Avoid Getting Ripped Off - What is a Blown Head Gasket, Leaking Valve Cover Gasket, How to tell

[Music] everyone local beach garage well this is another video in this series on how not to get ripped off when you need to get your car fixed so you have a problem with your car and somehow it ends up at a dealership or a mechanic's told whatever you drove it there if you're having problems or you went for an inspection whatever and they come out and say the dred it works to you oh you have a blown head gasket you need new head gaskets the question is how do they know you have a blown head gasket and do you really need one in order to ask those questions it's important for you to understand what a head gasket is what it does what are the possible symptoms so when they tell you what's happening you will know whether or not that symptom is a head gasket and finally what's the difference between a head gasket and a valve cover gasket knowing these simple things will help you when you go to your car fixed to know whether or not they're telling you the truth so let's get started all right so let's talk about the basics of what's inside the engine then we can talk about the head gasket the cylinder head and your valve cover gasket whether you have a four cylinder like this would be a four cylinder here but this is actually v8 because there's another cylinder down here they're all the internals are gonna be very very similar you're gonna have pistons the block the cylinder head and the gasket between them now this is what happens you have the air and the gasoline or whatever goes into the cylinder and as the cylinder head I'm sorry as the piston as the piston comes to the top like this when it gets to the top the spark plug fires the gas and the air burn and as that expands that's what pushes the piston down in the combustion chamber or in the in the cylinder here that's what pushes the piston down that's what makes your crankshaft rotate and cause your wheel a drive through the transmission then when the piston comes back up after rotation this is what pushes out all the exec of the exhaust gasses so all the exhaust gas comes up the top it goes out your exhaust and ya'll exhaust manifold out your exhaust pipe all the way out to the backyard car so that's how the inside of the engine works and in a very basic basic form now you have the cylinder block you have your pistons and if you notice there's these little passageways in here and this is where your antifreeze or your coolant flows the coolant flows through these passageways into the cylinder head it returns and it goes back to your radiator cools down comes back to your water pump it pumps through so coolant is always being pumped through your engine that's what keeps it cool so you have this part of your engine which is all the heat and the combustion where all the action happens then you have to put your cylinder head on before you put your cylinder head on you have to have a head gasket and this is what a head gasket looks like they're all very very similar they may be different colors it may be all metal there may be different you might have a five cylinder or six alone or whatever but they're all very similar and what the head gasket does is it seals the block between the block and the cylinder head so that's what a head gasket does it seals between the block and the cylinder head that's not all it does though if you notice these coolant passages are large but the hole that mates up with the passageway here the slot here and the head gasket is not as large it's a different shape that restricts the coolant flow because you don't want too much cool and flow through because you'll cool the cylinder head faster than the block and that will cause a problem with the second reason you have a gasket the head gasket also accounts for difference in expansion if you have a cast-iron block with an aluminum cylinder head the aluminum cylinder head is going to expand at a different rate and it's going it could potentially cause a leak and you don't want to leak so the gasket also accounts for leakage and expansion it also accounts for any unevenness so if you look at the the block here the the machine marks if there's a little nick in there or on the cylinder head if there's little perfection the gasket makes up for those little imperfections that's the only thing that the head gasket does now if you can imagine you have all these cylinders here they're firing a gas an air burning in here and you got heat here and get pretty hot at higher rpm so you get up to 1,100 degrees up here so when you have a head gasket on here what can happen is the area between these cylinder walls can start to wear and between the cylinder walls if it eats way here one cylinder can leak in the other cylinder and if that happens the failure mode is the engine will run real rough you'll have trouble you'll probably get an error code Check Engine something will happen that's when you have a head gasket failure that's leaking from one similar to the other okay the next way can leak is it can blow a head gasket right out the side so it can leak from the combustion chamber to the outside of the engine it might leak into the top bottom but if that happens where there's a let's say we're to leak right here if this head gasket were to leak right here you would see exhaust gasses all around this side of the engine so if someone says you have a blown head gasket and it's leaking to the outside you better look for all that burnt or black soot around where the gasket would be leaking the other way that head gasket can leak it can leak from the combustion chamber into the coolant passage okay so you have cool of the combustion chamber here of the cylinder and here's a coolant passage over time some antifreeze or some coolant can become acidic and when that happens it can slowly eat away at this metal ring in here and eat through the paper and start to leak into the coolant when that happens that's when you start to have coolant you're getting in your cylinder it'll get in here and burn you'll have white smoke on your tail pipe or oil from the cylinder will get in your oil and your coolant will start to turn milky brown it will look real milky so that's how you know you're still it's the cylinder head gasket is leaking from the combustion chamber into your coolant okay and finally if the head gasket blows it can leak internally to the engine but regarde of where it blows and where it's leaking you'll have different symptoms the easiest one obviously is if it's leaking from the cylinder combustion chamber into the coolant passage you're gonna have either milky fluid you're gonna