99 Bonneville Intake

dobiefloyd · #1 Nov 1, 2009, 03:22 PM

I had to replace a lifter in my Bonneville (non supercharged) and now the engine hydro locks. Any ideas before I tear it apart again.

Car ran great for 10 minutes and then started running a little rough and then check engine light came on. Random multiple cylinder misfire. I turned the car off and tried to restart and it hydro locked.

This is my first intake on a 3800, something obvious I missed?

kitch428 · Nov 1, 2009, 03:33 PM

Sounds like the intake gasket is leaking coolant into the intake runner. Is coolant spitting out the plug hole while cranking over?

jab08 · Nov 1, 2009, 07:36 PM

I'd have to agree with kitch you have a leaky intake the 3800 also have been known to crack on the upper intake at the plastic in 2 areas one is where the bolts tighten down be real precise with the torque and the other is at the coolant passage

dobiefloyd · Nov 1, 2009, 08:07 PM

All cylinders have water. I pulled the upper and it was full of coolant, it filled up as the car was running. All the torgue was right, 89in-lbs. I didn't have the specs for the throtle body so I went with 89 again. Also I did't have the sequence for the upper so I went similar to the lower. Where are these cracks specifically?
Like I said I was chasing a bad lifter but upon disasembly I found there was leaks with both the upper and lower intake, but not a problem yet.

Any ideas?

dobiefloyd · Nov 2, 2009, 01:56 PM

I have checked for cracks but can't see anything visible. Can't find anything I did wrong?

jab08 · Nov 3, 2009, 07:30 PM

you sound like your on the right track if it was cracked you would have come acrossed it the torque for the throttle body is the same as the intake bolts and as long as you started at the middle of the intake and worked your way out your good with the sequence chances are you had a seal in the gasket that was bad aka defective gasket but you probably have it fixed now let me know how it does and good job

dobiefloyd · Nov 12, 2009, 05:01 PM

I found the problem. The EGR tube goes up through upper plenum between coolant passages. After time the plastic burns through. By removing it and reinstalling it made it a big problem, drank coolant as fast as you can pour it in. The plenum and gaskets have been updated on the 3800 to fix this common problem with them.



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