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General Motors Corp. is recalling 207,542 Buick Regal and Pontiac Grand Prix sedans over a risk they could catch fire, and warned their owners not to park the cars in garages until they are fixed.

The automaker said Friday it is recalling the 1997-2003 Buick Regal GS and Grand Prix GDP models with 3.8-liter supercharged V-6 engines.

During hard braking, oil can leak from the engine onto the exhaust manifold, and fires can start if the oil gets hot enough, the National Highway Traffic Safety Administration said on its Web site.

GM spokeswoman Carolyn Markey said the problem has caused 267 vehicle fires and six injuries, five of them minor and one moderate. It also has caused 17 fires in structures, GM said.

The NHTSA said that if the exhaust manifold is hot enough and the oil gets below a heat shield, "it may ignite into a small flame and in some cases fire may spread to the plastic spark plug wire channel."

Markey said GM sent letters to the owners on Thursday telling them the vehicles are safe to drive, but they should not be parked in garages or carports until the problem is repaired.
http://money.excite.com/jsp/nw/nwdt_...&date=20080314

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uncledaddy

I'm thinking that the only place for the oil to leak out would be from the valve covers. But if that's the case then they had better recall every vehicle on the road. As engines wear gaskets sealing the valve covers tend to leak regardless.

I've seen serious cases of leaky gaskets pouring onto exhaust manifolds in the shop but no fires yet. I have heard of them though.

I wonder if there is another area where the oil could be coming from on these recalls.

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johnnymk

Doesn't the supercharger have bearings which must be lubricated?

I know that the turbocharger on my 2.3 Mustang has a separate line from the engine which lubricates it's bearings

mechmike0034

The blower on these has its own internal oil supply.

It is a valve cover leak - here's the bulletin...

Here's the procedure, blow-by-blow...

I'm suprised that other L67-equipped vehicles aren't affected - just the W-body cars...

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uncledaddy

Well, you've confirmed my suspicions. However I still don't understand this. These 3800 have always had eventual valve cover leaks in the front. I assume that 3800 S/C may show leaks at earlier stages due to higher crankcase pressures, but regardless of what type of gasket is designed it will eventually leak, right? Is there really a need for a recall or just a need to inform owners of maintenance?

mechmike0034

With the occurrence of 267 "thermal events" (GM engineer-speak for fire) I would think the recall is necessary.

I suspect the issue is more prevalent in the W-body cars because these cars have a smaller underhood area than the other vehicle models that use that engine (Bonneville, LSS, Riviera), which could mean higher temperatures and quicker gasket deterioration. Add that to your thought about higher crankcase pressure and it makes an interesting theory...

The engine may also be at a different angle in the W-body. Perhaps it is tilted farther forward to clear the hood. It is a wide 90-degree V6...

I'm not an engineer (I don't even play one on TV) but, like you, I spent my share of time fixing engineer's mistakes and trying to determine the root cause.

I don't know any of this for certain - it is all conjecfture on my part, but these are the areas I'd look at first were I tasked with solving the problem.