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Coolant leak

4K views 42 replies 11 participants last post by  Dionte 
#1 ·
Since my grandmother and her boyfriend have been in town from Germany these past few weeks, my mother has been using my car to drive to work and she lets them use hers. She came home yesterday and said that the coolant level light came on. I checked it out while they went out to eat. There was literally no antifreeze! I poured more in and saw that it was leaking . It was getting dark so I couldn't see exactly where it was coming from. All I saw what looked like the coolant splattered all over the engine. I'm assuming there may be a crack in one of the hoses. But while I'm in school right now, my grandmother's boyfriend will be checking it out. I'll update you guys when I get home.
 
#3 ·
This could be a cracked hose or a fitting let go. It would have to be some sort of main vein for it to splatter over the motor.

I agree with Steve, DO NOT let it over heat. Especially those M30s (big dino motors) need to keep their cool.

I dont know about the M30s, but M50s were fitted with plastic tstat housings that would age and crack after a time (i replaced mine with aluminum premptively) which could be your issue, if it is indeed plastic. My M20, which i've found is more similar to the M30, did not have a plastic housing, so i would wager you dont, worth a check though.

Check all lines, theres way more coolant lines that just radiator to pump keep in mind. 203k mi. will take their toll on 20+ year old rubbers
 
#9 · (Edited)
i dont know about the m30s, but m50s were fitted with plastic tstat housings that would age and crack after a time (i replaced mine with aluminum premptively) which could be your issue, if it is indeed plastic. My m20, which i've found is more similar to the m30, did not have a plastic housing, so i would wager you dont, worth a check though.
+1000. Plastic housing came apart in my hands last week when I replaced the tsat. Had a deep crack that would have snapped through at some point. Had been losing coolant for months slowly without knowing why. Rad pressure test was good. That's totally stopped now.
 
#5 ·
It's raining but my grandma's boyfriend checked it out and told me that the water pump needs to be replaced. Good thing they're not that expensive. Still a little skeptical about the hoses though, still going to get those checked out.
 
#10 ·
Replace the pump, the belts and hoses, maybe the t-stat. Flush the cooling system, clean the radiator and condersor while you have the fan shroud out. This is a good opportunity to establish a baseline on your cooling system. Do as much of this as you can afford now, it will save on labor later. Cooling systems and suspension systems are the two maintenance intensive areas on these cars. A thorough service while you are in there will give you peace of mind through the summer months. As mentioned, you do NOT want to overheat it.
 
#14 ·
What do you guys feel is the difficulty of installing a new water pump? I cant imagine it being that difficult with the right tools & i also have the Bentley repair manual. My mother doesn't want me to mess around with it. I just wanted you guys' opinion because i feel that I'm capable of changing the water pump.
 
#18 · (Edited)
Febi Bilstein i have used in the past, always been happy with them.

If the M30 waterpump is the same setup as M10/M20/M40/M50 then its a piece of cake, only tricky bit is removing the fan clutch from the hub, and of course do that before doing anything else. you shouldnt need to remove the radiator, but seeing as you will be replacing coolant, you might as well, makes access a bit easier. rememeber to drain the block of coolant too. not sure where the plug is on an M30, I'm not overly familiar with it, but i think its under the exhaust manifold towards the firewall end
 
#21 ·
Go OEM or Febi. My Febi had Alpina on it.
Made me feel all warm and fuzzy to actually have a Alpina engine part.
Then I came back to earth and realized they are for all M30s. Fun while it lasted.
 
#22 ·
I went on febi's website but I can't buy anything. They just give me item numbers, do you know where to buy the febi water pump?

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#25 ·
Few pics of the engine, not sure if you can see where some of the anti-freeze splashed over but here you go

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#26 ·
Update-
Well I got the new water pump from autozone, don't bash on me please lol. My mother insisted on buying a water pump although I offered to buy the oem water pump, she didn't want to spend the money on the oem so she got the duralast one. My grandpa and I installed it today and it seemed to be running fine until later this evening. I went to the store and on the way back it began to run hot (good thing I live right by the store). So I came home quickly and shut her off immediately. I'm thinking that she may not have been filled up all the way with coolant, considering the fact that we drained it and filled it back up without cranking up the engine. I hope its just that there's not enough coolant in there and nothing else. I'll update you guys tomorrow when my grandpa comes and checks it out.

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#27 ·
I hope you don't have a blown head gasket or cracked head. Make sure to follow the Bentley manual for bleeding air from the system. Make sure to have your heat set all the way to hot and the blower motor on high.

Once you know it is bleed properly, and if it still overheats, then you need to start looking at a head gasket problem. Does your oil look like a milkshake on either the cap or dipstick? You can do a compression test or buy a kit to check for combustion gasses in the coolant.

Good luck my friend. These in-line 6 cylinder BMW engines don't take too kindly to overheats :bawling:
 
#29 ·
Agreed that the M30 is a stout engine. Good used M30s may be hard to come by as well. If the head is not cracked, then a head gasket can be replaced. I have never tackled a head gasket job, but others here have.
 
#30 ·
Well I just filled it back up with coolant because there was barely any in there, took her for a spin around the neighborhood a few times, got the revs up a bit and she began to run hot again so I had to pull back into the driveway and shut her off. I hope its not the head, could it be the thermostat?

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#33 ·
I don't think the OP knows how to bleed the system. He is just adding coolant.

There is a sure way to bleed the cooling system on 'big' six engines.
1. After repair is made (before adding coolant) remove bleeder screw and run
a small piece of wire down the hole to dislodge any mineral deposits..
2. Replace the screw, but leave valve 'open'.
3. Open heater control valve(heater controls to MAX) and add coolant until it begins to escape from
the bleeder hole.
4. Now close bleeder screw and replace the expansion tank cap and tighten.
5. Remove the small coolant line that runs from the radiator to the
expansion tank AT THE EXPANSION tank and hold it as high as you can.
6. Now attach another hose the expansion tank in place of the one you've
just removed. BLOW (gently!!) through this hose until coolant emerges from
the small elevated radiator hose.
7. Now remove the 'blow' hose and reconnect the small radiator hose to the
expansion tank..
8. Now top off the expansion tank to the full mark.
9. Start and warm up engine and check for leaks!!
That's it. Good luck.

http://www.mye28.com/viewtopic.php?p=908817

bleed screw on thermostat housing:


Definitely look here for bleeding instructions:
http://www.nmia.com/~dgnrg/page_19.htm
 
#38 ·
I have to say that those at the most complicated set of bleeding instructions I've read. I don't think it was designed that way. That said, its clearly a bulletproof method. I've read about other methods involving vacuum pumps as well.

The bentley manual asks one to check coolant levels some time after the first bleed, and after a drive, to compensate for air not being fully purged during normal bleeding using normal methods, the first time round.
 
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