Up next in 10
How to Tell if Your BMW Head Gasket is Blown (and Find Coolant Leaks!)
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