Help! Radiator Fan Loose

[blessed]

My radiator fan seems to be shaking and making noise. I've taken the fan off and the trouble seems to be the part that the fan bolts to. Is it the water pump? Anyway, It may be bearings.

Does anyone have an idea what it is exactly and how hard is it to fix?

Steve

[Matthew_McNally]

Steve

what model of Lexus is it buddy?

[AWJ]

Looks like he's rollin a 4.0

On the LS400, that is the 1UZ-FE the coolant fan is hydraulically driven if I remember correctly. Driven by the power steering fluid pressure. Therefore, I beleive that is your power steering pump you are referring to. Although it could be the water pump. Truth is, I haven't worked on the V8 model. Only the inline 6 so until someone else that knows better can come by, I'd suggest getting a shop manual if you really want to fix it yourself. Otherwise, go to your trusted mechanic. I'm 98% sure it is the power steering pump though. Let us know what you find out.

Is it the pulley? Wobbly or what? People have had to rebuild those items in the past.

Good luck.

[blessed]

The modle is a 91 LS 400.

Thanks for the info on the possiablility of it being the power steering pump. I may very well be. As far as what's wobbly: it's not the pully, it's the item that the fan bolts to. I've removed the fan and attempted to remove the item that it bolts to, however, it seems to be part of the "power steering pump" or water pump. Not sure.

Suggestions?

Thanks again for your feedback!

Steve

[AWJ]

Sorry my man - I'll do some digging though. You may want to consult with a mechanic. My inline six is giving warning signs from the water pump, power steering, and transmission. This may not be a good situation for me :( . But I'll fix it. The tranny will have to go to a specialist because I am not gonna even try it in the garage at this point. Not enough tools - or strength for that. But I'll hit up the water pump and power steering. Problem is, they are different on mine and yours. And my fan is just fine. My fan is attatched to the water pump - saw that this weekend. I've got some pics somewhere.

I'll see if I can dig up some info.

[blessed]

Thanks AWJ for any feedback you can help with!

The challenge is the part that the fan physically bolts too. It appears that part's bearings are going out.

Thanks again!

Steve

[AWJ]

I'm almost sure that is your water pump. Replace it along with the serpentine belt. Is there an alternator directly beneath the unit you are referring to? If so, then it is the power steering pump on the 1UZ-FE. Either way, replace it if it is the water pump. If it is the power steering pump, they can be rebuilt - but I've never done it. Although I may have experience with this soon.

[Rich Sweitzer]

Can't speak for all LS-4xx series cars but the water pump and the fan have no connection, at least on my 1991 LS-400. My machine has three radiator cooling fans, two electric mounted in front of the A/C condensor and one "conventional" engine-driven fan with a hydraulic clutch behind the radiator. This "conventional fan is driven by the auxillary drive belt, the same one that drives the power steering pump, the alternator and the air conditioner compressor. It mount to a shaft that sits in a bearing that is in turn mounted in a "fan bracket" bolted to the front of the engine (with 4 bolts, if memory serves) that spans the timing belt cover. (The water pump on this engine is actually driven by the timing belt and is under that cover.) The two electric fans are controlled by a thermostatic switch mounted on the radiator and also by the A/C high pressure switch.

By the way, a friend has a 1993 LS-400 that had the bearing in the fan mounting bracket go bad (freeze up). It apparently made quite a racket just prior to seizing. Hope that this helps.

[LamSV]

Hello Blessed,

Not sure if you find my post too late.

I had a 1994 LS400. Last weekend (long July 4th holidays), I did some retrofit on my radiator fan and I found the outcome very satisfying (at least for me).

My radiator fan (driven by the drive belt) was making a lot of noise when I accelerate (any RPM higher than 2,000). The sound was like a Concorde taking off. It was so embarrasing for an otherwise "silent" Lexus!!! My fan clutch was not working properly (wear and tear) after 9 long years.

However there are so much redundancies in a Lexus (thanks to the great Lexus engineers). There are 2 additional electric fans on the front of the radiator. In my humble opinion, I do not think the radiator fan (with clutch) is really useful to me at this point. Even when new, it will continue to generate noise, drain power from the engine and eventually will fail again because of its mechanical principle.

This is what I did (you can disagree). I completely removed the radiator fan assembly (4 nuts). I used spacers (4 nuts) and the original nuts to tighten the fan pulley back in place. This is absolutely critical - you must ensure that the fan pulley is well tightened, otherwise it will wobble and damage your engine. If you are not sure of what I am talking about here, please go and get a trusted mechanic to do this for you.

I modified (actually very very simple) the electric fans logical circuit. Now my two fans will turn on in Low Speed when I start the car, regardless of the AC on/off condition (original design). The High Speed will be activated when the coolant temperature reaches its preset high point (this is the original design, I did not touch this part). I have no time to explain this simple modification here but all I wanted to say is that I did not add or delete any existing Lexus wiring. I did not use any special tools or gadgets, just some reliable Craftsman (Made in USA) tools.

How is the "new" driving experience? Well, you need to remember that I live in Houston Texas and temperatures are anywhere from 80F to 100F. So far, my coolant temperature indicator (on the dash console) is still showing the middle mark, just like before. So far, I have not seen the 2 electric fans being kicked in at High Speed (meaning that the coolant temperature is not high to need that extra ventilation).

But the most wonderful experience is that I feel my LS400 gaining some additional Horse Power!!! There is the extra quick (tiny weeeny bit more) acceleration, extra responsiveness and certainly my LS400 is quieter (more) than before.

[Myce]

Does anyone know how easy or difficult it is to install a fan bracket on a 1990 LS400? There are two bolts and two nuts, but they appear hard to reach.

[Toneonly]

Try looking at the idler pulley bracket... i just replaced mine. I have a 91 ls400. Thought it was the water pump. Fan rattling... turned out to be the idler pulley...part was about 200 dollaz. Good luck.