Help Please -03 LC - Loss of Power and Loud Fan

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10 Year
Joined
Oct 25, 2011
Threads
7
Messages
17
Hello All,
Thanks in advance for your help.
My 2003 LC (355,000 miles) is suddenly having an issue and we can't figure it out.
The number one issue is a serious loss of power, especially when going uphill. At the same time the fan becomes very loud.
I'm not very knowledgeable about engines, etc., so forgive me if I use the wrong terminology... but I will do my best to give you what info I have.
At first I it felt like the beginning of something that had happened years ago, where the c clip near the axle popped out causing the splines to separate and eventually strip out completely.
My mechanic checked and said the c clips are in, so he didn't think that was the issue.
He thought the loss of power was an exhaust issue, especially because she's been throwing the 0420 code for awhile. But the muffler shop said he tested the cats and there was no backpressure, so they were clear.
I then took it to the transmission shop. Out of nowhere, he pulled a code that suggested it was a coil and nothing indicating any transmission issues. So my mechanic flipped a set of coils and plugs and since the code moved he replaced that coil.
Now we are back to where we started....A loud Fan and no balls.
I've had her for 20+ years and put 330k of her miles on her driving my kid all of the place, nearly all on the highway. These last few years though, I've only driven her about 5k a year.
From 2022 to the beginning of 2024 I've done the following:
Aisin Timing belt kit
Aisin Water pump
Crank Seals
Eyelet Pulley
Cam Seals
A/C Compressor
Condenser
OEM Valve cover gasket
OEM Starter
OEM Serpentine Belt
OEM Fan clutch bracket
Misc Water hoses
KYB Front and rear shocks
Denso Alternator
Fuel Filler Neck
Fuel pump
Radiator

If any of you have any suggestions or questions, please let me know.
Thanks

BTW, I'm in Southern California.
 
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Make sure the fan clutch is OEM or aisin. Others make a lod sound all times. Also check for the cooling fins on radiator and ac condenser.. make sure those are not clogged.
 
Trunk Monkey said:
Get a cheap bluetooth code reader and pull the codes yourself. But, your description sounds like a coil pack. Is it intermittent or constant?
Click to expand...
Thanks for the reply @Trunk Monkey . I have a code reader, but I haven't driven it enough since they replaced the coil pack, to get codes yet.
Let me clarify a little. For as long as I can remember, she has driven amazingly. The only major issue she had was the Cats. A few weeks ago I noticed the power loss and the fan becoming super loud. It felt like a transmission issue or that issue I mentioned before where the axel came apart and stripped the splines. My mechanic and my muffler shop said I should have a transmission guy take a look, so i dropped it off. When he called me the next day, he said that he got a code (i think it was 0304) and suspected it was a coil pack. He suggested I resolve that first and see what it feels like after. When I picked the truck up it was noticeably shaky and felt like it was missing. My mechanic pressure tested the cylinder and said it was fine. He then swapped the coil pack to a different cylinder to see if the code moved and it did, so he replaced the coil pack. When I drove the truck after, the shaking and missing was gone, but it still didn't have it's power back and the fan is still super loud when I try to accelerate.
I'm trying to not drive it because I live in a hilly area and am worried its gonna blow.
I'm not really sure how to answer your question because it feels like the loss power and fan noise happens when I push the gas and accelerate. I guess that means intermittent.
 
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nissanh said:
Make sure the fan clutch is OEM or aisin. Others make a lod sound all times. Also check for the cooling fins on radiator and ac condenser.. make sure those are not clogged.
Click to expand...
Thanks for your reply @nissanh. I will double check the fan clutch. But I'm pretty sure its OEM. When we did all that work above, I insisted on OEM parts. The timing belt kit / Water Pump was Aisin.
I forgot to mention that I also replaced the radiator, but I will check both of the fins and report back.
 
Loss of power and a loud fan tell me that problem could be a fan clutch, like mentioned above. Happened to a friend of mine and that's what it ended up being.
Try spinning the fan with the engine off. There should be some resistance, but not much. In my friend's case, his fan was very hard to spin by hand.
 
imperium said:
Loss of power and a loud fan tell me that problem could be a fan clutch, like mentioned above. Happened to a friend of mine and that's what it ended up being.
Try spinning the fan with the engine off. There should be some resistance, but not much. In my friend's case, his fan was very hard to spin by hand.
Click to expand...
Thanks for the reply @imperium. I'll be home on Wednesday. I'll check and report back. Thanks.
 
A sort of rule of thumb is if the car won't go over 45 mph, a cat is clogged. If the transmission is slipping, you will see the RPMs increase without the car speeding up. A good way to test if the front splines are stripped again is to lock up the center diff with the button and drive it, If it drives normal, then you were loosing all the power up front on a stripped out axle flange. Coil packs usually feel like a miss upon acceleration, sounds like you fixed that.

When's the last time you changed out your air filter? A really clogged air filter will make it run like crap. You have to be sure it is not throwing a code first and foremost. No codes eliminates many things and points to a mechanical issue instead of a computer management issue.
 
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