Barticus35

Hi all,
I'm new to this but thought I might be able to get a little help on my car. I have a 1998 Lexus GS400. Absolutely love this car and I have the mileage to prove it. Currently at 357000+. Anyway, I do a little mechanic work just to save a few bucks like everyone else. Today my car was making a knocking noise. When I popped the hood I could see the assumed source of the noise. It was coming from the front of the engine and I could visibly see one of the pulleys kind of wobbling. I was about an hour from home and no real way to avoid driving home so I did. While driving home I felt the steering become difficult and the battery indicator light come on. No big deal I thought. Probably the serpentine belt broke. Which it did. However, I don't think that it just broke as I've replaced several serpentine belts before, (not on this car) and they usually are pretty shredded when they fail. Not here. There is a fair amount of what looks like melted rubber from the belt on most pulleys. I'm assuming that the Fan pulley froze and thus prevented the belt from going around the pulleys as it should and more or less just melted through and fell off. Replacing the belt is a snap, but it that fan pulley is frozen, I'll have the same problem all over again. Here's my question. Can the fan freeze up like that and, as much as I hate to admit it, is the fan pulley simply the waterpump freezing or locking up? There's no antifreeze spillage and my gage didn't indicate any excessive heat build up. Has anyone else experienced this and if so, how do I know if I need to replace the water pump?


Looking forward to your helpful responses.

lextout

wow just curious does the gs have the original engine and tranny? if yes then im amazed.

iToaster

There is no fan pulley on the GS400, it uses electric fans. The water pump is run off of the timing belt, not the serpentine belt, and usually should be replaced alongside the timing belt (because it's convenient to do it then) every 90k or so miles. There are a few idler pulleys, the tensioner pulley, and of course any of the belt driven accessories that could have seized up. They are generally fairly straightforward to replace once you have identified which one has failed.

Barticus35

Hi all,
in response to lextout, yes, it is the original motor and Tranny. Exactly what's been done, I'm not sure as I bought the car with over 200K miles on it, but they are both original.
In response to itoaster, the bad part is called a Fan Pulley Bracket. From what I can tell it's nothing more than an extra pulley for the serpentine belt to go around. No fluid runs through it, no fan is attached, but it's there and the bearing seized up on it. I purchased a new one and installing it is fairly straight forward, EXCEPT, that I had to remove the timing belt covers to remove that bracket. That of course let me see the timing belt, which is in rough shape. I'm replacing it now but have run into a hiccup. To get the lower cover timing belt off of the block, yes, I've removed the crank pulley at this point, I have to remove the alternator. To remove the alternator I have to remove the power steering (PS) pump, but I can't figure out how to remove it. The alternator just bumps against the edge of the PS pulley and won't clear it. I've removed a nut on the ps pump but can't seem to find anymore and it won't budge. This is a case where I should have taken the car to a qualified mechanic, but since I didn't, I'm in a pinch here. Any tips on how to remove the PS pump will be appreciated.


Thank you.

GS400V8

iTrader: (4)

To remove the alternator you must remove the power steering pump's pully. Stick a small wrench through one of the cut opening on the power steering's pulley. This will lock it against the engine when you are turning the nut that holds the pulley on. Come right off, then you can to the opposite when you put it back on. There is another way of positioning a wrench in there on a different opening in the pulley, so it doesn't spin when you are tightening the pulley nut back on.

Barticus35

Hi all,
Thank you for the suggestion of removing the PS pump pulley. I couldn't get it off using a wrench and a bar in the holes on the pulley, I did however get it off using an impact wrench. Worked well. Same goes for the Crank pulley bolt..
All done, and I must admit, I was scared to turn the key and start it as this is the first one I've done. Worked well though and I'm glad it's done. Thank you for the suggestions.