so my 78 mark v is shaking when idle, also there is white smoke coming from the engine, i asked around on other websites and got different answers, some say it's a blown head gasket. some say it's a cylinder misfire. and some say my radiator is shot, what do you guys think it is?
engine is shaking when idle 78 lincoln mark V
- Thread starter carfreak
- Start date
opalescent 96
New member
It's hard to say with the limited information that you've given but I'll throw out some things.
First, check your oil; if it has a white milkshake color to it then water is getting into the oil and that's bad! That could be a head gasket or the front cover leaking into the motor. I don't believe the intake has water in it on a 400 or 460 but I could be wrong. Second (with the engine cold) check the radiator; are you low on coolant? Check these two things and tell us what you find...
Tell us more on the condition of the car... does it drive, how does it run etc. How many miles, how was it cared for, what service have you done so far etc.
If you don't drive it much and it's been sitting it could have lot's of white smoke when you start it from moisture in the exhaust and maybe it needs a full tune-up?
opalescent 96
New member
Well that's good news about the oil.
460's are good motors! How is the transmission shifting? You might have a bad transmission vacuum modulator. When they go bad the motor will start sucking in transmission fluid and that could be the smoke you are seeing.
Also how are the brakes? I had a car that would suck brake fluid from the booster but if that was the case you would know because the brakes would be very soft and low.
opalescent 96
New member
You can check the transmission vacuum modulator from under the car. It's at the back of the transmission by the pan. Pull the vacuum line off the modulator and if there is fluid in there the modulator is bad and probably the cause.
driller
El Presidente
After checking all of the above, I would give it a good maintenance check and tune up. The shaking at idle does sound like a misfire which could simply be fixed with new plugs and spark plug wires.
R&R filters, plugs, wires, and fluids; then check timing and check the vacuum lines for leaks. I would also consider running some Seafoam through the intake to clean out carbon deposits. You could also use some Seafoam or other fuel conditioner in the fuel tank to help get rid of old fuel and varnish deposits.
R&R filters, plugs, wires, and fluids; then check timing and check the vacuum lines for leaks. I would also consider running some Seafoam through the intake to clean out carbon deposits. You could also use some Seafoam or other fuel conditioner in the fuel tank to help get rid of old fuel and varnish deposits.