Oil mixing with coolant in 1998 528i M52 BMW

[Young 23]

I've posted recently about fixing my 1998 528i m52 BMW's head gasket problem which resulted from a crack on the cylinder head in piston area four. Now, this is my very first car and it happens to be a BMW because I liked it very much so I'm asking all you veterans if you could help me out with a few questions. I depend on my car to go to school and its almost about to start again! Anyways, does anyone know how the coolant mixes with the oil due to the crack in the cylinder head? I understand that people say it happens when a crack occurs, but I'm asking how does the coolant physically get into the oil. Where does it travel through in order to do so? Sory for all the questions I'm going to be writing but I do need help. If the car is driven containing a significant amount of coolant in the oil, resulting in the caramel/milky color, is it bad for the engine (I heard it was corrosive and eliminates the oil's lubricating effect)? The car overheated but it never seized on me and drove great as always except for the fact that it was overheating (of course I quickly pulled over to stop driving but there were no physical symptoms indicating failure other than seeing the gauge go up). I also need to know if anyone knows a proper procedure to clean it out using diesel or anything alike. If anyone could answer these questions I would greatly appreciate it. I am also posting two other separate threads so if anyone could check those out as well to help a novice like me I would greatly appreciate it. Thanks.

[jclausen]

it comes thru the headgasket, if it overheated enough to crack the head, the head also warped. Since coolant and oil go thru the head gasket, the head warps, those holes in the head gasket that are normally are sealed no longer are and the mixing happens. Only time will tell if the milk shake will affect the other parts of the engine. Normally you might just swap out the engine then replacing the head. Also on over heats the bore can be come misshapen so now after the repair the engine could use oil. There is probably some product to clean out the engine. Multiple oil changes would help.

[Young 23]

By the bore being misshapen what exactly are you referring to? What is it? And well hopefully it didn't, as I do not have the money or the equipment to change an entire engine. However, I really appreciate your explanation of how the oil/coolant mixing occurs. It makes a lot more sense because I just didn't understand how there was clean coolant accumulated in the piston and the engine cooling passages but only the oil was mixed. Made me wonder why there wasn't any oil in the coolant system itself. But thank you I really appreciate your description and your help. Thanks! I'll try to post about my car once I fix it to let you know how it turned out. Take care brother

[geargrinder]

As Jclaus said, its not often a true 'crack' although it can be in extreme cases. Mostly its just this big flat gasket that has holes through it for oil passages and holes through it for coolant passages. The coolant is under pressure so if that head seal starts to go its easier for coolant to blast into oil-places than it is for the oil to get into coolant-places, unless the damage is really disastrous.

I'm gonna guess decent chance your engine is probably junk. Probably have to face the music there my friend. Sorry.

I mean sure yes it might be certainly fixable but what jclaus is saying is that quite often its far more costly at this point to pull the motor and clean it up and perhaps 'deck' the head and block (i.e. machine them to clean up and flatten the surfaces) etc. etc. etc. than it is to buy a used junkyard motor and just toss it in there instead. So economically​ its junk even if it would / could be repairable.

[Young 23]

Well actually that may be exactly what I’ll do because I have no equipment to be able to change an engine. However, I’ve heard of people having their cars mix oil and coolant, overheat, and seize up and still manage to get them up and running. But who knows you might be right and honestly Ik it’s a bargain but I’m going to take the shot anyway. Do you know if the coolant and oil just siting in the engine can cause damage by just being there? Like what are the effects it has without the engine actually being in motion? Btw I’m not machining the block, just cleaning it really good. I’m kinda placing my bets on it bc it’s cast iron but I should check it with a straight edge to be safe. Thanks for help btw I appreciate that 😌

[geargrinder]

Now much of that was hard to decipher but I think I understand the gist.

Hey who knows. Maybe you can just change your head gasket and it’ll all seal up fine. Or maybe you’ll waste all that time and money and end up w a junk motor anyway.

Pull the the head and see.

By the way way if you’re asking all these questions you’re almost certainly not equipped to solo a head gasket job, (do you own tools? Torque wrench? Any mechanical experience at all?) but, good luck anyway. My money says this turns into a disaster as these “I am broke so I can’t listen to any good advice” situations always do....

[effduration]

you haven't brought it up, but I would NOT try any of that "stop leak" stuff that supposedly seals coolant system leaks. It may provide a temporary fix, but will wreak havoc on your cooling and heating system, particularly your heater core.

As has been documented here many times, a used, running, compression-tested replacement engine is a cheaper, quicker, and easier fix than doing a head gasket. Further, M52 engines (not M52TU or M54), like your's, are pretty damn cheap, particularly from parts cars. I have done both an engine swap and a HG, and you end up needing fewer tools with an engine replacement than a head gasket.

[geargrinder]

^^^^^ zact .

