2002 Pontiac Grand Prix coolant leak internal, cylinder 1 misfire

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TWINDRAGON73
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  • 3 POSTS
Cylinder 1 misfire. Coolant was leaking by coolant temp sensor in lower intake (intake it's self not a gasket). Put coolant stop leak in it and the leak stopped. But it was drinking antifreeze as well. Took it down to head gaskets. reading the valves 5 cylinders was getting antifreeze into them cylinder 1 was real bad both valves white. The other 4 cylinders 1 valve each was white and cylinder 6 was burning normal. Lower intake was good. Head gaskets look okay. Look being the key word. Both heads was cleaned and crack tested and he said they both are good. Now my question is do you think that there might be a chance that the lower intake is the culprit and if so have you seen it before
Nov 19, 2013 at 5:50 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
what engine? both the 3.8 and 3.4 or 3.1 had both issues so if you put it back together with new modern stuff it shold be ok. If it were the intake on a 3.1 series engine there soulw be coolant either by front or back of engine. i'd say a head gasket though they need to be looked at very carefully tofind it.
Nov 19, 2013 at 7:58 AM
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