ok, basically the car will not pass smog because the mechanic said im running on "3 and a half cylinders". he told me that the compression on cylinder#4 is low. do i have any other options besides swapping in a new motor? ie. higher weight oil? additives? i cant register the car because it wont pass smog. is there some kind of a temporary registration/permit that allows me to keep driving the car while i try to get money to fix the problem? thanks.

P.S. Bigvinnie maybe you know some folks out here in the bay area that can help me out. im at daly city. thanks.

 

If i were u id just find another place, whenever i go for inspection they dont even test my motor or nething, they just have me rev up the car and what not to see if there is smoke, never tested my compression or nething like that..

 

low compression doesn't always mean you gotta replace the motor. It could be something small. A leaking valve? A head gasket? Just throwin a few things out there.

 

head gasket was just replaced a month ago. so now its either the valves or piston rings right? how can i tell wich one? the mechanic did mention something about a valve seat.

but, then again my friend just took the car there for a diagnostics and smog test, then my friend comes back to the shop to check up on the car. lo and behold the good ole mechanic sales tactics. valve cover was out, he took out the throttle body, thermostat, unplugged the injectors. now here is the Fkd up part. he wanted to charge my friend 400$ to put everything together on top of the diagnostics.... wtf. wasnt he just suppose to hook up a scan tool to the ecu? and then the mechanic tried to be cute and told my friend. "i'll tell you what, i'll give you "$400" for your car as-is" isnt it ironic how it cost $400 to put the crap together that my friend never told him to take out and offers my friend $400 for the car....

 

The only way I know of to check is that they make an adaptor you hook up to an air compressor, and it screws into the sparkplug hole. You pressureize it, then to check the valves you put your ear up to the muffler, if you hear air its the exhaust valve, if its not that you listen at the intake, if you hear air its the intake valve, if its not there, you take the oil cap off and listen/look for bubbles (that would be if you had bad rings), if its not that you take the coolant cap off and look for bubbles(that would be the head gasket went bad). (mind you, make sure the car is off and totally cooled down so you dont shoot hot coolant on yourself)


(hehe, I'm finally putting what I learn in auto shop to good use!)

 

I know we used to remove the spark plug on suspected cylinder, squirt some heavier type motor oil into cylinder and if the compression come up, then that's what it is.

 

I put a can of Restore in my old neon when it was down on compression. Drove about 500 miles and tested the compression again, and it really worked. I tested it about a year later and the compression was still good. It's only about 5 bucks at walmart.

 

i'll go ahead and try this method, sounds like the cheapest alternative at the moment. thanks for the help guys.