2002 Buick LeSabre radiator cap came off  and car overheated.Pulled over immediately but saw the steam coming from between bottom of valve ?

cover where it mates with the manifold it looks like to me, (as a non expert). On the front of the engine. Does this indicate a blown head gasket necessarily? The valve cover gasket was leaking oil before that. But I’m just wondering if it’s a blown head gasket now. Pulled the car over and waited a full hour until filling it up with some antifreeze I had. And then going and getting more distilled water and adding more antifreeze.

Update:

Thanks for these answers. I guess you guys Figured out what I was talking about. I’m not sure I was getting my technical terms right with the valve cover mating  with the manifold, etc. But yeah the smoke (steam?) it was definitely coming from where the top of intake manifold where it meets with whatever that component is directly above it. 

7 Answers

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  • 8 months ago

    Radiator caps do not just pop off. Either it wasn't put back on after looking at the coolant or it was removed intentionally. Check the radiator each morning while the engine is still cold to see if you are losing coolant. Maybe you have a leaking hose: I have to guess what your description is about. Probably the hose to your water pump has a hole in it.

  • Anonymous
    8 months ago

    I assume this is a GM 3800 engine, there is a small bypass hose that connects between the engine intake manifold and water pump that often fails. Some of the 3800 engines had a plastic nipple fitting screwed into the aluminum intake manifold that can crack with a slow steam leak. That heater bypass hose is relatively easy to replace once the alternator is removed for access to the bypass hose. If that manifold has a plastic hose nipple cracked or not at the intake manifold, replace it with a metal part and new PTFE sealer tape. Look back behind the alternator at the center of the intake manifold and you will see the hose and fitting I am referring to. That part cracked and it cost a head job with new head gaskets on one my ex owned. It is a clear example of GM saving .27 cents on a critical engine cooling system part.

    BTW, that intake manifold fitting is the same as a garden hose nipple and where you can easily connect a garden hose to flush the engine cooling system out from top to bottom. The other place they leak is at the plastic intake plenum gasket by the EGR valve tube.

  • 8 months ago

    That generation GM intake gasket is known to leak and fail because of the interaction it has with the recommended GM coolant. It isn't a huge deal to swap it out and consider yourself lucky it lasted as long as it has. New gaskets are compatible with the coolant. 

  • 8 months ago

    You probably popped the intake manifold gasket, it would have eventually failed anyway even if you hadn't over stressed it.

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  • Anonymous
    8 months ago

    Get your vehicle towed.  The car is losing coolant.  You will get a blown head gasket the second time it overheats.  Do not push your luck.

  • Anonymous
    8 months ago

    No, it doesn't indicate a blown head gasket, it just indicates that coolant fluid got onto the manifold and evaporated.

    A blown head gasket would be indicated by oil getting into coolant, and vice-versa.

  • Anonymous
    8 months ago

    um ok?           

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