Cracked engine block?

If you have a cracked engine block, coolant from the water jackets can leak inside the combustion chamber, as well as leak into the oil pan. If enough coolant mixes with the oil, the oil becomes very thick and viscous, and your engine can break down, or be damaged beyond repair, costing >$1,500 in repairs. The best way to detect this is if you are running low on antifreeze/coolant. If there isn't a puddle of it beneath your engine, it must be escaping elsewhere. Probably into different areas of the engine due to cracks in the block/water jackets.

My dad's car is constantly low on antifreeze, he adds at least one quart of it into his car per month. There is no trace of antifreeze on the floor of the garage. Where is it going? Is it evaporating or leaking into the engine itself?

Coolant can clog and obstruct your exhaust valve if enough of it gets into the cylinder/combustion chamber. These very same problems can be caused by a blown head gasket. I'm not quite sure what might cause an engine block to crack or fracture.

Has anyone here had this happen to their vehicle?
15 answers Last reply
More about cracked engine block
  1. You can crack an engine block several ways, but there are some that are more common than others:

    - Running water through the cooling system instead of antifreeze in cold weather
    - Running cold water through an already hot engine
  2. Coolant can leak from the water jacket into several parts of the engine. The most common leaks are -


    Coolant into combustion chamber
    Coolant into oil galley / return (winds up in the oil pan)
    Coolant out of engine completely (puddle on ground)
    Coolant into exhaust port (crack by valve guide, leaks into exhaust system)
    Coolant into intake port (not as common, coolant gets sucked in, and burned off)


    If you check your oil and it's clean and not contaminated (coolant and oil mixed will look like a milkshake after the engine has been run) and it's not on the ground, it is most likely leaking into an exhaust passage and being burned off or into a cylinder and being burned off. Generally, if a cooling system pressurizes properly, if the leak is into a cylinder, you will experience a hydrolock situation where after the car sits after being run, a cylinder will fill with antifreeze, making starting very hard. If it's leaking into an exhaust passage, it might be unnoticeable as the coolant will pool in an exhaust manifold or a low part in the exhaust system, and simply be evaporated when the car is started and driven.
  3. if your loosing water and its not on the floor
    its a blown head gasket...........
  4. excelerater said:
    if your loosing water and its not on the floor
    its a blown head gasket...........


    Actually the only thing that would normally cause coolant to leak into the passenger compartment is a heater core... Cracked engine block would not cause this.
  5. Psychoteddy said:
    Actually the only thing that would normally cause coolant to leak into the passenger compartment is a heater core... Cracked engine block would not cause this.



    you would smell that,and have wet feet LOL
  6. If you have coolant going into the combustion chamber then you would have a lot of white steamy smoke coming out of exhaust. Also loss of compression because of blown headgasket.
  7. Common problems with rovers: Broken fuel pump - £100-300
    Blown head gasket!! - New Car!!
  8. it has happened before where a head gasket has failed and the pressure from the combustion of one or more cylinders has been piped to the cooling system as a result of the failed head gasket .if this were the case it would be forcing out coolant as you drive due to the cooling system design , chances are if this were the case it would get dumped out the overflow while you drive as the pressure would far exceed the cooling systems designed pressure range . my advice is idle this in your drive way topped off and watch the temp gauge close and wtch for the source of the loss of coolant
  9. "Milkshake" looking material on the underside of the oil filler cap indicates a mixing of oil and coolant, usually due to bad head gasket, or warpped aluminum head - but sometimes can indicate a water jacket crack
  10. ambam said:
    If you have a cracked engine block, coolant from the water jackets can leak inside the combustion chamber, as well as leak into the oil pan. If enough coolant mixes with the oil, the oil becomes very thick and viscous, and your engine can break down, or be damaged beyond repair, costing >$1,500 in repairs. The best way to detect this is if you are running low on antifreeze/coolant. If there isn't a puddle of it beneath your engine, it must be escaping elsewhere. Probably into different areas of the engine due to cracks in the block/water jackets.

    My dad's car is constantly low on antifreeze, he adds at least one quart of it into his car per month. There is no trace of antifreeze on the floor of the garage. Where is it going? Is it evaporating or leaking into the engine itself?

    Coolant can clog and obstruct your exhaust valve if enough of it gets into the cylinder/combustion chamber. These very same problems can be caused by a blown head gasket. I'm not quite sure what might cause an engine block to crack or fracture.

    Has anyone here had this happen to their vehicle?



    was just told same thing by someone who has not even looked at my car, and they were correct evn down to the price
  11. I've seen wet liners crack before or the o-rings go on them but there are very few if any gas engines that use wet liners. Everything to me is saying a cracked head or a head gasket is gone. If you cannot see a leak then look at the exhaust and oil because it has to going somewhere. If the exhaust is white then it is being burned by the engine and I would suspect a cracked head. If it was the head gasket you would notice the water jacket and radiator pressuring up because cylinder compression is higher than the pressure in the cooling system. An easy way to test this is a coolant pressure tester. Pull the rad cap off install the pressure tester and run the engine. If you see pressure rise then exhaust is entering your cooling system.
    Also what type of car is it?
  12. Coolant can leak from the water jacket into several parts of the engine.
  13. MRtech said:
    "Milkshake" looking material on the underside of the oil filler cap indicates a mixing of oil and coolant, usually due to bad head gasket, or warpped aluminum head - but sometimes can indicate a water jacket crack

    where should i repair
  14. jamspark said:
    where should i repair


    You have coolant in the oil? If so then what type of vehicle do you have because different engines have different weak spots. Realistically you're most likely going to be removing the head(s).
  15. wip99gt said:
    I've seen wet liners crack before or the o-rings go on them but there are very few if any gas engines that use wet liners. Everything to me is saying a cracked head or a head gasket is gone. If you cannot see a leak then look at the exhaust and oil because it has to going somewhere. If the exhaust is white then it is being burned by the engine and I would suspect a cracked head. If it was the head gasket you would notice the water jacket and radiator pressuring up because cylinder compression is higher than the pressure in the cooling system. An easy way to test this is a coolant pressure tester. Pull the rad cap off install the pressure tester and run the engine. If you see pressure rise then exhaust is entering your cooling system.
    Also what type of car is it?


    I have an old Nissan B12 with an 1.6 Cab engine and the water is coming up from the radiator when on idle is this because the head is crack or the cylinder head gasket is blown.
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