Issues after cooling and electrical overhaul

My 02' 325CI (I'm the original owner, bought new in November of 01') has been having some issues lately.

The first was a dead thermostat, as evidenced by the car refusing to warm up at high speeds in cold weather (stuck open). I lived with that for a few weeks, while planning to change it.

The second, however, was what I thought was a battery that had died (7 years old). I replaced it with a new one, and that worked fine for 5 weeks, until the car died, and wouldn't charge the battery. The battery charged fine with a machine, so I figured either it was the alternator or voltage regulator.

I wasn't thrilled with the conditions of the bearings, so I opted to swap the whole unit. While I was in there, I did a cooling overhaul consisting of radiator hoses, themostat, and water pump. I know about the expansion tank, but the local stealer wanted $130 for it, so I'm going to order it and do it later.

I also noticed worn belts and pulleys, so I replaced the entire mechanical tensioner assembly for the AC, plus the idler pulley and serpentine tensioner pulley (the pulley only, not the whole hydraulic tensioner) for the alt/PS/WP, as well as new belts.

Lastly, I noticed a couple of chips in the water pump pulley, so I replaced it with the URO aluminum one (same size).

Before I put everything back together, I noticed three things, but didn't have time to fix them:

1. Small crack in the power steering pulley (also composite). Plan to replace that with the URO aluminum one later this week.

2. The hydraulic tensioner for the serpentine belt was incredibly hard to detension(to get the belt on), to the point that I needed a breaker bar... That really worried me, but I had no time to fix it.

3. Midway through the overhaul (I did it a few hours a day over a few days), I realized that the newly installed alternator was warm (almost hot to the touch). This was with the car having not been driven in several days, and the rest of the engine compartment was cool... Shortly after, the battery died (it was fully charged). Not good. Bad alt? It's a refurb from NAPA (best I could do on short notice). I mainly chose it for the lifetime warranty.

Anyway, put everything back together, but had to rush, as I needed to drive to Union station to catch a train to NYC for a business trip.

Coolant refresh seemed to work fine. Temp needle was dead center, I properly bled it, etc.

Electrical and the rest was not so good. I felt like I was driving an electric car. I was getting belt squeal, a whine, and the lights on the dash were doing interesting things... Further, while the idle was fine, I was getting some weird surging in throttle response (belts slipping???).

I made it into the station ok to catch my train, and disconnected the battery before I left the car in the lot (to keep the alt from draining the battery). I'm gone for three days, but want to get parts ordered.

I'm thinking:

- New hydraulic tensioner? Would a failing hydraulic tensioner put way too much pressure on the belt / be hard to detension? Compared with the new mechanical tensioner on the AC belt, it's night and day.

- New power steering pulley. It looks like I might need a puller to get the old one off? Has anyone done this?

- New alternator. Go back to NAPA and ask them to replace, or try to get my money back and try my luck with either a refurb bosch from alternator pros or autohaus AZ, or even try just a voltage regulator?

- Anything else I'm missing? Short in the system somewhere? Would this cause the alternator to heat up? Would it cause the old alternator to stop charging the battery? The new battery is definitely getting charged when the engine is running, it's just when it's off.

- Do my symptoms match my observed issues?

Hydraulic is tighter than mechanical, it seemed to me, so probably not an issue. I use a 14" breaker bar all the time to detension my tensioners...and the hydraulic still takes some push.

The Alt issue...first I've heard of that here...and usually, stores don't like taking back used electrical parts, so don't be surprised if they give you the option of giving you another remanned alt, or "sorry, can't give you money back."

So, I've been thinking about this alt issue some more, and it seems to me that the only ways it would feel hot when the rest of engine is cool...

1. You could be deceiving yourself...feeling the engine cover and not the engine itself--alt is a pretty solid hunk of metal with lots of heat capacity--so make sure you're comparing it to the block. And I wonder if you might have been noticing it absorbing ambient temps from maybe the hot driveway the car was sitting on? Still, the way you describe it, it sure does seem like an issue.

2. Some 'feedback' from the battery which I can't understand. The single cable and the connector only go one way...so I'm not sure how that could be.

A new battery could be dead, not from the alt not charging, but from connections being bad...loose or corroded...so check grounds...make sure cables are clean and tight...lift up on cables...sometimes they don't fit tightly on the terminals.

Still, what you describe is odd. Use cluster test to measure voltage off and on.

BTW, I'm going to be in Union later today, I'll PM you my number...if you're around I'd be happy to look at things with you. Not sure what I'll see, but I can always look!

Doug

Thanks for the reply, Dmax. Unfortunately, it looks like we crossed paths. I'm almost to Penn Station, and will be in the city for a couple of days. The car is locked and in Union Station's garage, with the battery disconnected.

Just to give you an idea, when I did some brief reading about this, I saw something about this being a symptom of a bad diode. Something about the diodes being the devices that allow electrcity to throw through one way, but not the other (kind of like a valve).

Also, there was something about the fact that when I connect the black terminal to the battery (I do red first), I've been getting a bit of sparking. I think it mentioned that was a symptom.

I'm going to do some more googling in a bit.

The one thing I know is that when I felt the alt being warm (almost hot), the engine had not been run in days, and never with the alt in it. Certainly possible this is a perception issue, but combined with the fact that something killed a fully charged battery without the car being switched on, that would be a big coincidence.

Got the alternator replaced under warranty, and swapped out the PS Steering pulley (the cracked one), and the hydraulic tensioner (the tensioner itself, I had already switched out the pulley).

Silky smooth now, no lights on at all, and no problems with the battery draining when the car's not running. I'm very happy.

Awesome

Thanks for posting your fix!

Craaaaaap. Just got my coolant flushed at the dealer ($150), and they let me know my oil filter housing gasket is leaking, and my fuel pump needs replacing.

I came across the OFHG DIY's when figuring out how to do the alternator. That would have been a great time to do the OFHG... Guess I'll be getting oily this weekend or next.

The good news is I'm very comfortable with all the steps leading up to the alternator removal, and can probably get that out in 20 minutes now.

Well, did fuel pump last night, and wasn't too bad. The key is to get the car up on jack stands nice and high to give yourself plenty of room to work. Also, I wore a full face shield to keep from getting sprayed with gas, although that didn't wind up being a problem (not much came out).

I never pulled the fuse or opened the gas cap, but did buy fuel line clamps from Harbor freight. Golf tees weren't necessary. One thing I think may have helped quite a bit was jacking the front of the car significantly higher than the rear, which might have kept gravity from pushing fuel through the lines...

Those that bend the shield out of the way are smoking dope, just remove the final two nuts that are kind of a pain to get to, but not too bad.

I also went ahead and redid everything, including all six clamps, all three fuel injection lines, and the vacuum hose. The fuel injection lines cost a total of $10 for 18 inches of prepackaged, 5/16ths hose at Advanced Auto Parts. A foot of the vacuum hose was like a few bucks. The clamps were the most expensive, like $3 each at the stealer.

While the fuel injection hoses were in fine shape, the vacuum hose was not. Still, being able to just cut all the hoses and pull the filter, then remove the rest of the hoses from the lines, made the job way easier. For fun, I tried to pull it off, including using a trim tool, and a dedicated fuel hose removal tool, and it was a PITA.

So, I say spend the extra $10 and do your hoses while you're at it, if only for the sake of convenience.

Lastly, be careful when tightening the nut onto the post that holds the fuel filter clamp. I snapped off the stud with just a socket and a stubby 3/8 rachet (and very little torque). I wound up just JB welding the nut back on... We'lll see if it holds.