Gm 3800 Series 2 hydrolock

Tiny
ASHLEYKILLSME
  • MEMBER
  • 1999 BUICK PARK AVENUE
  • 6 CYL
  • FWD
  • AUTOMATIC
Hi, I have a 1999 buick park ave with the series 2 3800 n/a engine. The other day it hydrolocked while I was turning on to my road. I drove it about 100 feet into my driveway and shut it off. I took out the plugs and cranked it to get the coolant out, drainede all the coolant and cleaned the plugs off also drained the oil and re filled it. I wanted to run the engine for a minuit to see if it knocked or if it sounded like there was any internal damage. It started right up and sounded fine except for a light screeching sound for like 3 seconds. I turned it off and let it cool and it would not start again for the rest of the day. The next morning it started right up again and ran untill I shut it off and now again it wont start. Its getting gas and getting spark so I dont know what it could be. Im trying to figure out if its worth doing the manifold and gaskets but im starting to think hydrolocking may have caused valve damage or something I dont know. Any advice?
Friday, July 29th, 2011 AT 4:55 AM

9 Replies

Tiny
FACTORYJACK
  • MECHANIC
  • 4,159 POSTS
I had an oldsmobile that suffered the same concern, as a result of a failed intake manifold that allowed coolant through the EGR passage. After I replaced the upper intake and cleaned it out, It has had no problems since. You shouldn't have caused valve damage by hydrolocking, if anything, you will bend connecting rods.
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Friday, July 29th, 2011 AT 2:28 PM
Tiny
ASHLEYKILLSME
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Alright cool, do you have any ideas for things I should test to see why it wont start?
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Friday, July 29th, 2011 AT 11:17 PM
Tiny
FACTORYJACK
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At this point the concern is if there is any water in the cylinders, or that the spark plugs are coolant fouled(wet). The water makes it hard for combustion to occur. Remove the spark plugs and check them. If they are wet, the spark will not jump the gap, and the continuing fuel from the injectors will just add to accumulation of liquid. You will need to correct the internal leak, and either dry the spark plugs, or replace them afterwards. If you have spark and fuel, you have 2/3 of what it takes for the engine to run. The remainder is compression(air). Since you have a known concern with an internal leak, I would not suspect that you don't have air.
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Saturday, July 30th, 2011 AT 2:07 AM
Tiny
ASHLEYKILLSME
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Lower intake manifold gasket was bad so I took it apart and replaced the upper and lower gaskets, intalled new coolant hoses and elbows, thermostat, pluggs and wires, added coolant and new oil and she started right up and ran fine for about 45 seconds and then lost like one cylinder at a time untill it stalled and wont start again I removed the pluggs to see if it hydrolocked again but they where all clean. The only thing I noticed is that when I turn it over I can smell gas but theres no visible leaks and when I pull the pluggs they are drenched in gas. Do you think its possible im getting too much fuel and its causing my plugs to foul?
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Thursday, August 4th, 2011 AT 5:26 PM
Tiny
FACTORYJACK
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Are you sure they are drenched in gas, try and light it and see if it burns. If the plugs are coolant fouled, they will also smell like unburned fuel, as the injectors are till spraying while you crank. Remember what I said earlier about the upper intake eaten away between the EGR passage and coolant passage, allowing coolant into the intake? I would bet that you have a bad upper intake manifold.
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Thursday, August 4th, 2011 AT 7:03 PM
Tiny
ASHLEYKILLSME
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Put it on the code reader today and came up with b-1255- (air temp. External sensor circuit open) and p-306- (clyinder 6 misfire)?
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Friday, August 5th, 2011 AT 5:38 PM
Tiny
FACTORYJACK
  • MECHANIC
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The outside air temp sensor is irrelevant to powertrain system, only affects HVAC. You said all the plugs were wet, possibly the p0306 was the first code that set, other fault tests may disable once that code is set.
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Friday, August 5th, 2011 AT 6:46 PM
Tiny
ASHLEYKILLSME
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  • 8 POSTS
So I should clear the p306 code and check the codes again? I also got new plugs yet again today and it started right up and ran for 40 seconds again. So it will run with new pluggs for 40 seconds and then keeps fouling them out and wont start after that this is the third new set and every time I change them it starts up
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Friday, August 5th, 2011 AT 10:08 PM
Tiny
FACTORYJACK
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I am trying to tell you, you still have a problem with water getting into the intake. The reason it runs for a short amount of time, is the plugs are dry. It stalls out because the water is being pulled from the intake, and quenching the cylinders, and thus coating the plugs. Do you have access to a cooling system pressure tester? Pressure test the cooling system and see if it holds pressure. The consequence of doing this, is that you may create a hydrolock condition again. I am almost certain, that with the condition that you are describing, you have a failed upper intake, it has a hole in it. It is not too much trouble to remove the upper intake, remove it and look for water on the top of the lower intake. I went through this same situation with the Oldsmobile that I referenced in the first post. I replaced plugs as well, only to have them foul shortly after.
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Saturday, August 6th, 2011 AT 2:18 AM

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