Accessory belts shredded and collateral damage
 

My daughter was driving her 2001 X5 4.4i home this weekend. Her college is about 35 miles away but she only made it about half way before she could pull over. We had her towed home and I am assessing the damage.

• both accessory belts are shredded to pieces
• The upper bolt that holds the AC accessory belt tensioner to the block sheared off leaving all of the threaded portion of that bolt (about 1") in the block. The belt tensioner and accessory belts were replaced in October 2020.
• The broken bolt rattled around and put some dents in the radiator (3 month old radiator)
• The cooling hose that goes from the bottom port on the ATF thermostat to the block adjacent to the alternator (11537500752) broke the nipple off the ATF thermostat and was severed near the other end. Consequently much of the coolant drained out of the system. And with the accessory belts shredded, the water pump wasn't being turned.
• several blades on the fan attached to the viscous coupling have been severed

I would be interested in suggestions what might have happened (what broke first).

When my daughter first noticed something was wrong she was on the freeway approaching a bridge (SF Bay Bridge). She wasn't able to pull over to a safe location until she got to the other side so she drove at least 5 miles with probably no cooling water. I have started the engine twice since and it seems to run OK. Of course there are warning lights/messages for alternator and coolant level but there is no Service Engine Soon light.

I removed the radiator for inspection and what coolant that was left in the radiator was clear and looked new. I did find a couple of dents in the radiator core, but I pressurized the radiator with air submerged in a tub of water and didn't see any bubbles from these areas. So I'm assuming the radiator while damaged is still integral.

I drained the oil and I didn't see any evidence of water in the oil.

I do see some creamy substance that looks like water and oil mixture at the outlet from the block right above the water cooled alternator. I don't really know what this fitting is connecting too? is it a cooling jacket for the alternator or what? This engine has an upper radiator hose that has a couple of branch hoses. This is one of the smaller diameter branch tubes.

At this point I am concerned that I may have a breach between the lubrication side and the cooling side because of the creamy substance found. Any thoughts about this?

My next steps are going to be to replace the AC belt tensioner and coolant hose and install the old accessory belts I saved and reinstall this radiator. At that point I can do a pressure test of the cooling system.

I am also wondering if there is a way to flush the cooling system? I remember the days when prestone sold a kit where you installed a tee fitting to your heater hose and could connect a garden hose flush out your cooling jackets into the gutter and down the storm drain. Of course this is frowned upon these days here in the SF Bay area. But is there a way to flush this cooling system?

Sorry for the long post. some pics are attached. Thanks for reading!

5 miles with no coolant is pretty much a death sentence . Maybe do a compression test and if that's good spend as little as possible to get it running /driveable to see if it's still serviceable. My guess would be that the bolt broke first, from the pic it looks like it was cracked.

The pulley stud looks bad. The bearing probably failed first. A slinging belt and bearing probably took out the other parts.
Drill a small reverse bit into the broken bolt. Then use a reverse, drill out bolt. It should come out easily. You could try a small chisel. A chisel may turn it loose too.

Thanks for your reply. I have an E46 325i where the coolant tank failed. I drove it a similar distance to a mechanic. That engine is still running so I still have some hope for this E53. I will do a compression test as you suggest.

Would a head gasket leak or other loss of compression be detected by OBDII? So far I don’t have a check engine light.

Thanks.

The stud shown in the first picture holds the bottom of the tensioner. I will remove it for inspection but it looks ok to me. The picture may be distorted. I am concerned that the bracket with the stud is all the way at its adjustment limit for the lowest amount of tension. I need to check those bolts and the manual to see where it should be positioned.

I was able to get the bolt tip removed easily with a reverse twist drill.

Thanks. DC

Then you got very lucky...Driving 5 miles with low or no coolant and no water pump...when the car is already at temp (like the E53 was) is extremely risky, and more likely than not will result in a cylinder head problem.

Head gasket /warped head pblms often don't show up in a compression test, and they won't typically trigger an error code.

Get the car running and driving as cheaply (within reason) as possible and look for signs of head gasket:

-oil in coolant /coolant in oil
-coolant in cylinders
-coolant smoke /smell in exhaust- particularly at cold startup
-exhaust gas in coolant
-excessive pressure in coolant hoses that may last hours after shut-off

It's a lesson. Run the best oil available. I had an old 305 SB Chevy reach 270+F. It ran a short drive. Fixed a coolant hose and drove it home. Changed the oil and ran it. No issues. A one time event is possible. The next one won't be so good though.

Good luck!

carry spare parts from trusted suppliers
 

Similar story here: When my '66 Chevelle stiil had the 327 SB in it (in '96), I had just installed a used Corvette electric fan in it (replacing the steel flex fan that was on it when I'd just bought it, a few months previously), and had taken it out of the garage for the first time, after putting in new floors and interior upholstery. I had driven it about 20 miles when the fan quit, and the coolant temp rose to 270-275 degrees.

Luckily, I was about a mile from an auto parts store I had gone to before, so I figured I could fix or replace whatever went wrong with the electric fan. I found that the generic used relay (with no amperage markings on it) had melted, so I bought two 30 amp Bosch relays at the store, plus some more coolant.

After hanging out at the auto parts store (and the hamburger joint next door) for about 1.5 hours, I installed the new relay, let some steam out of the radiator (refilling it with about 1/2 gallon coolant) and drove home. The temp was still about 210 at the start, and remained there until I got on the highway, where it fell to 190 (I was using a 160 degree T-stat). At home, I checked the head gaskets for leaks (remember when it was easy to see everything on an engine?), found none, and all was good. I still have that engine on a stand in my garage, minus rocker arms and carburetor, waiting for another project that probably will never come.

That engine, with a '68 block (cast iron), had 462 fuelie heads from '62-64 (also cast iron), with good, new, Fel-Pro head gaskets installed, so there was no warpage, I guess. Gotta love those old SBC's.

I learned to only use "known good" relays after that, from trusted brands, and always have a spare relay in the car/truck with the electric fan installed (my X5 does, and my HHR Panel has several identical relays in the fuse box, that could be swapped in case of need). I haven't checked the Lexus' fusebox for duplicates yet, though.

My two pickup trucks have viscous fans, not electric, so I carry a spare serpentine belt and tensioner in my 2500HD; but, the old GMC only gets a new belt every few years, and since it never goes further than 40 miles from home, I haven't stocked it with spares (it's the wife's truck, with no toolbox onboard.

The accessory belt shredded once about 4 miles from my house. I don't remember exactly why but I had to get home (mostly uphill too) and couldn't wait for a tow. I assumed the head gasket would be toast and basically just accepted my '06 X5 had a good run, but her time was up. Got a new belt, added coolant, and changed the oil. No issues since (20,000+ miles ago).

A quick update from my side (OP). I got a partial shipment of parts and was able to seal up the coolant system. I did a pressure test of the coolant system and it is holding pressure at about 15 psig. This is encouraging for me!

I also flushed out the one coolant channel that exits the block right above the alternator with a small diameter hose connection. I connected all the other coolant hoses and the branch from the upper radiator hose that connects to the that block connection, I sealed the branch with some pinch pliers. I connected a hose to the connection on the block and filled the coolant system through the expansion tank. I did get decent flow through that block connection even with just hydrostatic pressure.

My next step is to add some radiator/coolant flush solution to the system and let it run for a little bit then drain, flush and refill with coolant.

I also tested for OBDII codes with my foxwell scanner. The only code I had associated with engine and transmission is a pending code for high coolant temperature.

I'm still waiting for my replacement fan, so it will be a few days before I take it for a test drive.

Thanks!