Ok, so I overfilled my coolant the other day and drove it for about 30 miles. When I got home and turned the car off, I could hear the coolant running out. I opened my hood and the cap was off and coolant spilled out everywhere in my driveway. I filled it to the min line and let it sit for a day. I drove it to work today and back home. There was a small leak of fluid in the driveway. I checked and it appears it's coming from under the expansion tank. I just drove it again for 20 miles and back home. Even smaller leak of fluid. thanks I was searching forums and I did a semi-bleed to push air out of the system because my heater, while it gets pretty warm, it just doesn't feel as hot as it used to when I had it all the way up. Any suggestions? Thanks in advance!!!!
Smaller leak just now:
Last edited by ryunohadouken; 02-16-2018 at 07:37 PM.
Try bleeding the car properly with the nose being jacked up 5-6"'s and then we can start having an idea. The bleeding procedure could be found at the FAQ's on the top of this forum
C217 S63 AMG S Cabriolet ( Daily )
E87 116i with mild cams, headers, cold air intake making 136 bhp Lol (My Learning Track Car)
E36 328i Sport ( Project in making and future race/track car )
Check and fill to the min. line every morning on a cold engine for 2~3 days,
that should eliminate the air in the coolant.
Oh I thought you have to open the bleed screw to bleed the car while adding coolant with the engine running until no more air bubbles come out of the bleed screw preferably with the front jacked up
C217 S63 AMG S Cabriolet ( Daily )
E87 116i with mild cams, headers, cold air intake making 136 bhp Lol (My Learning Track Car)
E36 328i Sport ( Project in making and future race/track car )
Overfilling the cooling system is verboten. What’s likely happening is coolant got everywhere and what you’re serving is the remnants dripping. BUT, definitely keep an eye on the coolant level. If the cap came off you’ll need to buy a new one.
Ooohh right! I was just wondering and thought the E38 might of had a different procedure!
C217 S63 AMG S Cabriolet ( Daily )
E87 116i with mild cams, headers, cold air intake making 136 bhp Lol (My Learning Track Car)
E36 328i Sport ( Project in making and future race/track car )
just to clarify - a 2002 745 is more likely an e65 or e66.
'95 325iS - auto to manual swap done!
If you over filled it, is it possible that you cracked the overflow bottle? Or is there a sensor on the bottom like the e36 tank that can leak on occasion?
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
You need to take the car to a BMW pro. A pressure test of the cooling system will be step 1; but you may be facing far greater issues than whether the expansion tank is leaking every now and then. You might have compression in the cooling system (in other words, blown head gasket), you might have the hugely common water pipe failure in the middle of the "V" of the engine.....or maybe you've got a bad hose at the expansion tank or elsewhere. Have you replaced the expansion tank itself? It's WAY overdue, as are all the hoses and plastic pipes in the system.
Just so you know, a BMW which cost ~$70,000 new requires about $3000 a year in maintenance and repairs. An '02 745 is probably the most troublesome and failure-prone BMW ever made. Well, at least until N63 engines came to be........
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
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