I saw this http://http://www.ffdynamics.com/pro...ricfankits.htm and it seems to say electric makes less noise.

Idiot question here, but bear with me....when I accelerate, I hear a hard whir from the engine compartment....isn't that the clutch fan that I'm hearing?

I know Lyon went electric and he says it is superquiet. Unless I am missing something, I was hoping to convert to electric fan and measure the noise difference and post it back here.

 

Just a couple of thoughts:
- everybody knows there's a muffler on the exhaust to keep the engine quiet. But the intake design is important too - there's a lot of noise from the intake. The air filter box is designed to cut down on the noise - I'm sure that the cold-air intake/cone filters increase noise from the intake. Make sure that the intake system is in good condition.
- the tailpipe must extend beyond the body, there's lots of posts of people with excess interior noise from the tailpipe being too short.
- if you have a manual transmission, there is an inner (lower) boot for the shifter handle, that is usually deteriorated to the point of being useless, letting in a lot of engine/transmission/road noise. If you pull up the (visible) shifter boot, then you can see the lower boot - it seals between the body tunnel to the shifter handle. I believe these are no longer available, but one from a TJ or YJ (I forget which) fits not too bad, just need to make new holes for self-tapping screws. If you need the part number, I can look it up.
- bad motor or transmission mounts will increase noise a lot. The left motor mount gets hard, because it is exposed to the heat from the exhaust manifold.
- any hole, no matter how small, will let in significant noise. Make sure all the holes in the firewall are closed up with caulking.
- I normally can't hear the engine cooling fan, unless I'm pulling my trailer. I replaced the fan clutch recently, didn't make it louder. Make sure you get the correct clutch, some have installed a heavy-duty V-8 ZJ clutch, and reported it sounds like an airplane taking off (and costs 2-3 MPG). Mine was a real nuisance to replace (I think my rad is 3-core, thus thicker than stock), I had to have the fan off the clutch, move the fan and clutch and shroud into place all at once, then assemble it all up. Not fun, when your hands are a big as mine.

And one question: How do you get rid of the squeak from the back seat upper latches? If nobody is in the back seat, every time I hit a bump it squeaks, drives me nuts now that I'm listening for it.

 

From my end it's hard to tell with 100% certainty that the noise u hear is the roar of the clutch fan and not something else. Most vehicles are reasonably quiet around town (+/-30mph) and noise goes up at highway speeds (+/-60mph). At highway speeds, no fans of any kind should be needed....if the cooling system is functioning correctly....there's plenty of air moving thru the rad at highway speeds to keep things cool.

What I'm saying is, if it is belt driven fan noise that u hear and the fan clutch is functioning correctly (key word is correctly) maybe the motor is running warm enough to engage the fan clutch fully (the roar). If the motor is running warm enough this time of year (cool/cold ambient temps) to engage the fan clutch, maybe, just maybe, there are issues with other cooling system components (not performing top notch).

If the motor is running warm, not necessarily overheating, but at the upper end of normal temp range, u can bet the fan clutch will be fully engaged, doing its job, drawing max air, thus making noise. U can also bet, that efans will be roaring to cool the motor. If u can't hear efans when they are on......they are probably toy fans and won't come anywhere close to properly cooling the motor, especially 6 months from now.

The clutch fan is really a clever invention that places virtually no load on the motor when free wheeling (functioning properly) and automatically senses temp rise and gradually (variable speed) increases air flow thru the rad as needed. It just shouldn't roar this time of year (except for cold start-up). I've experimented with efans (not on the XJ).......give me a clutch fan any day of the week.....but experimentation is a good thing and efans may work well for u.

 

I think the hood liner would be a big help. I was amazed too at what new carpet/padding did for my Wrangler when I had it. Maybe some thicker padding/backer behind our stock carpets would kill lots of noise.

btw: Thanks for serving, I'm glad you are home safe.

