BMW Battery Question 2001 E38

Tony Owner/Technician Missouri Posted   Latest   Edited  
Resolved
Electrical
2001 BMW 740i 4.4L (M62) 5-spd (5HP-24) — WBAGG83411DN88473
Weak Battery

Hi, I'm not too familiar with BMW and since I won't see the car until tomorrow I'd like some correction or assurance. The main reason I will be looking at this 2001 740i is for a comprehensive check out to let the owner know of any "hidden" issues. He just called (too late for me to call around town tonight) and said his battery is very weak, so I may need to replace it as well. This is a E38 - so it doesn't have IBS, therefore no need to register the battery replacement, correct?

RealOEM parts list for the battery is fairly useless to me:

… EP Battery 50AH, … EP Battery 61AH, … EP Battery 70AH, … EP Battery 90AH, … EP Battery 92AH AGM, … EP Battery 110AH

Some OEM sites list a single part# … at $138.44 list. I'm skeptical. Is this legit?

Aftermarket sources call out a H9 / group 95 conventional lead-acid battery. Is that the correct or best option?

0
Jose Technician
California
Jose
 

Put the biggest battery you can fit in there. H7, H8, H9 I’m sure they all fit in there. Lead acid.

+3
Ð Awarded
Agree
Thanks
Tony Owner/Technician
Missouri
Tony
 

Cool, thanks Jose.

0
Ð Awarded
Manuel Diagnostician
New Jersey
Manuel
 

Bmw used different sized batteries depending if vehicle had cellular phone etc

+1
Ð Awarded
Thanks
Tony Owner/Technician
Missouri
Tony
   

Good to know, thanks Manuel. {Edit} This damned thing still has the original cell phone in the center console cradle. It looks like what E.T. used to phone home.

0
Ð Awarded
Bill Owner/Technician
Michigan
Bill
 

i would use a Interstate MTP95R/H9 it will be your best choice for the vehicle.

+2
Ð Awarded
Agree
Tony Owner/Technician
Missouri
Tony
 

Thanks, I am suggesting an H9 but I don't deal with an Interstate distributor.

0
Ð Awarded
Dan Owner
Ohio
Dan
 

Tony. Thank God I haven't seen any of these fine machines in a long time! Most of the ones I get calls on or get towed in get removed the same way and end up in the dump. Honestly that's where they belong, IMHO. On your comprehensive eval. pay attention to oil leaks, crankcase pressure (16.0 mBar) Timing chain issues…if it's got over 100K tell em to dump it. I believe your Battery question…

0
Ð Awarded
Tony Owner/Technician
Missouri
Tony
 

Luckily he knows already it's an oil leaking time bomb, but he'll probably ride it to the junkyard that way. As far as the crankcase test, this is a spec at hot idle? Do you just attach gauge to dipstick tube or should something else be done as well for this spec to be valuable? Thanks for the advise.

0
Ð Awarded
Dan Owner
Ohio
Dan
 

Tony. Glad he knows it's a black hole on wheels! :-) I use a magnehelic gauge, dipstick is a great point of entry if you don't have a dedicated fill adapter, regular vac. gauge won't show anything! I don't know if any of the common pressure adapters will go this low, are that sensitive?? Someone will know! Of course lets mot forget about the oil burning issues at prolonged idle….. Best, Dan…

0
Ð Awarded
Tony Owner/Technician
Missouri
Tony
 

I have a digital manometer, it will read in this range.

+1
Ð Awarded
Thanks
Tony Owner/Technician
Missouri
Tony
 

Dan, I got a fairly steady -12.5 mBar (tool zeroed and referenced to atmoshphere). Attached is a shaky cam video of me trying to hold the phone+meter and keep the hose out of the cooling fan. Does this indicate too much PCV volume or is this normal?

0
Ð Awarded
Dan Owner
Ohio
Dan
 

Morning Tony. I assume it was idling @ 675-800. Take a look at the Vent diaphragms for rupture, holes. F/T should be elevated or perhaps engine is just weak? Best, Dan @ G.E.A.R.

0
Ð Awarded
Tony Owner/Technician
Missouri
Tony
 

Originally you had stated 16mBar as a spec, and since I don't know squat about BMWs nor how their PCV systems perform at idle I took that to mean 16 mBar “pressure” as was the crux of the discussion, not 16 mBar “vacuum”. So these engines and their fairly complicated PVC systems still act fairly similarly to what I'm used to. I don't think that 3.5 mBar above spec is a nail in the coffin for…

0
Ð Awarded
George Diagnostician
British Columbia
George
 

Hi Tony depending on your coustermer driving habits it might be a good idea to use AGM battery which can handle key off draw better alot of them came originally with a valve regulated battery which is what a AGM battery is

-1
Ð Awarded
Disagree
Tony Owner/Technician
Missouri
Tony
 

Thank you, that might be a good idea; I think this does sit for extended periods ever since Covid.

0
Ð Awarded
Paul Technical Support Specialist
Colorado
Paul
 

No battery registration if no IBS, for sure. We have found BMW battery prices to be pretty reasonable.

0
Ð Awarded
Tony Owner/Technician
Missouri
Tony
   

Thanks, Paul. Local dealer is one week out on the battery and states 278 clams list. Doesn't know if it's AGM or conventional.

0
Ð Awarded
Tony Owner/Technician
Missouri
Tony Resolution
 

I did install a 950 CCA group 95 battery and all is well with the electrical system. It was just a case of a 5 year old battery with an intermittent failure that caused the occasional starter relay clicking / weak crank symptoms. I caught it in action right after charging the battery so I chalked it up to an internal plate failure when hot.

0
Resolution Ð Awarded