have milky oil in the bottom of the engine because the coolant will get in here and get into your oil that you oil be milky you'll have milky coolant or when you when the engine is running the overflow tank inside your car engine compartment will be bubbling there the pressure inside these cylinders can get up to 150 160 psi a lot of pressure so as that pressure comes up here it's going to force its way into the coolant system and the coolant system is only supposed to be around 8 to 15 pounds so the pressure goes in here it pressurizes your coolant system and when you open up the cylinder or when you open up your hood you look in the engine compartment you see bubbling and your coolant and you think the engine is overheating but that's not what's happening what's happening as your coolant is being pressurized causing it to bubble okay so now we have a head gasket there that's how you know how the head gasket is really leaking now if you have mostly most likely if you have a newer engine with fuel injection and if the if you want an easy way to check is to just take out having to take out the thermostat and they can drain the coolant and you can start the engine for a couple seconds and you can smell around where the thermostat is and then the intake manifold and if you smell gasoline or if you smell exhaust anything like that then you know the head gasket is blown it's leaking from the combustion chamber into the coolant passage if it's leaking to the outside you look for the black suck if it's leaking from one to the other you do a leak test and what they can do is they can put in the cylinder head where the spark plugs are you can put a gauge in there pump this up full of pressure and see if it leaks if it's if it doesn't leaking from one similar to another is it leaking out the side or is it not leaking at all so it's they can do some it's called a leak down test so if they say you have a blown head gasket ask them to say where is it blown how is it how is it blowing is it leaking from the combustion to the coolant is it leaking to the outside or is a cylinder to sell either way they should be able to do something called a leak down test and that's when they hook up a pressure gauge to the spark plug hole they've turned the engine over several several times and they see how much pressure can be held inside of a combustion chamber okay now we have our gasket here and on top of that is a solder net cylinder heads are pretty heavy and here's our cylinder head now the cylinder head sits under you can see why it's called a head gasket it goes between the cylinder head and the block blow and head yeah so you're gonna see it all over the place okay and here's your cylinder head this or all the valves are these this is where the intake comes in so your fuel and air coming here goes in through the valve gets burnt and then it comes out the other side to the exhaust on top here is where your oil lubricates the valves and the stems and the seal so you get lubrication up here when you take the valve cover off all you've seen here is oil if you take the valve cover off and you see coolant in here then you might have a blown head gasket or you could have a cracked head there's a lot of ways to check to see what it really is but at least we know what we're looking for with a head gasket here's your cylinder head on top of your cylinder head will be a valve cover gasket very similar to this one and these just sit on top and the only thing this gasket does is seals oil from leaking in a cylinder head to the outside of the engine so if you open your hood and you look at the valve cover and here's the valve cover is called a valve cover simply because it covers the valves the valve cover goes on top just like this if you take the if you go into the shop and if they take off the valve cover and you see coolant in there there's a problem okay if the valve cover is sitting here and you see engine oil just dripping down or dripping down around the outside of the valve cover all you really need to do in that case is change your valve cover gasket that's a very easy job it shouldn't take that month much maybe depending on where you go my only take 2530 dollars sometimes they are expensive it can be 50 60 bucks to get a valve cover gasket change but that's what a valve cover gasket is you take the valve cover off then you see your valve cover gasket there and it's been a good shape that's not leaking you're good there then you can ask them to take off the cylinder head and when they take off the cylinder head you can look inside you can look inside and just take a look at the gasket and have them show you where it's leaking if it's not leaking anywhere if there's no evidence of it leaking if they can't show you where it's leaking you did not need a head gasket okay very basics cylinders block head gasket cylinder head goes on top then we have our valve cover gasket like that and then our valve cover very simple so there you have it now you know what kind of questions to ask if someone says you have a blown head gasket ask them to show you your they're gonna have milky white oil the oil will be milky they'll be oil in the coolant the coolant we brown or they'll be leaking somewhere there should be a burnt mark on the outside of the engine or you should really push them to do a leak down test to show you that one cylinder is leaking into the other cylinders it's it's it's not that difficult and I hope I was able to show you what the parts do at least you understand what's going on in there so if you do have to question someone you're speaking with a little bit of knowledge and a little confidence so you don't get ripped off for a cylinder head gasket because it can cost $1,200 to change the cylinder head gasket maybe even more depending on the vehicle set of head gaskets might cause 1,500 $1,800 maybe up to 2,000 depending on the vehicle so you want to make sure that they're telling you the truth and that you know and you get to see the failure before you let them do the work I hope that helps you and I have a lot more tips coming up so stick around stay tuned subscribe click on the subscribe button so you can get a notification click on that little bell and you'll get a notification every time I upload a video to help you not get ripped off thanks for stopping by Pete's garage

Channel: Pete's Garage

Views: 2,229,702

Keywords: blown head gasket, how to tell, valve cover gasket, leaking head gasket, symptoms of blown head gasket, how to test for a blown head gasket, summit racing, jegs, mechanic tips, avoid car rip off

Id: jBidX6le0qQ

Length: 13min 8sec (788 seconds)

Published: Sat Dec 29 2018