Smoking '91

[Bama92]

Hey guys I'm new here and I need some help. So I have a 91 silverado with a 350 small block in it and it is smoking bad. Its white smoke and it has a sweet smell to it. I've heard two explanations for this. It could either be leaking/blown head gasket, or somehow ATF gettin sucked up from some where and burned but i don't have any idea how to check that. Any help would be greatly appreciated.

 

[PlayingWithTBI]

Generally water gives you white smoke, oil gives you blue smoke. Are you losing coolant?

 

[Bama92]

Generally water gives you white smoke, oil gives you blue smoke. Are you losing coolant?

I believe I am. And I've tried blue devil block sealer that was recommended by a few people but it didn't seem to work so I'm assuming its a bigger problem than I originally anticipated. So what the best way to fix this??

 

[df2x4]

And I've tried blue devil block sealer that was recommended by a few people

Unfortunately you've probably made the problem worse than it needed to be by doing that. All those stop-leak in a can products solidify inside the engine and cooling system and clog everything up. IMO they should only be used as a last resort on a vehicle that you know is destined for the scrap yard and just need it to last another month. I'd never put that stuff in a vehicle I cared about.

 

[evilunclegrimace]

It could also be eating coolant from a leaking intake gasket. Put a pressure tester on the rad and see if it builds pressure quickly and or builds excessive pressure. Those are signs of a head gasket leaking into the water jacket.

Another possibility is a cracked head or loose exhaust valve seat ,either of these can allow coolant into the combustion chamber and cause white smoke/sweet exhaust smell.

Unless you have a THM400 you will not be sucking ATF into the system.

 

[PlayingWithTBI]

Put a pressure tester on the rad and see if it builds pressure quickly and or builds excessive pressure. Those are signs of a head gasket leaking into the water jacket.

^^^X2
You can also do a compression check and then a leak down test.

 

[Bama92]

Awesome guys I really appreciate the help. I have a few things to check that should keep me busy for a while.

 

[SHRT 1]

Pull the plugs, pressurize the cooling system for a couple of hours - have someone crank it over & look for coolant coming out of the plug holes.