mystery noise

Joined
Dec 7, 2002
Messages
1,639
I finally got my 1986 FJ60 (2F) running. I have noticed a strange engine noise when cruising on the interstate (running about 2500 rpm). It sounds as if the engine speed is increasing (it hums or "whines" louder intermittantly). It will make this sound off and on about every 2 minutes and it lasts 20 o 30 seconds. None of the gauges move (oil pressure, volt meter, tach, heat gauge) and there is no change in speed or engine performance. If I let off on the gas and coast with the clutch disengaged, the sound immedialtely is gone. Could it be the radiator fan running off and on? Or the air flow into the air cleaner being switched from the outside to the manifold?
 

2mbb

SILVER Star
 
 
Joined
Sep 1, 2003
Messages
4,693
Location
WC, CA
what you've described sounds like the radiator fan. It has a silicone oil clutch that engages the fan at a certain temperature. The increased air flow cools and the fan disengages. And so on. When the fan is engaged, it's speed is the same as the engine. At 3000 rpm it's faster and a lot louder than it is at idle.
 
Joined
Dec 7, 2002
Messages
1,639
Is it going bad?

I wonder if the fan clutch is going bad then. It doesn't make sense for the thing to be engaging at 60 mph. Any ideas how to test the thing?
 

Landpimp

GOLD Star
 
 
Joined
Mar 14, 2003
Messages
16,146
Location
Gig Harbor WA
fan clutch normaly would not lock up on the hiway.

carb cooling fan should only run when you turn off the motor, not when running.
 

b56tc

 
Joined
Oct 20, 2005
Messages
196
pimp, do you actually currently have possession of that cruiser fleet? where on earth do you keep them all? I want to learn. And see a picture of your garage!
very cool.
 

Landpimp

GOLD Star
 
 
Joined
Mar 14, 2003
Messages
16,146
Location
Gig Harbor WA
yes I have them all. 13 total.

b56tc said:
pimp, do you actually currently have possession of that cruiser fleet? where on earth do you keep them all? I want to learn. And see a picture of your garage!
very cool.
 
Joined
Jul 31, 2005
Messages
127
Location
North Texas
You Are My Hero!!!! :bounce:

I Don't Think My Wife Would Go For Anything Over 2 Or 3 Cruisers. And I Am Having A Herd Time Convincing Her Of That. :crybaby:

13- You Cruiser Stud!!!!!!!!!



YETIMAM
 

b56tc

 
Joined
Oct 20, 2005
Messages
196
yeah yeti I agree.
I have not yet found out how to get more than 2 of the same vehicle without undue marital stress (if you have 2, one is yours, one is hers. Even if she doesn't drive a manual).
What is the rest of your fleet - as if you need anything else?
I'm just enjoying living vicariously through someone in LC heaven.
 
Joined
Jul 31, 2005
Messages
127
Location
North Texas
Ya I Just Narrowed My Fleet Down To My Dd 85 Fj60, I Just Sold A 60 Last Thursday. My Wife Has Baby Feaver. So We Are Thinning Things Out. My Wife Has A Wrx. She Likes A Little Smaller Car For Her Dd. After We Do The Kiddo' Thing We Plan On Adding A 40, And Mybe An Iron Pig. Well Those Are The Two On My List. If The Right Price Came Up I Would Add One Sooner. I Have An Extra 2f So That Helps Me With Adding Another Rig.

Yeti
 

Dr. John

SILVER Star
 
Joined
Oct 27, 2005
Messages
94
Location
West Columbia, SC
My rad fan did that for years but I haven't noticed it lately...Hmmm. There was a thread on the old TLCA list years ago about changing out the silicon fluid in the clutch. Lighter weight fluid would make the engagement less abrupt.

87 60
 

Pluton

 
Joined
Oct 12, 2004
Messages
418
phourwheel'in said:
I'll bet it is the carb cooling fan, coming on and off.
I doubt the carb fan in a 60 would be audible under the engine/driving noise at 60 mph.
 
Joined
Dec 7, 2002
Messages
1,639
Can't be carb fan

I agree with what landpimp says about the carb fan. When I coast, the noise goes away, which would not happen with the carb fan. Again, any more ideas on the radiator fan?
 

Landpimp

GOLD Star
 
 
Joined
Mar 14, 2003
Messages
16,146
Location
Gig Harbor WA
I would say its also not the fan clutch, as you say it goes away when you coast and put in the clutch.

kinda sounds like its in the clutch or trany.........but that is only lasts 20-30 seconds would make me think its not clutch or trany related.

once warm the air flow to the air cleaner should not change, the little flaper opens at a set tempature.

I am stumped..........but there is something in the back of my mind.........I just can't pull it up ;)

Heartworm said:
I agree with what landpimp says about the carb fan. When I coast, the noise goes away, which would not happen with the carb fan. Again, any more ideas on the radiator fan?
 

60wag

SILVER Star
 
 
Joined
Jun 25, 2003
Messages
1,931
Location
Boulder, CO
I still think is the fan spinning up and free wheeling. Mine does that on the highway. I think its normal. When the clutch fails, it free wheels all the time doesn't it?
 
Joined
Oct 22, 2004
Messages
2,973
Location
Clemson, SC
could it be a vaccuum leak? I know I had one on my 40 around the base of my carb....cruiser still ran decent, and ya only heard the noise when you applied the gas pedal. Could be 2 different sounds we are talkin about...lol.
 
Joined
Dec 7, 2002
Messages
1,639
Still hoping it is the fan

Landpimp: Dropping the RPMs on the motor from 2500 to 650 would certainly slow the radiator fan considerably and thus the noise I am hearing. The rig idles very smoothly so I am not leaning toward a vacuum leak. There is no shuddering in the driveline when the noise comes on and the RPMs don't change. Incidentally, I tried to choke the motor down by puttin my hand over the plastic air intake tube without success. I had just driven 17 highway miles so the motor was up to temperature. Maybe my HAC is acting weird?
 

Landpimp

GOLD Star
 
 
Joined
Mar 14, 2003
Messages
16,146
Location
Gig Harbor WA
it "could" be the fan clutch I suppose......I just have never had any of mine kick on when on the highway or if they did I couldn't hear them kick on.

Heartworm said:
Landpimp: Dropping the RPMs on the motor from 2500 to 650 would certainly slow the radiator fan considerably and thus the noise I am hearing. The rig idles very smoothly so I am not leaning toward a vacuum leak. There is no shuddering in the driveline when the noise comes on and the RPMs don't change. Incidentally, I tried to choke the motor down by puttin my hand over the plastic air intake tube without success. I had just driven 17 highway miles so the motor was up to temperature. Maybe my HAC is acting weird?
 
Top Bottom