GM3800 Supercharged intake leak

2000 Grand Prix GTP with 225k on the clock. (It still runs 13 flat at 120mph on all season tires and gets over 30mpg). I put intake gaskets on it a little over 100k ago. <-- my friends across the pond have to convert units themselves.


This is not really a question, just an interesting case. Recently the throttle body gasket blew out and it was dumping coolant in the intake. It happened at near WOT when it shut down. With ALL the spark plugs covered in coolant, I assumed an intake gasket, but I saw the bad gasket when I pulled the throttle body. It runs fine now with new plugs and a gasket. Compression test was good.

Here's where it gets strange. It now makes a loud, high pitch whistle when in boost. At this point it stops increasing power with increased RPM. My assumption is the blower gasket is leaking. We'll see this week

Can someone help me out with a P1653? MIL is not set. Pass and fail on each ignition cycle.

I’m finding conflicting information online, but I don’t think it’s related to the assumed intake leak.

The ABS / TCS module is bad on this car and has a stored fault code for it

1. With a capable scan tool, command the low oil lamp on and off.

2. If the lamp does not turn on consistently, ground pin 6 of the PCM clear connector, Brown/White wire.

3. The low oil lamp should now be on steady.

4. If the lamp is on steady only when grounding the Brown/White wire manually, check pin 6 connection.

5. If the connection is OK, replace the PCM.

6. If the lamp is not on steady with pin 6 grounded, check the circuit, #1173, through the underhood fuse block.

7. Also, check the low oil level switch input to the PCM, pin 58 of the clear connector, Brown wire.

8. This wire should stay near 0v if the oil level is proper.

I am not sure with the S/C version but i know the 3.8 with the plastic intake melted around the EGR part and causing antifreeze to leak in the cylinder. It was a faulty EGR valve stuck open causing this problem.

Good grief!

The Autel is showing it as "Driver 2 Line 3" on a code scan. I couldn't figure out what that was referring to, and apparently my google-fu was severely handicapped because I couldn't even find a description for that code.

I went back and entered the code manually in DTC Lookup on the Autel and it listed it as the oil level sense circuit.

eliteautosolution wrote: I am not sure with the S/C version but i know the 3.8 with the plastic intake melted around the EGR part and causing antifreeze to leak in the cylinder. It was a faulty EGR valve stuck open causing this problem.

The EGR comes in on the plenum under the throttle body. Here's the coolant passage that blew out. Looks like it's been seeping around the bolts for a while.