1996 gt 4.6 no compression #3 cylinder
08-03-2017, 07:55 PM
#1
Thread Starter
Join Date: Jul 2017
Location: MA
Posts: 24
1996 gt 4.6 no compression #3 cylinder
hello im new to forum.Hello i have a 1996 mustang gt with 4.6 ive only owned for 2 months.when i got it it had a misfire in #3 and when you got on it on the highway and let off it blows clouds of smoke.now it blows smoke after it warms up all the time and even way more when give it gas to go faster.i think it has work done to motor.i did a compression check right bank pass side 1 is 175 2 is 180 3 is 20 and then i did # 3 again and showed 0 and 4 is 180 i did a leakdown test on #3 and still shows 0.i took valve cover off to see if it had broke a spring but all is good there also.what could this be and can i do it on the car or need to take that head off.thank u for any input Jeff.....
08-03-2017, 08:13 PM
#2
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
What color is the smoke? White? its probly a head gasket thats blown.
If its thick bellowing blueish/brown smoke then it could have a hole in the piston or broken rings. Even bad scoring on the cylinder walls.
If its thick bellowing blueish/brown smoke then it could have a hole in the piston or broken rings. Even bad scoring on the cylinder walls.
Last edited by dawson1112; 08-03-2017 at 08:15 PM.
08-03-2017, 08:38 PM
#3
Thread Starter
Join Date: Jul 2017
Location: MA
Posts: 24
its using 1 quart oil in a 100 miles.not loosing antifreeze.only that #3 cylinder has no compression and did leak down with putting oil in that hole and still no compression.you think it a head gasket problem maybe?
08-03-2017, 08:42 PM
#5
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
sounds like its burning a lot of oil. probly bad rings, hole in piston, or scored cylinder wall.
08-03-2017, 11:12 PM
#6
3rd Gear Member
Join Date: Jul 2017
Location: AZ
Posts: 849
A fouled plug has no effect on cylinder compression. Hard to imagine a blown head gasket allowing zero or near zero compression. Something else is drastically wrong. An exhaust valve with a fingernail-sized notch burned away will still allow some compression pressure. A hole of any size in the piston-top should produce audible gushing noise from the oil-fill hole. Just my ideas. imp
08-04-2017, 01:12 PM
#7
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
regardless, the best course of action at this point is to pull the cylinder head for the #3 side and perform the necessary repairs based on what is found.
You should also drop the pan and inspect the rod bearing and piston skirt.
You should also drop the pan and inspect the rod bearing and piston skirt.
08-05-2017, 11:33 AM
#8
3rd Gear Member
Join Date: Feb 2013
Location: PA
Posts: 556
I'm thinking rings, even if it had a burnt valve and the valve seal was shot a Qt in a 100 miles is a lot of oil.
If there is a hole in the piston the crankcase will be pressurized and you will know just by taking the oil filler cap off it will gush air, you can have the same thing with bad rings but not as bad.
Zero pressure in cylinder = pull the head off
If there is a hole in the piston the crankcase will be pressurized and you will know just by taking the oil filler cap off it will gush air, you can have the same thing with bad rings but not as bad.
Zero pressure in cylinder = pull the head off
08-14-2017, 09:06 PM
#9
Thread Starter
Join Date: Jul 2017
Location: MA
Posts: 24
I'm thinking rings, even if it had a burnt valve and the valve seal was shot a Qt in a 100 miles is a lot of oil.
If there is a hole in the piston the crankcase will be pressurized and you will know just by taking the oil filler cap off it will gush air, you can have the same thing with bad rings but not as bad.
Zero pressure in cylinder = pull the head off
If there is a hole in the piston the crankcase will be pressurized and you will know just by taking the oil filler cap off it will gush air, you can have the same thing with bad rings but not as bad.
Zero pressure in cylinder = pull the head off