navymech

I have been dealing with what now appears to be a pulley alignment problem on my 1992 300ci. She is not so pretty but has around 180,000 miles accrued, and I rescued her from a sure slow death from someone who would have let it happen. To give you a little background, back in April my radiator literally exploded while I was on the local interstate. Apparently the thermostat decided this was the time to not open, and the pressure built up in the radiator, probably the weakest link in the cooling chain, and I wasnt paying attention to the temp gauge at the moment, and....BOOM!! There was a violent explosion that woke me up pretty fast, and I pulled over on the shoulder, popped the hood, and found that the large nipple at the top right corner of the radiator that receives the large radiator hose coming from the thermostat housing had literally exploded right off the radiator and destroyed the tensioner bad enough for replacement. I went through a long series of belt and tensioner replacements, but no matter what I did, each serpentine belt that I put on would shred in no time. I thought the problem was maybe cheap aftermarket tensioners, so I took my cheap aftermarket tensioner to a machinist buddy at work, and he took metal off the back of the tensioner until the belt wouldnt be up against the rear lip of the plastic pulley so bad, and this idea worked for about 5 straight months, and I thought my problems were over. But...no. Then one day another belt shredded. I replaced it, and another belt shredded. I replaced the tensioner, and another belt shredded. This is when I read your forums and realized that, most likely, my power steering pump pulley may have been impacted from some of the force from the explosion and been pushed back a little. From what I have seen, the belt is jumping one tooth in the rearward direction, but it takes a little while for it to do that. I tried the straight edge method, just making a rough approximation, as my straight edge is not so great, but the power steering pump pulley may be out by somewhere in the neighborhood of 1/16th to 1/8th of an inch....just enough to put some side tension on the belt and make it jump a tooth(taking into consideration the varying thicknesses of the pulley walls). The tensioner I have on there now came from a local junkyard that deals in only Fords (called Rusty Acres...I live in Jacksonville FL). It is used, but the bearing in the pulley is really nice and almost no play at all. The pulley on this tensioner has no lips on it, as this is a dealer part, where my aftermarket tensioner pulley had lips on it. So, now it looks like I have to take the pulley off of the power steering pump and reposition it back on, or at least pull it out just a bit, maybe 1/16th inch or so, and put a new belt on and check it. The one I have right now is about half gone on the rearward side, and must be replaced. I have never had a belt alignment problem before, and welcome everyone's thoughts, ideas, and advice. I have been using my 2003 Taurus as my work transportation instead of my truck, as I took her off the road 3 weeks back, and I am trying to get her back on it again. It was my main goal to get 200,000 miles out of this truck, but I realize now that I can probably take it well beyond that.

Scraptor

Check for wobble in the waterpump pulley. Also the smog pump seized and ate my belt awhile back.
That Rad exploding sounds weird for just over heating.

ymeski56

I had a Thermostat slam shut & the pressure blew the side tank out of a perfectly good radiator.

Never saw a gauge peg so far over & so fast. I thought someone shot at me, it was so loud when it blew.

navymech

This one was pretty new to me, and had never happened like this before. It was sudden and very violent, and fairly powerful. My thermostat had never shown any pattern of sticking closed like this before, and the truck had not been overheating, so I was just watching the road and driving, and suddenly it went kaboom. If I had looked down at the temp gauge I would have seen the needle pegged on the hot side. Strangely enough, I didnt see steam or smell anything before this happened. I had to replace the radiator, the tensioner, the belt, the thermostat, the thermostat housing (it was corroded bad), and the housing gasket. It looks like, now, that there is just enough pulley misalignment to cause the belt to jump once, but not right away. It might not happen today, but maybe tomorrow or the following day. But it does and will happen, so I must effect repairs somehow. I bet that explosion caught you offguard like just like me.

Scraptor

Thought about it my truck ate belts, then the smog pump stuck, I bypassed that wiath a shorter belt
( no smog check here) and it still chewed one row off the belt, then I swapped in an electric fan, and destroyed the waterpump taking off the fan, still ate one row off the belt, then I had a belt jump off in traffic, about half a block from a Napa store, bought a new gates belt, problem solved . I never heard
About the p s pump pulley moving, but anythings possible.