jdog0411

Hi all,

Quick dumb question...

My 90 LS400 makes the typical light "chatter" noises from the engine when running, and I am not concerned as I feel that is normal for this car. However, lately it's been making a bit more of a chattering noise coming from directly in front of the car right behind the grill area. It's fairly noticeable.

I thought maybe a pulley or something was starting to go bad, but this doesn't sound like the noise when a bearing in a pulley is going south. So....I grabbed a hold of the radiator cooling fan and there is a lot of play in the fan. I can move the fan back and forth a centimeter or so in each direction, front and back. It's still bolted to the fan clutch and otherwise operates ok, but is this normal? I would think the fan should be bolted down tightly to the fan clutch so there would be no play, but wasn't sure if this was designed in for some reason. If not, that may be the cause for the noise.

Thanks in advance.

jdog0411

Ok....let me rephrase. Can someone with a first gen LS400 check their fan and see if it has some wiggle? Thanks.

etex

It sounds like you may need to replace ylour fan clutch. There is a geletin-like fluid inside the hub that will become less effective over a period of time. Some members have replaced the fluid. A search of the forum will give you more information.

oldskewel

iTrader: (1)

I don't think it is your fan clutch.

I am almost certain that it is your "fan bracket". That is a cast aluminum part about 8" wide that contains the bearing for the cooling fan. The bearing wears out (mine did at 174k on my '91) making noise, wobble, etc. It sounds exactly as you are describing. The bearing itself is not replaceable. The entire "fan bracket" needs to be replaced. Part cost is close to $200, I think, and LOTS of stuff needs to be removed to get to it. Look for the tutorial on T-belt replacement to see the fan bracket and all you need to do to remove it - seems like about half way to a full T-belt replacement.

A quick way to check is to remove the serpentine belt and the fan (just 4 bolts). As I recall, when I removed the fan there was a spoonful or two of metal debris inside the cup - from the bearing deteriorating. It's kind of amazing how it can keep running for so long in such a bad state. But I expect that if you're feeling the amount of play that you are, it will be very obvious once you remove the fan that this is the problem - the fan shaft itself will be wobbly, meaning it is not in the fan clutch. Actually, thinking about it now, you should be able to tell without removing the fan. Just remove the belt and see if there is any side to side (or up-down) play in the fan shaft. There of course should be virtually none. Even 0.1" is way too much. And if you really want to do a quick check, you might be able to just de-tension the belt without completely removing it.

fencera

In my experience with this issue, this is an excellent description of what is likely the problem. Some play is normal, but I would describe it as play, not wiggle. ie the movement should be on one axis-- in this case straight in and out a slight amount.

mikes7ke

iTrader: (1)

I took the fan, clutch, and bracket to get to the timing belt. Three of the fan clutch nuts were only finger tight. There was no play at all in the fan or clutch.

jdog0411

thanks for the responses everyone. I don't think it's the fan clutch or bracket, but it's always a possibility I guess. the car only has 90K miles. Guess I will take the air intake off so I can get to the nuts holding the fan to the fan clutch. My suspicion is that those have come loose over time. I'll report back what I find.

jdog0411

Finally got around to checking out the fan today. Had to take the fan shroud off and then checked the four nuts that hold the fan to the fan clutch. All four were loose. Tightened them up and the fan now has no play in it. I'm hoping that takes care of the majority of the noises coming from the front end of the car.