Hey guys, I got a small antifreeze leak to trouble shoot. It is wet on the drivers side, below and aft of the thermostat hose connection and it is not that assembly. It is below the throttle body air inlet and inboard of the exhaust heat shield. I'm reading a lot of "LIM" lower intake manifold ? references... Is that a typical problem area? one end more than the other? Could it be a rusted through freeze out plug? I had one with a pin hole on another car and it was also right behind the exhaust manifold.

Thanks in advance,

you may have a external LIM (Lower Intake Manifold) gasket leak
which is way better than an internal....

so other than the thermostat assy which it is not, there aren't any other connections into the water cavity?

No freeze plugs there?

There is a gasket that seals the LIM to the heads. That is probably where it is leaking. This is what Toddster was referring to.

I have a similar leak, going on for three years now. Was bareable by adding coolant every few months, but now getting worse. Pontiac Dealer told me it was a leak in the throttle body, but the price he wanted to repair it was outlandish. I know there could be an internal leak into the cylinders from this type of leak, but I guess this is an external leak from the throttle body to the outside of the engine. I was hoping someone could give me a basic rundown on how to remove/replace throttle body to renew the gasket on a 93 Bonneville SE. I have 160,000 + miles. If I can fix it I will, if not, it may be time for the glue factory.

Should be little more then unplug the sensors, disconnect the cables, undo 3 bolts and slide it off the studs. Then put new gasket on and reverse to install again. You will need to drain some coolant.

Thank you Dan, I'll give it a try.

Is there really a connection between antifreeze and the throttle body??? I'm living with the leak through the winter and I'm planning to replace the car so I can give it to my son. I'll do an intake manifold in warmer wx. I think I'm going to have to get the special tools to disconnect the fuel line, any thing else I might be missing???

Yes, there'* a small coolant jacket on the TB

I'd think Gib'* leak is most likely from the TB. Reasoning this out in my head, the coolant ports are a third of the way down the heads. It seems that it would be visible externally before the TB or it would be filling the 5th and 6th cylinders before reaching the TB internally.

I didn't notice what year and model of car we were talking about, but I've seen a few L36'* (95+ NA'*) do this and only one or two L67'* (96+ SC'd). From the leak description, I'd be thinking you have a 95+ NA. It'* an easy to replace rubber seal.