I have a 1988 ford motorhome with a 460 motor. We bought it 3 years ago, and the first time we had it out it worked fine. Before taking it out the next, I checked the antifreeze and found it down. There were no signs a leak any where so i topped it up. I went to fill it up with gas, and noticed fluid leaking on the ground. It was antifreeze which was leaking out of the radiator from too much pressure. I found that it stopped building up pressure when it reached the same level it was before, and hasn't leaked again. Since then I have been having a problem with a bad smell and smoke coming from the manifold and exhaust pipe near the engine. I have had to 3 mechanics and spent lots of money with no cure. The motor works beautifully, but when under load, like going up a hill or facing a bad head wind, the smell is always there. Almost like rotten eggs. Any suggestions.
When referring to the antifreeze leak, the system should be filled up to the required level and then a pressure test should be performed. The pressure test will simulate the engine running and you can look for the leak more safely. Carefully look at the suspected leak areas to confirm any leak.
Another way to check for a leak is to add a dye to the antifreeze, then run the engine in a normal manner. When the test drive is complete you need an ultraviolet light to look for the leak. When a leak is found it will show up as bright lime green color which is very obvious.
How is the engine running?
Does it seem to have a lack of power or like you are towing a trailer?
Is the engine overheating, or dripping coolant on the exhaust system somewhere?
Is the engine blowing out a white steamy smoke out of the tail pipe?
One cause could be a leaking head gasket. This can cause a bad smell like you describe. To check a bad head gasket, pressure test the cooling system again, remove all the spark plugs and wait about ten minutes. Then crank the engine over with the spark plugs removed, if a bad head gasket shows, it will blow antifreeze out of the cylinder(s) that are bad.
The rotten egg smell could also be that the engine is running a rich fuel mixture; it may have the ignition timing improperly set, a clogged fuel filter, clogged exhaust system (catalytic converter). All of these symptoms can cause you to push on the gas pedal further than needed to keep up the speed you are trying to achieve, which can cause a rotten egg smell.
Checking all of these symptoms and correcting the problems can help clear up the rotten egg smell.