jaustinbell Posted July 1, 2011 Report Share Posted July 1, 2011 My sister's 1996 3100 Grand Prix has 184,000 miles on it. Last spring (2010) I got an oil report showing some coolant in the oil so I switched out the LIM gaskets. Sometime between then and now, the car began to leak coolant externally pretty heavily somewhere around the intersection of the LIM, rear head, and block. I thought I had noticed some warpage in the old LIM back in 2010, so a couple weeks ago I stuck 2002 3400 intake manifolds on there with a fresh set of gaskets. The damn thing still leaks. Same place. Coolant dribbles down from around the dummy distributor area, down both the engine and the trans. A lot of it. Now I'm suspecting that upper-driver's side corner of the rear head (gasket). There is zero oil in the coolant. Car runs excellently and no signs of coolant in exhaust. That's my story. I am done fooling with this car. I have better ways to spend my weekends. As benevolent as this leak may be my dad will not tolerate it in his driveway. Please, someone tell me I can just clear out the TB and air cleaner, slather around some JB weld or black RTV, and get on with my life. Quote Link to comment Share on other sites More sharing options...
alec_b Posted July 2, 2011 Report Share Posted July 2, 2011 Rare, but not unheard of. Especially if it got hot. It doesn't take much to warp the aluminum 31xx heads. Sounds like a perfect time to do a top swap! Throw 3400 stuff on there and away you go. Cheap too. Quote Link to comment Share on other sites More sharing options...
BXX Posted July 2, 2011 Report Share Posted July 2, 2011 It the timing cover gasket. 95% of the time, that spot they rupture in gets mis-diagnosed as a rear headgasket. And overtorquing the LIM bolts will warp the head mating surface, and get more leaks. Or just improper install as well. Quote Link to comment Share on other sites More sharing options...
jaustinbell Posted July 2, 2011 Author Report Share Posted July 2, 2011 Leak's on the transaxle side of the engine. Wouldn't a timing chain leak appear on the belt side? And yeah, you do have to be downright gingerly with those LIM bolts, don't you... I don't suppose loosening them up could have any positive effect at this point, do y'all? If it was my car I would do the big-valve head swap. Hell, I'm doing exactly such a swap on my personal Cutlass Ciera next weekend. But my sister drives the Grand Prix all day every day so down time's always an issue. Plus, I don't charge her a dime for parts--that comes out of my pocket. Come to think of it, the year-old LIM gasket I removed a couple weeks ago was blown in one place--driver's side rear head coolant passageway. Right around where the leak currently is. So maybe there is indeed a LIM mating issue there. But would I have to replace a freaking rear head to fix that? Hmmm... come to think of it, after my Cutlass Ciera top swap next weekend, I will have an extra pair of 1996 3100 heads... Do y'all think my cheap ass could re-use the month-old upper gasket set and get away with just paying for one new head gasket and 8 new head bolts? Quote Link to comment Share on other sites More sharing options...
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