: 96 Fleetwood Brougham Exhaust Manifold Bolts

12-02-06, 04:42 PM
Hello - just read in another post about the exhaust manifold bolts being a problem - can someone tell me more or direct me to where this info is? Thanks, Bob

12-02-06, 05:39 PM
The info isn't really posted anywhere specific, but here's a few good links:


Basically, they'll either break in half or the heads just snap off, and you're left with a slight leak and a bolt with no head stuck in the head--that has to be removed somehow. One "fix" is higher grade bolts, usually Grade-8 vs. the Grade-5 they used factory. I bought a set someone was selling on Ebay as a "kit", and still have them sitting in the package. This is an old link, but is what I got:

http://cgi.ebay.com/ebaymotors/GM-Caprice-Impala-LT1-Exhaust-Manifold-Grade-8-Bolts_W0QQcmdZViewItemQQcategoryZ33632QQihZ019QQit emZ8072696698QQrdZ1QQsspagenameZWDVW

From what I've read though, people have still had these break too, so they've used others (some mentioned in the threads above).

12-04-06, 01:01 PM
If you have an exhaust leak at the manifold then the nasties aren't making it past the oxygen sensors.... the sensor is getting false data and therefore reports back to the PCM incorrect data. The PCM corrects by sending bad air/fuel trims.
This will decrease MPG, shorten engine/cat converter life, and decrease power.
I would suggest getting the bolts replaced ASAP if you have an issue.

Some folks have been able to double up on gaskets (or use a really thick one) and "band-aid" the leak for awhile.

Often times the driver's side rear bolt breaks (most common one) and there is another fix if you have patience and guts. I've fixed mine this way before and can atest to it working. There is an unused bolt hole just forward of the rearmost bolt. You can drill a small hole through the manifold (and consequently the gasket) when removed from the car and add a small headed bolt (allen works best since head is very close to primary tube) to secure the manifold. Then you can just leave the broken off bolt in the head and forgettaboutit.

Removing the bolt (involes either drilling with a 90 degree attachment or welding) can be costly and very difficult.

12-05-06, 01:53 PM
You know, we checked mine and I do believe all the manifold bolts are there (or at least you could still see the head), but with some of the common symptoms like bad fuel mileage (anymore mine is just getting worse and worse), a decrease in power (light, but still noticeable), and even a weird "crack" sound I sometimes get at a warm start-up (no idea, but maybe related), I think I need to check mine again.

The links I posted, I had read, but I still wonder then what really the best choice would be for bolts. I have a "set" of the Grade-8 ones a guy sells from time to time, but it seems like even those fail--or at least did for a few people.

12-06-06, 12:47 PM
I'd say that any grade 8 bolt from the hardware store beats the crappy grade 5s that GM used in the cars when built. That is where I picked up bolts, right out of the bins at the hardware store. Just be sure to use grade 8s and take in the old bolts to use for measuring up length.

Otherwise GM actually has a repair kit with upgraded bolts (includes all studs, bolts, spacers, etc. for both manifolds). Dal will give you the best price and can better explain the contents, but I'm pretty sure these are grade 8s that were used as a fix since the manifold bolt issue was so common.

12-06-06, 01:44 PM
Grade 8, Grade 5... they are both usable, just depends on how much you will spend. Just remember to slobber all the bolts with never-seize... you will never have any problems again.