hi, I have a small car which has only done 28000 kms and I bought it brand new. I have noticed it has been using more coolant than normal and it has become quite hot at one point. My mechanic went to service it and said it appeared that water was in the engine. (contamination of oil underneath the oil cap). As it is under new car warranty I took it back to the dealership. They said it was due to leaking core plugs and have replaced them. My mechanic said if it was leaking core plugs the coolant would be leaking out onto the ground not into the engine and contaminatiing the oil. Dealership said this is rubbish. I am confused and don’t know who to believe. How do I know if it has been fixed or not and how do I know if it isn’t something worse like a cracked head gasket? Can someone please help? Thanks
Make, model, year, engine option? In general, I agree with your mechanic. Coolant gets into the engine through bad seals or cracked metal. Core plugs are external, and coolant cannot get to the oil that way.
If the dealer fix doesn’t work, have them look at it again. If they still can’t fix it, you may be able to get some relief if your state has a lemon law. Research it. Key to this is to document everything, including the statements from your mechanic.
What brand, model, and engine do you have? What year is it?
GM products in the late 90s/2000s had issues with intake manifold gasket leaks which would contaminate engine oil with coolant. Coolant will displace the oil from the crank bearings and will lead to engine damage if the gasket is not replaced in a timely manner.
Cars that are only driven occasionally or short distances will show condensation or a creamy sludge under the oil filler cap due to normal condensation not being burned off. A long drive (+30 min) once a week to give the car time to fully warm up and burn off the condensation usually cures this issue. It doesn’t hurt to replace the PCV valve either.
Again, make, model, year, engine, etc information is needed for any intelligent guess.
My mechanic went to service it and said it appeared that water was in the engine. (contamination of oil underneath the oil cap).
+1 to edb1961 comments- The existence of this foamy crud on the fill cap is not necessarily definitive evidence of coolant in the oil. Many cars that experience short hops will have condensation problems that are evident at the fill cap.
How do I know if it has been fixed or not
When it stops consuming fluid, it is fixed. Have you monitored the coolant level to ensure it is not dropping anymore?
No coolant loss is normal, without knowing year make and model we are helpless to offer you sound advise. Do you live in the United States?