 

This really got me very curious and did it on the fly on my way home from work. I know this might not be that accurate but i downloaded a decibel meter app and wanted to see how it is in my truck. I mean, i know my truck is actually not bad when it comes to noise levels..anywho..my truck on the highway doing 60mph i was getting about 55-57dB...at idle it was about 43.7db...not bad

 

Interesting. I get 60db at idle with my meter and 67db at 55mph and then about 69db at 70mph right now.

I am going to take a look at the door seals tomorrow with the vaseline trick--that is pretty clever!

I'm also shopping for hoodliners now. There is a huge price range. Dynomat can be had for $48 on amazon. but some of the higher ends go to $250.

I keep hearing "you get what you pay for," but does $250 make that big of a difference?

I will check the fans tomorrow too.

Thanks to all for your help. I am really excited to cut the noise down.

 

This worked well for my efan conversion. The second fan just kicks in with the first. http://www.angelfire.com/my/fan/electric.html Is there any rustproofing under the body? That might deaden the sound in the cabin a bit.

 

A thought on electric fans versus mechanical clutch fans - aside from what everyone has already mentioned, may have a different blade design. The square shape of the blades on the mechanical fan is well known to be noisy, but easy to make with steel, and therefore more durable and cheap. A lot of electric fans' plastic blades are molded into an almost cup-like shape. If you take a look around at computer fans you will quickly spot the difference between performance air pushers and those that are 30 dBa or less.

 

Just a thought here when talking about a hoodliner. Most of my vehicles have some areas "cut out" to allow for clearance of certain items. So when shopping, think about the thickness and if it could make contact somewhere it shouldn't (when installed). Seems like there's a lot of opinion but I just don't see where a hoodliner would cut down enough to make much difference. The firewall (since it's located right beside the cockpit) might be a different story. Also the footwell areas. You could simply locate a specialist and have them give you a quote on what they would do, then take their quote and see what you could do yourself. Might give you more ideas.

 

I converted to dual stock auxillary fans because I was tired of the noises the mechanical fan makes. It's rather annoying sounding like a school bus going down the road. There's no need for it. And I've replaced them and had new ones go bad in no time. My fans cycle very seldom especially running a 180 t-stat so it WILL keep the noise down longer which is his ultimate goal. Yeah, the mechanical fan may be quieter at certain times and loud on start up but an electric fan which is not needed to run at all is completely silent. Just my .02

 

We likewise run a 180 stat.....maybe that has something to do with less roar from the clutch fan (less engagement). Our fan clutch was recently replaced and is not noisy until ambient temps start to reach triple digits. Seldom does the stock efan kick in, especially this time of year, but when it does (defrost engages compressor), u can definitely hear the efan. '00-'01 XJ efan only turns on at 218F coolant temp, not when compressor engages. There have been numerous posts about efan cycling on/off (noise can be heard) in defrost mode, but that's a different story (low refrigerant).

 

I consider my XJ to be quiet compared to my current DD , An the YJ and TJ that I owned. If you want to make it more quiet inside pull out the headliner, door panels, side panels, and carpet then go to town with Dynamat

 

I'm not going to go to this extreme, BUT (and I'm probably jinxing myself) - if the motor ever had to come out AND/OR the dash removed, I'd think long and hard about spraying the motor side of the firewall/tranny tunnel with Lizard Skin (or something similar). I'd then apply Dynamat (or something similar) to the cabin side of the firewall as well as over the tranny hump. Hardest places to insulate but also the noisiest places, I would think.

 

I have thought about this extreme, and if I did have to expose that part of the firewall, I'd do it. Here's a question though for the dynamat folks: Can you get it to stick on top of lizard skin or raptor skin? I thought you needed clean metal to stick dynamat on?

Thanks to all for the great advice. This is going to work I know it.

 

How many rolls did that take? That is a crazy cheap price if it works even 50% of what dynomat does. I did dynomat in my first XJ ( 10 years ago ) and it wa more than my lift cost??!!!??! If that stuff works that well I am very interested!