Last post on Jan 25, 2013 at 11:52 AM
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Pontiac Bonneville, Sedan
#1347 of 2268 Loud ticking and check engine light
Sep 22, 2004 (7:27 am)
I have a 1996 pontiac bonneville Se with 178303 miles. I been losing coolant about a half gallon every 4 days unknown if head gasket leak or dripping it out. The only drips i've seen is on the bottom of the back firewall where A/C condensation comes out but seems like a lot more then normal and not the red dexcool color.I cleaned the engine with Gunk engine cleaner and water hose the next day I had my check engine light come on which I was told was a code for Misfire cyclinder#6 and a loud ticking(like fuel injector but very loud). My mechanic thinks its a collapse lifter. As the engine was running the ticking stopped but engine light still on.I changed the #6 coil pack and engine light went off.Help any Ideas will be appreaciated,thanks.
Sep 23, 2004 (1:09 am)
Pull the plugs and inspect for signs of coolant contamination. The upper intake plenum is probably warped in the EGR tube area, allowing coolant to enter the intake.
Sep 23, 2004 (2:39 am)
What are the signs on plugs of coolant (Dexcool) contamination? What should I look for when I change my own plugs?
Sep 24, 2004 (3:16 am)
White deposits on the spark plug electrodes, electrodes wet or very clean looking. Also, crank the engine over with the plugs out and look for any coolant or vapour coming out of the plug holes. We do that with a cooling system pressure tester installed, which will force coolant past leaks and into the cylinders.
#1351 of 2268 96 bonneville not starting
Oct 02, 2004 (1:45 pm)
I have a 96 bonneville with 93k miles on it. And I drove to the mall in it but, when I came out to go home it would not start. The radio worked, but when I turned the key it did nothing. So I went to sears in the mall and bought a battery. Installed it, both of the screws were nice and tight, but it still would not start, it did the exact same thing. And help would be greatly appreciated.
#1352 of 2268 Intake plenum and /or headgasket??
Oct 02, 2004 (9:45 pm)
Regarding post#1347-1350 I like to know if pulling plug and inspect for signs of coolant contamination. How will i know if i need intake plenum and/or head gasket? How can i determine if i need either one or both? when i turn key it cranks but takes a few seconds to run. I use a full gallon on one way 45 mile trip. No signs of leaks. when car idles it leaves one foot round wet spot but no white smoke. also when stop at light feels like it wants to stall and sputters. check engine light on steady and sometimes blinks, also traction off light goes on and off at times. Please alcan or anybody any help is appreciated,thanks. oil pressure at idle about 40-50.
Oct 03, 2004 (2:10 am)
If the coolant level is dropping in the overflow tank but there are no external leaks, it has to be going somewhere and that somewhere is usually through a warped upper intake plenum. I've already posted how to check for this condition. Head gasket failures with 3800's are rare.
1 full gallon of fuel for 45 miles = 45 m.p.g., very impressive gas mileage.
The wet area is probably air conditioning condensate, normal.
For the hard start, locate and remove the vacuum hose attached to the fuel pressure regulator. If there's any evidence of gas in the hose, replace the regulator.
If the check engine light is on have it scanned at any AutoZone (no charge) and post back with the stored trouble codes.
Oct 03, 2004 (4:23 am)
Did the dash warning lights stay on after you put the key in -- specifically did the 'security' light stay one. That means the key resistor wasn't being read right. It stays on for three minutes if you try turning the key 3 times and the resistor is wrong. After 3 minutes with a working resistor you can start the car.
Do you have a second key? Try it -- if the security light on the dash is staying on. I had a problem a few times with dirt, lint, goop, on the resistor contacts not letting the reading be correct. Cleaning with pencil eraser works. But I had to try my second key.
I also had the wire to the lock cylinder start breaking strands from flexing the tilt wheel up and down. That caused the light to go on but the car still started. If the wire breaks too many strands the resistor reading to far off and the car won't start because it thinks it's being stolen.
#1355 of 2268 correction to Intake plenum and /or headgasket
Oct 03, 2004 (9:04 am)
1 gallon of antifreeze/water not fuel. the one foot round water spot is from the exhaust pipe(tail pipe). sorry i wasn't clear before. hope this helps you help me with more ideas. thanks Alcan(your an asset to the forum) and all.
Oct 04, 2004 (2:43 am)
First, pick up a block and head check kit from any parts store. It checks for the presence of hydrocarbons (fuel) in the radiator. If so, a head gasket is blown or a head's cracked. Neither is likely.
Next, remove the spark plugs and inspect them as mentioned previously, install a cooling system pressure tester on the radiator and leave it pumped up for a few minutes, unplug the wiring harness from the ignition module, crank the engine over, look for any coolant mist coming out of the plug holes. Probably #4 and #6, rear bank driver's side. Would probably also account for the check engine light, usually code P0300, random multiple engine misfire.
The throttle body, which attaches to the upper intake plenum, has coolant passages around it to promote cold weather driveability and throttle response. The coolant passages are between the lower intake manifold and upper plenum. The EGR (exhaust gas recirculation) tube is also right there, and heat from the exhaust gases degrades and warps the plenum over time. A slight gap develops between the manifold and plenum, coolant starts leaking into the manifold, and you now have an engine which consumes coolant.
Keep driving it like that and you'll discover either A: coolant doesn't compress in cylinders and you have a bent connecting rod or wiped out rod bearing, or B: none of the engine bearings like being lubricated with coolant. Either way, you'll be looking for a replacement engine or scrapping the car if you don't get it corrected.