Hi all, I've got a '95 Buick Regal Custom. So it'* a Series I 3800 / L27. ~62,500 miles. Today my mechanic noticed a leak which he thought was probably coolant around the intake manifold. He commented that it was a common problem with the engine because of the plastic that was used in the intake manifold and that the replacement kit is metal. After doing some checking it seems all I can find is information about the problem with the Series II engines, which matches what the mechanic was saying. I hardly see anything about the problem with Series I engines -- so I'm a bit concerned the mechanic is jumping to a conclusion on the cause, having a Series II engine in mind. Is there a similar problem with the Series I? Is the fix basically the same, new replacement intake manifold kits are aluminum and don't fail as easily? Is around $600-$800 a reasonable cost for parts + labor?

Thanks!

If the issue is with the plastic upper manifold, then yes..there were some that were metal and can be replaced on it. However the S1'* weren't known for a leak there. Say maybe 1 or 2 out of hundreds that I've read about. The more common issue with coolant on that motor was the heater hose fitting that is screwed into the lower intake. It'* made of a plastic that degrades over time and simply cracks off and such. The replacement pieces are metal. Sometimes it does require the manifold to be removed for this to be done, usually not though.

Pricing is seeming a little high... give him a call and get some better names on what he plans on replacing. There'* not a "kit" that I'm aware of for the S1 motor to swap the plastic upper to metal.

Actually its pot metal, though it has the same disastrous effect.

The upper intake plenum also tends to warp and leak right below the throttle body, but I very highly doubt that'* the case at 62k miles. I bought my 95 Regal with 62k miles and I didn't have a single coolant leak.

I would replace that fitting first. Its right above the water pump. The replacement ones are metal, and these are guaranteed to break. No ifs, ands, or buts, it will break and its likely that it has broken on you. Have a look at that and then come back to let us know if that was it or not.

Neat. Didn't realize it was. Had been told it was different and didn't research further.

Yeah. This car left me stranded 3 times, and this stupid fitting was one of them. When mine cracked, all the coolant sprayed out. The other 2 times were for a bad starter, and then for a bad ground wire that I couldn't find.

Gah! Son of a b***h. Some white smoke started coming out of the engine on the way home tonight. Just had oil change and brake fluid flush done yesterday.

Anyway... the mechanic thinks it is actually both the hose and the upper intake manifold. There'* small leaks on both sides. At the hose it looks like there is some corrosion.