Thanks to all for the replies/input.

Like I said, it was a Denver Chevy dealer that diagnosed this new intake manifold gasket leak (and I could see some wetness on the exposed parts of the gasket). The only reason I used this (stupid) dealer was because they had a special on oil changes. While there, they "diagnosed" four problems: bad catalytic converter (rattling noise), radiator leak, intake manifold gasket leak and front cover oil leak (very minor). They wanted $4,200 to fix them all.

Took it to a local (apparently honest) mechanic today:

Turns out that the hose directly above the gasket wasn't tight enough and that it was leaking small drops down the back of the hose and onto the gasket, making it look like the start of a gasket leak; so no intake manifold gasket will be needed after all. Radiator leak: another hose (top/left or radiator) needed to be tightened; catalytic converter: he said it is bad (said it rattled when he hit it with the palm of his hand) but that if it's not causing performance problems, I could let it go for a while.

Anyway, decided to have them replace the cat (just so I don't have to think about it anymore). They'll do it a couple of days from now; $455 (seems kind of expensive to me, but it's cheaper than three other places I called).

Thanks again for the advice.

 

Good news on most of that. Again, I don't trust any mechanics especially dealerships. $455 for one cat and 2 welds seems really high also. A cat either works or it doesn't. The rattle most likely associated with it is the heat shield which tends to come loose on older vehicles. I would save the money and continue to run that cat. Thats just me though. If $455 is worth your piece-of-mind then have at it. No cat codes=Good cat converter. My opinion. Good news on the rest though.

 

A rattling cat converter is not always the heat shield. The guts of the converter actually come loose inside the cat and rattle around. I just replaced mine.

The noise was pretty bad at times... I let it go for a couple of months until it threw the PO420 code. Replaced it with an OEM style unit which is one piece from the manifolds to the muffler. Cost $350. wholesale for the part alone.

If your cat is that same style, I would discourage a "cut & clamp" solution. Everyone I spoke to who has tried that got the codes back...

Anyway, I shook the old cat when I got it out. It was definitely rattling from the inside.

peace

.

 

Thanks, MC.

Hmmm, well I have already scheduled an appointment for the cat. Think I'll just go ahead and do it (just so I don't have to think about it anymore). The $455 price: Yeah--I agree; seems high. BTW, they don't even have to weld. It's a direct-fit install, according to them. But other estimates were even higher. Also, coincidentally (or not?), this cat rattling noise started right after I had the vehicle smogged a couple of weeks ago. I remember just before leaving the smog station that one of the employees was using a pole mirror to look under the vehicle. Don't remember them doing that with any of the other vehicles there. ?? Should have inquired but was in a hurry to leave.

I'm now gonna wait for the next surprise with this Blazer. I have PM'd the hell out of this thing (every conceivable PM measure) but it seems like every year something happens to it that costs me a grand or so to fix. And it only has 86k on it. Oh well, guess it's cheaper than buying a new car.

Battery: I'm off to buy a new battery for it (4-year replacement). Looks like the smartest/cheapest way to do this is to get it at Walmart. From internet research I've done, it appears that the Walmart EverStarts are no more "generic" than Bosch batteries, for example. Seems they're all made by Johnson Controls.

 

Okay, now you've got me worried. When you say "cut and clamp," are you saying that all cats on a '96 Blazer S10 are welded in from the factory and that any mechanic who tells me he can "direct fit" a new one is not being forthright? That he'll have to cut the old one out and then somehow clamp the new one in?

I just dropped the car off to have the work done tomorrow morning but I'm not going to be happy if that's what they're planning to do and I'll have to call and cancel the work in the morning if it is.

 

Mine is a 2002 and the OEM cat assembly includes the Y-pipe to the manifolds, pre-cat, hanger, and flange to the muffler. It's a big part and kind of expensive. Some guys save money by cutting out the cat itself and welding or clamping another one in.

A direct fit unit should bolt in OEM style. I can't vouch for this, but I think that the cat on the '96 is a smaller assembly with pipes and flanges on each end but not the Y-pipe. If that's the case, the $455 installed price seems about right from a dealer. Mine was $350 for the part alone from a local supplier.

If you're unsure, you could call in the AM and ask, but it sounds about right to me. Let us know how it works out.

peace

.