kingofcompton

Hello, newbie, looking for advice and really trying to figure out how the belt melted. I just bought a 2000 320 CLK Cab "pre-factory" (the guy bought it for his wife as a toy in 1999 I guess, I'm assuming its prefactory because there's no tape deck OR AUX port in glove, which should be there with all of the factory makes from what I read.

I bought it in Florida and drove it north (1,000 miles) with no issues, other than a check engine about a week later once it got really cold up this way (Philly area). Didn't pass inspection on Friday due to trim #1 and trim #2 errors, which is why check engine was on. Scheduled a euro motorshop to fix this morning.

Anyway, I drove it yesterday about 15 miles (about 10 F outside mind you), I lose power steering and light comes on for battery/alternator. I was about 10 minutes from shop so I called for a pick-up and went right there. About a mile away, a low voltage/ABS light came on, and I lost ability to accelerate, and all power. I got a jump, which got everything going back to normal. and luckily it was mostly downhill to shop so I drop in neutral to leave for tech to check out this morning.

He calls me this morning to say serpentine belt had melted partially and that it should cost $400 to fix damage/replace belt/etc, maybe an extra $30 for water pump. Didn't say anything about trim.

Anyway, anyone have a guess as to why the belt melted? My guess is the belt was original, and used to Florida temp; once it got cold up here, something overcompensated which caused the melt. Suggestions once this belt is replaced (and initial trim issues addressed?)?

stim141

The belt more than likely melted because of a couple of things. The tensioner pulley which is notorious for failing - seized up. If it was the all metal version they go without warning. The harmonic balancer was the non-recalled version and the belt hung up. The secondary free wheeling pulley (at least on the V8's) fall apart but when they go the belt just slips off, trashes the radiator or it wraps around something else which could be the harmonic balancer which is moving by the engine's power and cause it to melt. Anything else like the alternator, compressor or water pump would show signs of failing before they go - like loud noises, etc.

My guess is the tensioner just seized and failed. You get some warning though - grinding noises during startup or a whine during driving.

dlbehrns

the 99 had a tensioner recall. mine was replaced years ago and no problems since.

stim141

I know of a harmonic balancer recall - up to and including 2000 but not the tensioner recall - at least for my 2000 CLK430 there wasn't one and they have the same tensioners - metal pulley. The plastic pulley is the desired version. The harmonic balancer which is what was recalled had issues with the rubber doughnut causing the belt to slip off and really trash the engine. It was a huge problem because the belt would eat into vital pieces of the block's aluminum and those pieces were hugely expensive to replace - think new motor.

His car may not have had the newer version installed even though there was a recall. The idler pulley which does nothing except guilde the belt and the tensioner are wear and tear issues. The idler is plastic and falls apart and the tensioner pulley just seizes or disintegrates. Both with leave you stranded.

rorf

A rubber belt cannot damage an aluminium engine cover - it is the harmonic outer metal part of the pulley which rubs against the timing chain cover and then damaging it.

For a belt to melt then something became stationary - tensioner pulley, idler pulley, aircon, alternator and usually more likely the water pump.

Your exceptionally cold weather after coming up from Florida there is probably no antifreeze in the system or a very weak mixture so therefore water pump seizing up.