Cloud of white smoke and burning plastic smell from under the hood

Hi folks,

I have an 81 Eldorado with the 5.7L diesel engine. I had just gotten off the highway, and was going up a hill when I noticed a large cloud of white smoke coming out from under the hood on the left side. It smelled like burning plastic. I immediately pulled over and had the car towed back to my house.

What do you think could have caused this? I have heard this car is prone to head gasket failure, but could that cause white smoke to billow out from under the hood? I have started up the car since then and just let it run (for about 5 minutes), and no further smoke.

I have checked the oil, and it was black. No milkshake looking sludge, which I have heard is an indication of head gasket failure.

Anything else I could check to see if it's a head gasket?

I was thinking it could possibly be burning power steering fluid, but I didn't find any obvious leaks or any way the burning could have occurred.

Another issue is that the dash lights have burned out, so I have no gauges to go by. However, I am quite handy with a multimeter, so if anyone can tell me where the sensors are and how to measure them directly...simple resistive sensors perhaps?

Finally, I noticed that my car alarm speaker had dislodged from the chassis, and was laying on the battery close to the chassis and + terminal. I am guessing that it is possible that the speaker mounting bracket could have made contact between the + terminal and the chassis, but could that short have caused a large plume of white smoke somehow?

Thanks!!

The mounting bracket for the siren shorting could have caused the white smoke and smell if it started to melt the siren itself (plastic), but that should be pretty obvious since there was enough smoke for you to notice while driving.

Since I couldn't smell it myself, it's going to be difficult over the forum to determine if it was an oil smell, a plastic smell, a coolant smell, or a rubber smell. Plastic is often petroleum based too so it can smell a bit like oil when burning....

Are any of the levels low - coolant or oil? It could be a bypass or other hose on the water pump that springs a leak when hot. When you pulled off the road and presumably shut off the car did the smoke dissipate quickly, or keep going for a bit? If it kept going, I'd be focusing on a cooling system issue (leaking hose). A cooling system pressure tester may make finding such a leak easier.

If the smoke went away quickly after shutting the engine off, I'd be looking more for an oil leak or an accessory drive belt that may have been slipping due to a pulley bearing or similar. Since the car was going up a hill at the time, it would have been under a pretty heavy load. I'm not sure if the '81 Eldorado has an electric cooling fan or belt driven fan (I suspect electric since I think the engine was transversely mounted) but if belt driven, the extra load from the fan clutch could have caused the belt to slip.

-Rod

Coolant and oil levels are both good.

When I pulled over, I didn't take notice of how fast the cloud dissipated, but I fairly certain the cloud dissipated quickly.

I just recently had all my drive belts tightened at a shop, so there shouldn't be any slippage there. So oil leak perhaps?

Or perhaps power steering system leak?

If I eventually want to replace the engine (olds 350) with something nicer and more reliable (cummins?) what sort of engine would you recommend? Price range is 5-10k. (down the road though)

The general rule of thumb when it comes to burning common automotive fluids is coolant will produce a white steam cloud, oil will produce a bluish gray smoke cloud. There's definitely a different smell between the two - oil will smell like, well, burning oil. Coolant will have a sweeter smell to the steam.

Since the belts were recently tightened, I wouldn't rule them out. They may have not been tightened properly, or maybe a slightly worn bearing is now very worn due to having more stress on it from the tighter belt.

-Rod

Please Help!! I just parked my car and there is white smoke under the hood. The temperature is staying the same. My biggest concern is that I have to drive 63 miles to get home. Can I drive it like this? Thank you.

There's really no way to answer your question with the information provided. Generically, NO, your car is not safe to drive this way. If the white "smoke" is burning coolant, you will likely overheat the engine if you try to drive 63 miles home. If the smoke is actually oil burning, then the car might make it 63 miles, but the burning oil could also set your car on fire, not to mention the bad smell that will likely fill the cabin of your car. If the leak is bad enough, then you could leak enough oil from the crankcase to cause the engine to overheat and/or seize up.

If the smoke is due to insulation burning on a wire or wire bundle, then there will be one or more electrical systems that won't be working correctly which may or may not be critical to driving the car 63 miles.

Without knowing what the source of the "smoke" is, there's not way to let you know if the car is safe to drive or not.

-Rod

Please look at your inbox

In the interest of keeping this thread useful for future readers, I've pasted in our PM conversation.
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Quote:
Originally Posted by pdietrich
Hi Rod. I just checked my car and there is no anti-freeze in it. Can I fill it with water, until I get home?

Tricia [/Quote]

You can put water in it, but for it to have evaporated that quickly, you have a sizeable leak and you'll need to be stopping every few miles to add more water to it. And once the engine is hot enough to turn the water to steam, it becomes unsafe to open the pressure cap to add more water. Your best bet would be to find someone who knows a bit about cars and have them inspect under the hood to see if they can determine the source of the leak. Maybe you'll get lucky and it will just be a loose hose clamp.

-Rod