My samurai seems to start rough and make a 'banging' or rattling  noise. It will run fine after that, but it's burning through about a quart of oil every week. I'm inning full synthetic 10w30. I was told the oil issue could be related to the synthetic oil. I should probably also mention that he exhaust is giving off a strong odor when I downshift or take off from a stoplight. I tried putting oil treatment in the crankcase but it hasn't seemed to help much. Any ideas would be greatly appreciated.

First - try switching to a conventional 10w30 oil and see what effect it has on the oil consumption - you're not going to achieve any of the benefits of a synthetic if you're dumping it down the tail pipe at the rate you are, so you might as well save a buck or three.

Second - does the vehicle smoke any?  Like from a cold start, and yes also when you pull away from a stop light or down shift?  My suspicion is that you have leaking valve seals, a wet & dry compression test may help confirm that.

I'm going to definitely switch back to conventional oil here the next time I change the oil, and I have all intentions of having a compression test done. Ever since I bought the vehicle, the exhaust has had a very sharp and sometimes sweet odor that can be smelled when driving with the windows down. I checked the coolant level yesterday and it was full, however i did notice some bubbles on the radiator cap. I've read that this is a symptom of a blown head gasket. Are these bubbles a true indicator of a blown head gasket, and if so, could this be the cause of the mysterious vanishing oil?

Also, in comparison to my old 87 hardtop, my new Sammy seems to be much hotter in the engine compartment after running it for about 35 miles or so (one-way home from work). It made me consider the flow of coolant throughout the vehicle. I checked the top and bottom radiator hoses, and the top was scorching hot, while the bottom was cool to the touch. I understand the bottom radiator hose should be cooler, but should it be cool to the touch? Could my problem be as simple as a thermostat? Could this potential lack of coolant flow be drastically increasing the viscosity of my oil enough to cause it to seep through the seals?

Just trying to connect the dots... 

The thermostat would have to be open for the top hose to get hot - perhaps the radiator is blocked?

Good point, fordem, and thanks for your help. The thermostat is working fine. I decided to go ahead and flush the coolant and change the radiator cap yesterday since I've read that faulty radiator caps can cause similar symptoms as a faulty head gasket (such as small bubbles on the cap). I haven't had a chance to drive the vehicle since then.

I'm concerned about the color of the coolant that was in the vehicle. It had a rusty brown appearance, and appeared thin. It was almost as if it had no antifreeze mixed in at all. I guess this makes sense since I bought the car from Georgia. I then checked the oil for a "milky" appearance, but it looked to be free of any contamination. So this leads me to believe the "coolant" was just old and discolored and not oil-filled and indicative of a leaky head gasket.

Lastly, this cold start issue is starting to concern me. It seems like starting the vehicle is becoming harder each time I turn the key. Once I get it warmed up, it will start flawlessly, but when I let it sit over night it seems to slowly crank and then make an annoying "clanking" noise when it finally does fire up.



SD


PS: Still yet to do compression test. I should probably quit jacking around and just get it taken care of but I haven't found the time.

Flush your coolant system and fill with a premix 50/50 coolant(unless you have distilled water to make your own, DO NOT USE tap water!).

Sounds like you may have a battery charging issue if it is getting harder to start each succesive cold start.