1995 850 T5 -- Clogged Drain Causes Serpentine Belt Slippage

Post by **atucker1** » 27 Mar 2020, 12:02

Interesting little problem I had, might help anyone else if they have this weird issue too:

After extensive rains here, I had my 1995 850 Turbo parked on a steep slope. When moving from the spot, a few times I momentarily had all the dash lights illuminated and loss of power steering--signs of serpentine belt failure. Checking the hood, though, the belt was still there and after driving for a few minutes on a flatter road the issue went away. The belt is in good condition and was replaced only 30k miles ago.

Later that day, I checked the drain tubes along the top of the firewall--one was plugged, allowing a large amount of water to accumulate in the plastic panel below the windshield on the passenger side. I hypothesized that this water had sloshed onto the serpentine belt when I had pulled out of the parking spot on the hill and made the belt slip. Seemed weird to me, but the most reasonable explanation. I cleaned out the drain tube and the problem didn't occur again, even when pulling out of the same parking spot in the rain.

A few weeks later, I was washing my car and accidentally splashed water up under the hood. Right after that I had the exact same issue, with power steering going out and all the dash lights going off for a minute, and then no issues at all since.

Still seems like a weird explanation to me, but at least based on the two times it happened its been consistent. I would figure the water might be shorting something, except that the power steering was clearly effected too, so it seems like the belt was actually slipping. Anyhow I'm glad it had an easy fix.

Anyone else have another idea, or seen this happen?

Post by **RickHaleParker** » 27 Mar 2020, 14:15

Weak Tensioner. Oil on belt. Worn belt.

Sommerfeldt · Post by **Sommerfeldt** » 28 Mar 2020, 08:21

Any fluid on the belt will be a lubricant while it's there.

Water isn't a great lubricant though, so Rick has a point - the tensioner could be weak, and the belt could be due for a replacement.
If there was oil on it, the problem would probably be more prevalent, and usually it'd be visible as well.

- S