20K in repair work done under that warranty. Towards the end, I actually had to sue the warranty company to get the last $4500 paid. Needless to say, the car was traded immediately after it ran out.

    BUT, I traded on a used '95 Olds Aurora w/ 50K miles that I still own. Because I was gun-shy after the Q45 experience, I bought a 24/24K GM Bumper-to-Bumper warranty for $1500. When it ran out, I had made only 1 $125 claim. Of course in the 8 months since, I've spent about $1500 in new radiator, AC compressor, Water pump, etc. Oh, Well.
  • Extended warranties are another form of insurance. Is there for when you need it. The same argument can be made about car insurance. Since it is mandated by law, you have no choice but to pay for yearly coverage. If you never file a claim, oh well, you made the insurance company richer. If you do use it, is there for you.

    The same can be said about EW's. Depending on the car's warranty repair history and overall reliability stats for the make/model, one needs to make a decision if it is worth to "prepay" for any unexpected breakdowns down the road or to take the gamble and hope for the best.

    Let's face it, Impalas are great cars and probably one of the best qualitywise products put out under the bowtie brand by GM in many years. But these cars still do not match the reliability reputation of the Japanese competitors and things will surely break after the factory warranty.

    The ISS and the plastic intake manifold are 2 prime examples of costly to repair items that at some point will fail again. Thanks to the GM beancounters, Steering shafts and Intake Manifolds are part of the wear and tear dept.

    I think the Imp is a terrific car in many ways and I don't have a problem keeping it for the long run, but not without an EW contract. I do not trust these cheesy plastic manifolds at all, not specially after one that "melted" under normal use at 18K miles.

    EW are a personal choice, and I don't think you can't go wrong getting a good service contract to cover for unexpected repair expenses. Chevy parts perhaps are cheaper than many other makes and models, but labor rates is what makes auto work in these cars so damn expensive.
  • garywgaryw Posts: 116
    Not sure about GM's policy but some auto manufacturers will not charge to repair the same the thing twice. My Volvo was covered under this little known policy.
  • I doubt GM would have a policy like that. Would be nice though, but doubtful.
  • atbearatbear Posts: 322
    That coolant plug just came out about 3 weeks ago. I only know of a few people who have it on their cars. It's very easy to install, there's only 3 screws to unscrew on the throttle body (you can easily do this install if you choose it). It's main purpose is to keep scalding hot coolant out of the throttle body to keep it cool (a cool throttle body creates more power), but by keeping the coolant out of the throttle body (according to that article charts2 posted) it might help solve our potential problem with the manifold. They can be purchased here:
  • I was wondering if the Coolant Plug can void our powertrain warranty....toughts?
  • atbearatbear Posts: 322
    You cannot have your warranty voided simply by having something installed. To have your warranty voided, the aftermarket product must actually cause the problem, and the dealer must prove that it was the aftermarket part that caused the problem. I wouldn't worry about it at all, but it is still your desision.
  • dieselonedieselone Posts: 5,727
    My wife's 01 Impala 3.4 w/ 39k miles just got out of the shop because of the infamous ISS problem. They lubed it up and it seemed to do the trick. I don't know what the bill was since it's a company car and all repairs go directly to a service company that manages their fleet. Another problem that has developed is the low coolant warning light. It comes on immediately after start up and will go out after about 15 min. of driving time. I've checked the coolant level and it is topped off. Overall it has been a good car, not exciting by any means but a good car. It will be going away at 50K for a replacement. Word has it the wife's company is switching over to Ford so it looks like an 03 Taurtus will be in the driveway this summer. I'm sure it will come with the despicable 3.0 vulcan, YUK!
  • I'm a little confused. How is the throttle body coolant plug supposed to solve the issue of a warping intake manifold? I thought the warping was between the upper intake manifold (plastic) and the lower intake manifold (metal). Is the warping actually between the throttle body and upper intake manifold?
  • Have someone check the coolant level sensor in the expansion tank. It could be that the sensor is sticky.
  • atbearatbear Posts: 322
    Did you read the article about the 3800 manifold problem? From what that said, it sound like the coolant coming from the throttle body might be the cause of the warping.
  • Be aware that the 3.4L V6 in the base Impala is infamous for manifold intake problems and in a much greater margin than the 3800 V6.

    The 3400 V6 is used primarily in GM's current crop of Minivans, the Alero, Grand AM, Aztek and Buick Rendezvous.

    The ISS problem is a fact of life in these cars, but I'll take that any day over an engine/manifold leaking coolant.

    It seems that the ISS relube has had some degree of success as I see that complaints about this item have minimized since it was introduced in a new TSB.

