Up next in 10
How to Tell if Your BMW Head Gasket is Blown (and Find Coolant Leaks!)
21K views
Jan 29, 2023
In this video you will learn the process that I go through to diagnose a blown head gasket on a BMW and how I typically find coolant leaks. This particular vehicle is a BMW E36 but this process will work the same for most model BMWs. The most important tool you will need is a coolant pressure tester. These testers can typically be rented for free from a local auto parts store.
View Video Transcript
0:00
Hey, E36 fanatics, Steven here
0:02
Today I got another really cool video for you, and this one is going to be diagnosing a head gasket leak on a BMW
0:10
Now, this specific BMW is an E36, of course, but it's going to be generally applicable to a lot of different BMWs
0:17
because we all have external reservoirs. And so basically, this vehicle has been sitting for about five months
0:26
and when I first started it afterwards, it had white smoke coming out of it
0:31
and it's got a long-standing coolant link. So I just had to trash another E-36 because the engine got blown up from a bad coolant leak
0:42
that blew the head gasket. So, you know, while I'm restoring this car, I'm really worried about another blown head gasket
0:48
so I want to make sure that it doesn't have one. So I'm going to show you there's a couple different symptoms to look for with a blown
0:54
head gasket on a BMW and then after that if you still don't really have a conclusive result
0:59
and you want to make sure I do a cool and pressure test. So you're going to see that as well
1:04
and you're going to see the results of that. So I'd suggest watching this whole video because
1:09
I'm going to have a couple different things that you can do for a head gasket. So if you're
1:14
familiar with some of the symptoms of a head gasket leak, one of the most obvious ones is white smoke
1:20
coming out of the exhaust tailpipe. As you can see now, I've been driving it a
1:24
and it seems like it was just condensation in the exhaust because it is not shooting out any smoke at this point
1:31
So another really obvious sign of a head gasket leak is if you've basically got exhaust bubbles or if you've got bubbles coming up from your coolant
1:40
So basically if it's really bad exhaust gases will come back into the coolant and a lot and you can actually see the coolant bubbling
1:48
As you can see here it not bubbling So that another like obvious thing that I not seeing with this But that only happens when you have a really bad head gasket leak Another really easy way to tell if you got
2:02
a head gasket leak on a BMW or really any other cars is to take a look at the oil. As you can see here
2:08
there's no milky substance in the oil. There's no cooling in this. And I have had a blown
2:14
head gasket on a BMW where a coolant was getting in the oil. And it was really, really
2:20
obvious. Okay, so now that I've gotten out of the way, the really simple symptoms to check for
2:26
you know, if you got bubbles coming up in your coolant, if you have cooling in your oil, or if you
2:33
got a ton of white smoke, and then another really common symptom of a blown head gasket is the
2:37
car just runs like crap. And this one's running just fine. It's not having any issues
2:43
So I'm a little bit skeptical that I have a blown head gasket, but I am losing a lot of coolant
2:49
and I have not been able to find the coolant link anywhere. So finding coolant links kind of goes hand in hand
2:56
So another thing I've done is I've got a board under here
3:01
and that's basically to catch coolant to see if I've got a coolant
3:05
to see if I can basically find exactly where my coolant link is
3:10
And actually, in fact, if you haven't seen my video on finding coolant links
3:15
then I'll leave a card in the top right of this day
3:19
video. It's a pretty good video on finding coolant links more generally. But now we are going to jump to
3:25
a coolant pressure test. Now, this is a test I like to apply before I go ahead and apply a compression
3:31
test because if I can apply the pressure or the compression test, because if I can apply this
3:37
pressure test to the coolant, I can find the coolant link, then no head gasket issue. Now, I'm
3:43
somewhat suspecting that my coolant leak is actually coming from the inside which will could be a heater core or some one of the hoses going to the heater core It quite possible But I a little bit worried about that because my dash does not my floorboards don seem very wet
4:01
And I'm losing a decent amount of coolant. So what we're going to do, I got this coolant pressure kit from Advanced Auto
4:10
Number five, if you get the same kit as me, it's got a ton of
4:15
it's got a ton of different adapters so number five is the right one for this vehicle this is a bmw
4:22
e36 of course but this is going to be the same test on any bmw really because you're not going to have
4:29
a coolant cap on the radiator you're going to have it on the reservoir so i'm going to pop it on here
4:34
so now i've got my pump attached to my adapter right here i've got it tightened up and you're going to
4:43
want to pump it to between 15 and 20 PSI somewhere around there and you're just going to let it sit
4:49
and look around. And I didn't show this, but you're going to want to have your coolant. It doesn't
4:55
need to be necessarily topped off, but it needs to be at least, you know, it needs to be at the
5:00
colt line or a little bit higher. You don't want your coolant to be low when you're doing this test
5:05
Okay, so I've got it pressurized at 18. Leak right here, and I swear I just heard a leak underneath
5:13
Let's see. So we're definitely leaking from the reservoir. Looks like it's leaking from the bleed screw and it's dripping down the side of the reservoir
5:25
Now hopefully that is my only leak As you can see the pressure is dropping Now if your pressure drops within the first two minutes you know you have a leak And as you can see here I got a leak coming from in that reservoir All right so it also looks like I got a leak coming from this hose So I can just tighten that down a bit Okay so once you have found the leak
5:57
hold this down, and that will remove the pressure, and then you're good to go. That's it. So it's looking
6:09
like this car probably does not have a head gasket leak. So I hope you all enjoyed this video
6:15
Basically, this is the route that I try and take for head gasket leaks. I will first do the
6:20
really, really basic stuff, and then I'll do a coolant pressure check because if it's not blowing
6:26
wine smoke and you're not, it's not running like crap and you don't have water in the oil
6:33
then there's a good chance that you just have a coolant leak. So to me, it's better just to pinpoint that
6:38
first and see if there is an external coolant leak before you start doing compression tests
6:43
The next step I would do if I still didn't find the leak is I would start really thinking
6:49
it was a head gasket leak, especially if my floor boards were not soaking wet
6:55
So the next step I would do is pop the valve, pop this cover off and pull out a spark plug
7:02
and see how clean it is. Now, when you have a head gasket leak, then oftentimes
7:08
The coolants will actually come in contact with the bottom of the spark plugs
7:13
When you pull them out, they'll have this white coolant film on them
7:17
or they'll be really, really clean, like they'll look brand new on the bottom side of it
7:22
And that'll tell you that you're getting coolant onto the spark plugs, and it's mixing in
7:27
And then after that, I would do a compression test. So I hope you enjoyed this video
7:32
I'm going to be making a lot more useful and helpful videos as I'm restoring this E-36 back
7:38
to its former glory. Y'all have a good one
#BMW
#Vehicle Repair & Maintenance