Failed smog

Tiny
NICKOLA
  • MEMBER
  • 1998 CHEVROLET CAMARO
  • 3.3L
  • 6 CYL
  • 98,000 MILES
Mechanic says blown head gasket as there is a misfire number three cylinder. It runs rough at idle, but on freeway runs great. It does not use any water so I do not think it is head gasket, but a vacuum leak. Changed MAP sensor, coolant temperature sensor, plugged off EVAP purge solenoid. Service engine soon light comes on and goes off a day later, then back on again, and a day later off.

Any ideas? Mechanic said number three 51psi.
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Friday, May 18th, 2018 AT 4:11 PM

6 Replies

Tiny
JOHNNY G.JR
  • MEMBER
Have mechanic do a cylinder leak down test to verify issue, 51 psi is extremely low.
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Friday, May 18th, 2018 AT 4:15 PM
Tiny
NICKOLA
  • MEMBER
At 150 a pop each time I see a mechanic I can buy a newer vehicle. I already have over $699.00 into this. Question is: would a vehicle with 51 psi in $3 cyl on a Chevrolet 3800 V6 cruise at 70 mph with no problem for an hour or so? Would it not overheat or at least be low on water?
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Friday, May 18th, 2018 AT 6:00 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi and thanks for using 2CarPros.com. Based on your post, I would say it could. However, other issues will result. First, if there are no coolant leaks, including head gasket issues, coolant will not be low. A head gasket does not always mean there is a coolant loss. It could be just a compression leak. Most parts stores will lend you the compression gauge. Try it yourself to determine if compression is actually the issue,.

Here is a general video showing how one is done:
https://youtu.be/J3j85hg0d-4

Additionally, here are directions to help determine if a head gasket is bad.
https://www.2carpros.com/articles/head-gasket-blown-test

Here are the directions specific to your vehicle to check compression. You will need a compression gauge. Most parts stores will lend you the compression gauge. Try it yourself to determine if compression is actually the issue,.

COMPRESSION TEST

Tools Required
J38722 Compression Tester
A compression pressure test of the engine cylinders determines the condition of the rings, the valves, and the head gasket.

Run the engine until it reaches normal operating temperature. The battery must be at or near full charge.
Turn the engine OFF.
IMPORTANT: Remove the Powertrain Control Module(PCM) and the ignition fuses from the I/P fuse block.

Disable the ignition.
Disable the fuel systems.
Remove the spark plugs from all the cylinders.
Remove the air duct from the throttle body.
Block the throttle plate in the open position.
Measure the engine compression, using the following procedure:
8.1. Firmly install the compression gauge to the spark plug hole.
8.2. Have an assistant crank the engine through at least four compression strokes in the testing cylinder.
8.3. Check and record the readings on the gauge at each stroke.
8.4. Disconnect the gauge.
8.5. Repeat the compression test for each cylinder.
Record the compression readings from all of the cylinders.
The lowest reading should not be less than 70 percent of the highest reading.
No cylinder reading should be less than 689 kPa (100 psi) .
The following are examples of the possible measurements:
When the compression measurement is normal, the compression builds up quickly and evenly to the specified compression on each cylinder.
When the compression is low on the first stroke and tends to build up on the following strokes, but does not reach the normal compression, or if the compression improves considerably with the addition of three squirts of oil, the piston rings may be the cause.
When the compression is low on the first stroke and does not build up in the following strokes, or the addition of oil does not affect the compression, the valves may be the cause.
When the compression is low on two adjacent cylinders, or coolant is present in the crankcase, the head gasket may be the cause.
Remove the block from the throttle plate.
Install the air duct to the throttle body.
Install the spark plugs.
Install the Powertrain Control Module (PCM) fuse.
Install the ignition fuse to the I/P fuse block.

I hope this helps answer your questions.

Take care,
Joe
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Friday, May 18th, 2018 AT 10:14 PM
Tiny
NICKOLA
  • MEMBER
Thank you very much.
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Saturday, May 19th, 2018 AT 9:51 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Glad to help. Let me know if you have other questions or need more information. We are here to help.

Take care,
Joe
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Saturday, May 19th, 2018 AT 7:55 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Wow! I appreciate that.

Take care of yourself, Nick, and I hope you get the car problems resolved.

Joe
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Saturday, May 19th, 2018 AT 10:50 PM

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