    Would like to know how much your company has paid for the ISS relube out of warranty.
  • atbearatbear Posts: 322
    Here is the article I a refering to:

    And, here is the exact part I am refering to:

    "This passage is partially protected by a metal sleeve that sticks up from the lower manifold, but that doesn’t keep the heat from the hot exhaust gas from damaging the upper manifold over the long term. When the plastic deteriorates, it exposes the coolant passages used to preheat the throttle body that are located on both sides of the EGR passage. Then, when the engine is shut off, the pressurized coolant runs down through the manifold, past an open intake valve and ends up hydrolocking one of the cylinders."

    I don't know if the coolant plug will actually help, but I was just bringing it to light to see if it might be a fix. I have contacted Jim Wierzbicki about it to see if he believes his product could serve this function. Stay tuned

  • Thanks for the article. I would be interested in hearing what Mr. Wierzbicki says but I think this is two different issues. Hydrolock describes a condition where one or more of the pison cylinders fill with water. Water does not compress so when the valves close, the piston cannot move up. I don't know if the ERG system passes through the intake manifold in the Impala. I thought it was bolted on somewhere else, but right now, I couldn't tell you where.

    From the photos of the plug and of the K intake, it looks like the hole developed in the intake and the plug seals the throttle body. To fix the issue described in the article, one would have to remove the intake and fill the passages with epoxy or something.

    I wonder why the plastic manifold makes more power? Maybe they can form the air path better in plastic?

    I wish they had said how old that manifold was.
  • atbearatbear Posts: 322
    You're probably right.. Since I don't have a tangible model of the problem, it's hard to visuablize all of the components from that article. The coolant plug would still be a good mod, even if it would have minimal effects on this particular problem... Thanks, night_owl
  • Hey check this out. I tried to post the link, but Edmunds won't let me post a word with greater than 115 characters.

    "My 98 Bonneville SE 3800 V6 automatic, had a small coolant leak between the throttle body and the plastic intake/plennum. When the local service tech took it apart he said there was a pin hole in the plastic intake/plennum. The car only has 48k miles on it and he said this was a pre-mature failure and the second one he has seen on this model. He suggested after he makes the repair, I take the failed part and invoices to the local Pontiac dealer and attempt to get reimbursement, even though it is out of warranty, because it should have lasted much longer. Do I have any chance of recouping $$ from Pontiac and is this a common problem?"

    "Here is an update.
    The local dealer contacted the D.S.M. and he said because I did not take the car to the dealer they would only reimburse me for 50% of what the warranty "cost" would have been, which came to $162.64. My bill at the ASE certified repair facility was $637.41. The intake manifold itself was $295.66. I took it up with Pontiac customer relations and they say what the D.S.M says is final and I have no other recourse with them because I am out of warranty.
    The problem appears to be an incompatibility of the new Dexcool antifreeze and the plastic material the intake manifold is made of. The coolant is eating though the manifold.
    I would be interested to know if anyone else has seen or heard of this problem."
  • pluto5pluto5 Posts: 618
    My theory is that the fasteners on these plastic parts are being overtightened, overstressing them and leading to cracks/failure. Easy to do with an impact wrench in the hands of a robot! Just my opinion. New Year's resolution: spend more time checking the Dex-Cool in my cars than posting on this board.
  • I would agree with you. Overtorquing would also warp the mounting flange.

    I did find a TSB that covers the leaking ERG area of the intake manifold. However it does not say it applies to the Impala. Various 1995-1998 GM vehicles with the 3.8 L engine (VIN K - RPO L36). It was issued in July 2001 so if it applied to the Impala (and Monte Carlo) it should have been incorporated. It has not been revised since then. I'll post the full text on the ImpalaHQ site later this evening.
  • The TSB I found was the one you cited earlier. Actually, the one I have is the updated copy. It doesn't cover the Impala, but it sounds similar to the problem you encountered.

    The TSB is posted on the ImpalaHQ site and I'll work up a How-To article on this later.
  • dieselonedieselone Posts: 5,727

    If you have the info on what the ISS relube costs, let me know. If the ISS creak comes back and they charge an "arm and a leg" we may just wait for the new car to come and not waste the $$$

  • Thank you. I'll be checking out your site later on tonight.

    Possible over torquing of the manifold bolts could cause premature cracks in the plastic intake. I think I read this somewhere a long time ago, but can't remember the source.

    Are there any aftermarket companies that make manifolds for the 3800 V6?
  • atbearatbear Posts: 322
    Which manifold are we talking about? ZZP makes performance intake and exhaust manifolds.
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