[Young 23]

Just to quote all of you, I ended up going for the cylinder head replacement, as it did indeed have a crack. Got a remanufactured one with warranty, swapped the cams, got the engine surface nice and clean, and I did indeed end up soloing the entire job. I only asked one mechanic for advice on what to do when I dropped the head, and that was about it. The entire job I did myself and fortunately I sealed her up in early September and I’ve been driving my car ever since. Around 2.5k miles since it last drove with around 3 oil changes in between.I even drove upwards to 110 mph when going to Champaign in Illinois. I’ve done more work to it since, and I had one check engine light pop up for an o2 sensor about 5 months back, and after replacing it it never came back on. I passed emissions testing, the car burns no oil nor loses coolant, and no leaks are seen anywhere other than a slight one at the oil pan gasket ( which I have not yet replaced). I had limited mechanical knowledge, nothing compared to this really. I did acquire torque wrenches and timing tools for the fine details in putting the head back on, and I used genuine parts where I felt it mattered, such as the HG, head bolts, washers, etc. I DID NOT use stop leak or anything similar as I’ve never really believed in those products and doubted their effectiveness and their contribution to the well being if the engine. Needless to say, I’m happy I took the risk because now I’m finally enjoying driving my car without losing the money I had already invested into it. I just love the car overall, and being my first car I didn’t want to give up on it. And it worked out great in the end! Thanks for all the helpful advice from everyone! Only downside was the time it took to get it done since I don’t have a garage and the weather outside doesn’t always cooperate. I also lost my master key 😅, but apart from that, seems like I have a car to last me a few more years hopefully.

[Santaclaus4]

Good job and congratulations for getting it sorted out. Many aren't so lucky.

[Young 23]

Good job and congratulations for getting it sorted out. Many aren't so lucky.

Thanks brother. I appreciate that, and when I meant soloing the job obviously I researched and found info on the subject, but the hands on part was me entirely. But thanks again and you’re right unfortunately not everyone has the same luck. Btw I saw your car, pretty badass. Hope you keep caring for it. Stay safe out there.

[philly98540]

Nice work! The fear and confusion of what it takes to do a serious job is behind you. Understanding the value in doing it yourself will last a lifetime.

[Aubergine]

Just to quote all of you, I ended up going for the cylinder head replacement, as it did indeed have a crack. Got a remanufactured one with warranty, swapped the cams, got the engine surface nice and clean, and I did indeed end up soloing the entire job. I only asked one mechanic for advice on what to do when I dropped the head, and that was about it. The entire job I did myself and fortunately I sealed her up in early September and I’ve been driving my car ever since. Around 2.5k miles since it last drove with around 3 oil changes in between.I even drove upwards to 110 mph when going to Champaign in Illinois. I’ve done more work to it since, and I had one check engine light pop up for an o2 sensor about 5 months back, and after replacing it it never came back on. I passed emissions testing, the car burns no oil nor loses coolant, and no leaks are seen anywhere other than a slight one at the oil pan gasket ( which I have not yet replaced). I had limited mechanical knowledge, nothing compared to this really. I did acquire torque wrenches and timing tools for the fine details in putting the head back on, and I used genuine parts where I felt it mattered, such as the HG, head bolts, washers, etc. I DID NOT use stop leak or anything similar as I’ve never really believed in those products and doubted their effectiveness and their contribution to the well being if the engine. Needless to say, I’m happy I took the risk because now I’m finally enjoying driving my car without losing the money I had already invested into it. I just love the car overall, and being my first car I didn’t want to give up on it. And it worked out great in the end! Thanks for all the helpful advice from everyone! Only downside was the time it took to get it done since I don’t have a garage and the weather outside doesn’t always cooperate. I also lost my master key , but apart from that, seems like I have a car to last me a few more years hopefully.

That is really awesome! Ironically I was doing the job at almost the same time but working full time and with life happening, it carried on almost 5 months. When someone searches this in years to come (because I have been that guy), I also used OEM BMW HG in the +.3MM size, along with OEM BMW head bolts, and a cylinder head that I pulled ($60!) and had a good machine shop check and clean up. Working on the iron block has made the learning pretty safe as I knew that my block would not be warped or need time serts for the head bolts. At least here in the northeastern US, the M52 cylinder heads are still fairly easy to find at junk yards.

Good job and congratulations for getting it sorted out. Many aren't so lucky.

So many of these cars have died due to this issue....

Nice work! The fear and confusion of what it takes to do a serious job is behind you. Understanding the value in doing it yourself will last a lifetime.

Same here! There is no better feeling than getting it back together and running well.

[ross1]

That is a very big job for a first timer, especially replacing and timing the cams.
Good work!

[Ed CT]

This is a great success story for a few reasons: Young23 got the complex and technical work all done basically solo (on the physical side), This forum earned it raison d'etre by helping him out on the work (on the virtual side), and, Another E39 was saved from an early grave in the boneyard (on the spiritual side).

