I had the head gasket go out on my 5.8 liter v8. The local ford dealer replaced them for me. They told me it was running like a top and they drove it about 3 blocks and it died. They popped the hood and the passenger side exhaust manifold was glowing red hot. It had burnt the plug wires in two. They told me it had a clogged Catalytic converter. I disconnected the muffler/converter and drilled it full of holes to insure airflow. I replaced the plug wires and attempted to drive it to a muffler shop 8 blocks away. The motor would run but would not rev up and acted like it was towing a freight train. I wasn't able to go over 15 miles per hour. I arrived at the muffler shop to have the CAT removed and discovered the motor had burned through the plug wires again and was glowing red hot again. I have taken it to 2 mechanics and they have no idea what is wrong. I do know that it IS NOT the Cat/converter. I thought it was timing, but the mechanics assured me it is not. The back 3 cylinders on the passenger side are running about 150 degrees hotter than the other 5 cylinders. I need help. The motor has been well taken care of. It is not worn out. It was running perfectly when the gasket blew. It did not get hot. I'm not sure what would cause this. What went wrong on my gasket repair for it to have messed up so bad?
Disconnect the exhaust pipe from the exhaust manifold (2-3 bolts) to see if you are getting a lot of exhaust out there when the engine is running. I'm thinking that the blockage [if there is one] could be in the exhaust manidolf itself.
If this is too muh trouble [and causes too much noise - running disconnected like that] you can unbolt the exhaust manifold from the engine and use compressed air to blow through each exhaust manifold tube to check for blockages.
If all of this is OK [or while you're doing the other checks], check the three injectors which supply fuel to the 3 cylinders which are runnig hotter than the others tosee if they are leaking 9excess gas could be burning in the exhaust manifold causing then to burn cherry red.
July, 7, 2013 AT 9:01 PM
Would it not run normally at first even if it has a manifold blockage? It won't run right and it is getting about 6 mpg. I went from 14 to 6 just from a head gasket job. I think I better reinstall a CAT. But I know the cat isn't the root of the problem. I'll try disconnecting the manifold. I'll let you know how it goes, as soon as I do. Thanks.
July, 8, 2013 AT 8:45 AM
How long has it been since the dealership did the work?
If the work is still under warranty, please take it back and demand that they get it right! Regardless of their opinion, it is clear that they did something wrong, so why should you have to pay for it (either in money or aggravation)?
July, 9, 2013 AT 3:03 PM
Does the engine idle normal? is there black smoke coming out of the exhaust pipe?, It could be a faulty EGR valve or a fuel pressure regulator with the diaphragm blown. Please remove the vacuum line from the regulator to see if there is fuel present. please visit this link for reference.
Also, remove the spark plugs from the cylinders in question to see what they look like?
Get back to us, we want to help, thanks for the donation, the site can use it :-)
July, 9, 2013 AT 6:52 PM
It does not idle normally. The exhaust is clear. The plugs appear to be normal. The IDle air control and pressure regulator have been checked. The timing was checked and I was told it was a little off but not enough to cause this number of problems.
I have been told the gasket may have been installed upside down and could be blocking the water ports. It would explain the heat but not the mileage and poor idle. It races and slows down. I am tracing the vacuum lines. I was also told the intake gasket may have been creased and it could be sucking air. The last mechanic said the motor was just worn out and showing it's age. That is a load of BS. He couldn't figure it out. I know it went from 14MPG and running perfectly to a blown head gasket. It didn't get worn out while sitting in the dealer shop waiting to be repaired. I know this is a tough one. I appreciate the help. Never seen anything like this.
July, 9, 2013 AT 7:14 PM
This is a weird problem, it could be an intake gasket failure, that would cause the problems you are describing. Could the firing order be off? Doesn't seem right since it ran great then stalled. Easy check though.
Firing Order. It is 1-3-7-2-6-5-4-8 and the cylinders are numbered 1-2-3-4 front to rear on the passenger side and 5-6-7-8 on the drivers side.
IF okay, can you take the coil wire off and ground it, next crank the engine over to see if it sounds normal to you.