Coolant leak while changing spark plugs
 

I just hit 100k miles on my 02 4.4 and changed my spark plugs today (Bosch). I did the left side first and really had to crank on the first few plugs to get them out. I was done w/3 plugs when I noticed that a small puddle of coolant had dripped on the floor below the coolant expansion tank. Not good, I thought to myself. It looked like the leak started somewhere below the expansion tank, but I could not see exactly where the source was.

I suspect I knocked a coolant hose/fitting loose, but it only seemed to leak that one time. No leaks after so far and I have driven it several times already.

Could I have hit a fitting or seal that popped back in place? It seems odd that it doesn't leak anymore, but I'm just waiting for my temp needle to spike and find a gusher in the engine compartment. This forum has me paranoid about spontaneous leaks.

Love the X5 but extended warranty has been key to owning it - a major transmission failure last year, problems with self leveling, front suspension/steering repairs, seat heater replaced, and so on.

keep some duct tape in the car, you can temporally fix a cracked/broken hose enough to get her home/to a shop. if you lose enough you need to get some water in the mean time.

remember, dont top it off with regular tap water. (use Distilled Water and bleed the system if necessary.)

oh yea, go to realoem.com and find your model X and you can get detailed information on all the parts making up the coolant system. also, check the coolant tank where the sensor plugs in to see if its leaking. may just need some cleaning.

You're supposed to use NGK Iridiums BKR6EQUP on the 4.4 V8, not Bosch's. I think if you can get away w/ it, you should exchange them for the correct plugs. At 100k, you're better of doing a complete cooling system change also.

http://www.xoutpost.com/bmw-sav-foru...?highlight=ngk
http://www.xoutpost.com/bmw-sav-foru...?highlight=ngk

Letting a BMW slide on it's maintenance will snowball into many worse things, and at 100k, you're due for many more things that just spark plugs.

This X5 V8 has rather elaborate coolant systems, it can leak in so many places. I just discover I have leak in oil heat exchanger that was not noticed (either the small crack got filled up by dried up coolant crystal or when hot it seals it self up).
For a moment I thought I owned an R71 blackbird that leaks on the ground but not in the air :-)

Duck tape in the trunk may not be a bad idea.

FYI, @58K miles, my WP looks great, thermostat looks new as well. but the upper radiator hose leaks so I decided to overhaul all for preventive maintenance.

I've read several of your postings on the subject, but why do you keep referring to these NGK BKR6EQUP as "Iridium" as they are clearly not? BKR6EQUP are the OEM equivalent of the "Laser Platinum+4", NOT "Iridium" as you have mentioned on multiple posts. If you want to vear away from the OEM Platinums and want to experiment with the single electrode Iridium, then the proper part number for that Iridium plug should be BKR6EIX.

BTW...the Bosch is an acceptable replacement plug as both Bosch and NGK are OEM suppliers to BMW. Just because a few on certain message forums had bad experience with Bosch for one reason or another doesn't make them bad plugs.

I probably pushed against a hose when I was yanking on the spark plug wrench and caused the leak. I just wonder if there is a release valve or some part of a hose fitting in that area that could leaked when pushed.

I don't remember the part number and I'm pretty sure this thread was the first time I gave an actual NGK part number. I posted two links two other threads just for that reason, so just my opinion isn't used. My previous posts were in regards to getting them at Autozone or somewhere cheaper than the dealership, so I believe you're misquoting me. That part number I posted was just a copy and paste from ECS tunings (overpriced) sale of NGK spark plugs. :: ECS Tuning :: NGK Spark Plugs BKR6EQUP ~ Set Of 8 - Now Available !!! - Bimmerforums - The Ultimate BMW Forum Thanks for your correction on the NGK part number. I agree the Bosch's can be used, so it maybe it was a little abrupt to say that he got the wrong ones. All these threads end up coming around full circle, and coming from the 7 boards, dealerships techs on these and other forums, etc. the NGK's are just the more popular ones since we share the same motor...