And to top it all off, Young23, after completing all this work, posted follow-ups to all his threads!

(Sorry for the post - just spacing out & weirding-off during lunch)

[Young 23]

Nice work! The fear and confusion of what it takes to do a serious job is behind you. Understanding the value in doing it yourself will last a lifetime.

I was told similar things after I fixed it but no one worded it as well as you just did. You’re absolutely right! I was definitely scared of the job itself and finding out whether or not I succeeded in the end. But now that it worked out I definitely feel a great sense of triumph for taking the risk and doing it myself, as I had 2 friends from an automotive program offer to help me but left me in the lurch when it came down to it. I don’t blame them. It was a big job, but still I think it was better this way so that I could be held accountable for everything that happened. Nevertheless, thank you!

[Young 23]

That is really awesome! Ironically I was doing the job at almost the same time but working full time and with life happening, it carried on almost 5 months. When someone searches this in years to come (because I have been that guy), I also used OEM BMW HG in the +.3MM size, along with OEM BMW head bolts, and a cylinder head that I pulled ($60!) and had a good machine shop check and clean up. Working on the iron block has made the learning pretty safe as I knew that my block would not be warped or need time serts for the head bolts. At least here in the northeastern US, the M52 cylinder heads are still fairly easy to find at junk yards.


So many of these cars have died due to this issue....



Same here! There is no better feeling than getting it back together and running well.

Thanks! It really is and damn I feel you and I have to say that I was lucky in that regard. I had just graduated from community college and was going to take a few more classes in the summer to complete another degree, but I was not working at the moment and I had a fairly good amount of savings to carry me through the year as well as to aid me in the repair of my car. Hope that whatever life threw at you wasn’t anything that you couldn’t handle. Best wishes. But 5 months is about the time that it took me also. I started taking out simple things from the car such as the air box and things like that around May. Then I started diving into it head on in June and finished around early to mid September, so around 5 months. What slowed me down was the weather mostly, as I had to work outside and rain, wind, the heat, and the sun itself at times proved unbearable, but I had to finish before summer turned to fall and fall turned to winter. And nice! I did the same but used a remanufactured head because I couldn’t find m52’s in my neighboring junk yards. The labor to pull it might have also been pointless if it ended up being cracked. Glad you got one in good shape. Regardless I fully agree with you and that is one of the only reasons that I agreed to proceed with the job since the block was cast iron. I saw all the videos and stories of the headbolts pulling the threads due to the overheating of the aluminum blocks. Didn’t hear anything like that in regards to the iron blocks so that was a huge relief for me. But glad everything worked out for you! It did right? And thanks again 👌

- - - Updated - - -

That is a very big job for a first timer, especially replacing and timing the cams.
Good work!

Thanks! It means a lot for me to hear that. Just made sure to find a procedure that proved successful and then took my sweet time to do it right. Hopefully this will help me improve my ability to fix my car in the future. Thanks again!

[Young 23]

This is a great success story for a few reasons: Young23 got the complex and technical work all done basically solo (on the physical side), This forum earned it raison d'etre by helping him out on the work (on the virtual side), and, Another E39 was saved from an early grave in the boneyard (on the spiritual side).

And to top it all off, Young23, after completing all this work, posted follow-ups to all his threads!


(Sorry for the post - just spacing out & weirding-off during lunch)

Thanks for the comment! I liked the way you described it ha. And with my French knowledge I can say that by this forum helping me it earned its “reason to be” since it helped which is what you said right? But yea I’m really glad I saved the car from an early death. I would have been devastated to see it go so soon. And yea I should have done the follow-ups on my threads a long time ago but I figured I should do them now since I posted another thread a few days back. I figured it should be like a thanks to everyone who took their time to comment on here to help someone who they didn’t know nor had any reason to help. Given everything came out successful it was therefore necessary to inform those on the good results. But hey thanks for commenting despite being on your lunch! Merci beaucoup et enchanté! Bonne journeé!

[Santaclaus4]

Now take all those new skills and help me replace the heater core in my daughters car. Lol
I'd much rather tackle a head gasket than remove the interior of a car.
All those plastic trim pieces are a frustrating puzzle and difficult to remove without breaking them. Grrr…
Good weekend project with my daughter though.

[Young 23]

Now take all those new skills and help me replace the heater core in my daughters car. Lol
I'd much rather tackle a head gasket than remove the interior of a car.
All those plastic trim pieces are a frustrating puzzle and difficult to remove without breaking them. Grrr…
Good weekend project with my daughter though.

Lmao I’d help you if I could tbh. I’ve done one before with my cousin and yea it’s not too fun but what can you do. Although between the two I’d rather not do any of them lmao. But definitely sounds fun to do with your daughter! Maybe one day I’ll do work on my car with my own ha. Best of luck!