Chevy impala white smoke under hood

chevrolet

#1

My check engine light has come on, and I have white smoke coming from under my hood when I drive. I’m trying to diagnose this and fix it. My mechanic had my car for a whole day and told me he needed more time to find out what it is.

My car is a 2002 chevy impala, and the smoke only comes after about 10 minutes of driving, and only lasts for about five minutes. When I open my hood, it seems the smoke is coming from the right side of my engine, maybe underneath, but it’s hard to tell, but when I look just below the right side of the engine it does look to be a little bit wet down there. The smoke has a kind of sweet smell. So far, the car is still running fine.

The smoke only comes the first time I drive my car for the day.


#2

Any ideas?


#3

I just had white smoke recently come from under my car’s hood. As far as I could tell after immediately lifting the hood upon seeing it, was that it is from a coolant leak. In my case, it appears to be coming from where the radiator hose is clamped to the thermostat housing.


#4

Rather than smoke, I suspect that you are seeing steam, and the sweet smell would seem to confirm that.

Because coolant has a sweet-ish smell (and a sweet taste, which is why this toxic substance has to be kept away from animals), I am almost certain that you have a small amount of seepage from the cooling system, and that what you are seeing and smelling is steam from that system. The easiest way to confirm my theory is by checking the level of the coolant in your radiator. (Just be sure to open the radiator cap when the engine is COLD!) If the radiator is not full, that would likely confirm that there is a leak from somewhere in the cooling system.

If the “smoke” is coming from the bottom of the engine, then one possibility is that one of the freeze plugs in the engine block has been perforated by rust. If you don’t take care of this situation very quickly, you will likely run the cooling system dry, and you could wind up frying your engine very rapidly when it overheats.

There are other possibilities, of course, but I really think that you need a new mechanic. This is not something that should be very complex to diagnose, and that statement about needing more time to figure out the problem points toward a mechanic who is either not very skilled or is not very interested in helping you.

Edited to add:
If it turns out that you have a coolant leak from a rusted-out freeze plug, that is an indication that the coolant has not been changed every few years, as it should be, and that the cooling system is likely filled with rust and other residue. In a situation like that, in addition to replacing the freeze plug, you will need to have the cooling system flushed before adding fresh coolant in the correct ratio. And then, you will need to remember to change the coolant every 3 years.


#5

The sweet smell and “white smoke” suggests a coolent leak. When it only occurs only after 10 minutes of driving further suggests a leak from a hose clamp or head gasket. After the engine cools down, a small opening allows coolant to leak out. When the engine warms up (in about 10 minutes) the expanding metal closes the leak. It would appear that the leak is dripping on a hot manifold or exhaust pipe, creating the steam.


#6

I agree with the previous posters.
If you have a hard time tracing the leak, there’s stuff at the parts store that you can add that will leave a trace that’ll light up under a blacklight (UV light). It can make finding the leak easier.

Post back with what you find. We do care.


#7

Thanks everyone for your insight. I have found out it is just as you all have said–a coolant leak. I added coolant yesterday then drove it around for the whole day. This morning I checked the tank and I had definitely lost coolant. Good news is I was able to find the leak. I wasn’t able to get my hands on a pressure checker or anything else, but I just started up my car and looked under the hood as the engine began to warm up. After about five minutes, I saw liquid dripping down. Lucky for me, the leak was in a pretty obvious spot. I know nothing about cars so I’m trying to post a picture that shows the hose it’s leaking from.


#8

It’s leaking right where that hose attaches to the engine, I saw the liquid dropping down then hitting something below and creating the steam.


#9

Easy fix. Tighten the clamp and go on.


#10

Tightened it, but still dripping. I think I’ll loosen it all the way and pull it out and push it all the way back on, then tighten it really good. Could this be a reason for my check engine light to be on?


#11

Could be low on fluid and that is what it sensed. The code would have to be read. You can get it read at Autozone or Advance for free. If it still leaks you may need a new hose.


#12

Remove the shroud and see what’s there. My guess is that the heater core hose and perhaps the T-stat housing are located there. Once you get a better look at it you’ll better be able to tell exactly what needs fixin’. Perhaps a gasket needs replacing.


#13

My guess: leaking intake manifold gasket. That could also explain the “Check Engine” light, too.