Got a new radiator cap cuz old one's springs stuck

[phyl26]

Went down and got a new radiator cap for my 91 Toyota Tercel( I had posted threads a few months ago cuz I have a cracked block and mechanic used K&W Sealer) cuz the old one's spring was stuck. We put the new cap on, start the car and man, smoke started coming out of muffler and below block or engine going up toward hood! So, turned car off and put on old radiator cap again and damned if it didn't stop smoking like it was with new cap! It was white smoke. What could putting a new radiator cap on have to do with my car starting to smoke like that? One more strange thing. I haven't heard engine fan come on since block got the crack and sealant was used. But it came on with new radiator cap but when we put old one back on, no engine fan again! Can anyone out there shed some light on this for me? Is it putting too much pressure on something? It was really strange that an old part works better than a brand new one! You would think it would be the reverse where new part made it run better. Appreicate anything anyone can tell me as to why this would happen!

[iruka_hoshi]

That is very odd.... The only thing I can think of if that there was sealant on the old cap to and when you replaced it it broke free. When letting you car idle it should become very obviously whne the thermostate is comeing from. White smoke just meaning you are burning a good share of coolant. When using cooling system selant it's easy to gum up you systemm where you don't want it to gum up. Like in you in/outlets, cylanders and thermostat. This is how come it's so important to flush you cooling system very well before and after using one of the head gasket repair bottles of gunk. Let you totoya idle for a while, usually smoke is worst at intially start up and burns of. If you see similar white smoke coming from the engine, your head gaskets probably pretty well shot. Not at all uncommon on 3e-e engines.

[phyl26]

Yeah, our mechanic said he flushed the coolant system out very well before/ after using the block sealant. Ever since we had the system flushed and the sealant put in, at first we were running water in radiator but where we live it get to be 105 degrees in summer so we decided to start running straight coolant. At first it was using about a bottle a week but this last week, it has hardly used any coolant. I did hose our car off the night before we tried the new radiator cap and I also hosed the engine off. Could this have had anything to do with how it acted? If some sealant broke free from old radiator cap how come when we used new cap it started to smoke? It was when we put the old one back on that the car started running as usual and no smoke at all. I don't know so that is why I am asking questions. Nothing is coming out of muffler and no smoke was ever coming out until trying new radiator cap. Just had to use straight coolant and thermostat works cuz when I drive it around town with the stop and go it starts to get a little hot but on freeway it stays right were it always did before the block got the crack in it. Thanks for trying to help/ appreciate it!