Start up roar

[HuyFZJ80]

Recently purchased my 80, and every time I’ve cold started it, the engine/fan roars for around 5 seconds or so. It’s quite loud, but maybe that’s just me getting used to driving smaller stock vehicles my whole life.

Just wanted to know, is this normal for the 80 to “roar”, or is this something indicative of fan clutch failure? Anything is should consider to depress the roar a bit? Thanks y’all!

 

[OffRoadScott]

Recently purchased my 80, and every time I’ve cold started it, the engine/fan roars for around 5 seconds or so. It’s quite loud, but maybe that’s just me getting used to driving smaller stock vehicles my whole life.

Just wanted to know, is this normal for the 80 to “roar”, or is this something indicative of fan clutch failure? Anything is should consider to depress the roar a bit? Thanks y’all!

Completely normal

 

[HuyFZJ80]

Would doing the blue hub fan clutch mod help lower the noise? I’m considering either swapping it out as I think it’s original with a blue hub, or maybe just changing the silicon/oil inside.

 

[ZackR]

Let er roar

Completely normal and indicates the fan clutch and cold start high idle are both working as they should.

 

[toy_tek]

If you don't hear a roar at startup, that's when you need to be concerned.

 

[HuyFZJ80]

Thanks fellas!

 

[OffRoadScott]

Would doing the blue hub fan clutch mod help lower the noise? I’m considering either swapping it out as I think it’s original with a blue hub, or maybe just changing the silicon/oil inside.

No as I have the blue clutch in mine and it is loud as well.

 

[duece71]

Must be different for diesels….orange fan clutch from Land Tank, no Lions roar.

 

[mudgudgeon]

Just wanted to know, is this normal for the 80 to “roar”, or is this something indicative of fan clutch failure?

Quite the opposite. If there's no roar at start up, clutch may not be at full function.

 

[80t0ylc]

Thanks fellas!

Just an FYI. A warm start may not produce a roar at start up. The roar is caused by the high-speed idle plus the oil in the fan clutch has not been dispersed. So at a cold start up, the clutch temporarily “resembles” a seized clutch, but it really isn’t. Once the oil distributes and the RPMs come down it quiets to normal. Depending how long the engine has been off, will determine if it roars on a warm start. Several years ago, my original fan clutch seized on me. It roared all the time and was louder than normal at idle. If it does seize, you will want to replace it ASAP because running the engine for an extended period of time like that stresses your water pump and could cause it to fail.

Edit: Please see post# 29 for correction and clarification.

 

[mudgudgeon]

My work truck roars loud on start up at the moment with the freezing temps.
Quiets down over about 10-15 seconds

 

[HuyFZJ80]

Just an FYI. A warm start may not produce a roar at start up. The roar is caused by the high-speed idle plus the oil in the fan clutch has not been dispersed. So at a cold start up, the clutch temporarily “resembles” a seized clutch, but it really isn’t. Once the oil distributes and the RPMs come down it quiets to normal. Depending how long the engine has been off, will determine if it roars on a warm start. Several years ago, my original fan clutch seized on me. It roared all the time and was louder than normal at idle. If it does seize, you will want to replace it ASAP because running the engine for an extended period of time like that stresses your water pump and could cause it to fail.

Thanks for that! Definitely only roars on cold start. She starts without the roar when warm.

 

[80t0ylc]

My work truck roars loud on start up at the moment with the freezing temps.
Quiets down over about 10-15 seconds

I thought it was summer down there now. Don’t you live in Australia?

 

[BILT4ME]

Just an FYI. A warm start may not produce a roar at start up. The roar is caused by the high-speed idle plus the oil in the fan clutch has not been dispersed. So at a cold start up, the clutch temporarily “resembles” a seized clutch, but it really isn’t. Once the oil distributes and the RPMs come down it quiets to normal. Depending how long the engine has been off, will determine if it roars on a warm start. Several years ago, my original fan clutch seized on me. It roared all the time and was louder than normal at idle. If it does seize, you will want to replace it ASAP because running the engine for an extended period of time like that stresses your water pump and could cause it to fail.

How does this stress your water pump and cause it to fail? Please explain the cause.

You realize that all cars and trucks before 1975 (approx) had fans without clutches.
These were installed as a fuel and HP saving measure, not because the water pump failed.

 

[davidp14]

mine recently quit roaring on startup and I noticed higher running temps. A faulty asin fan clutch from rock auto was to blame. I put in a new midified blue hub from land tank and my roar is back.

long way of saying roar = good. no roar = bad.

 

[cruzinfj1]

How does this stress your water pump and cause it to fail? Please explain the cause.

You realize that all cars and trucks before 1975 (approx) had fans without clutches.
These were installed as a fuel and HP saving measure, not because the water pump failed.

This made me laugh and shake my head too..... this whole thread actually, but some things are better just to scroll on by.....

 

[80t0ylc]

How does this stress your water pump and cause it to fail? Please explain the cause.

You realize that all cars and trucks before 1975 (approx) had fans without clutches.
These were installed as a fuel and HP saving measure, not because the water pump failed.

If you remember, tools r us, he was assisting me troubleshooting a fan clutch one time, and we diagnosed a seized clutch. He mentioned that replacing the clutch ASAP was a good idea. And he explained to me why: when the clutch is fully engaged, there’s more vibration and strain on the water pump because of the vibration. That wouldn’t be so if there was no weight of a fan clutch on the water pump shaft, but since there is, plus a bigger and heavier fan it is unnecessary to have the fan engaged all the time. That is one benefit of having a fan clutch. And it makes sense to me. If you don’t mind, i’m just trying to share that information. The fuel savings and HP is true, but is a secondary and less important issue.
Edit: Please see post# 29 for correction and clarification.

 

[mudgudgeon]

The fuel savings and HP is true, but is a secondary and less important issue.

It's 100% the primary purpose of a fan clutch.

An engine fan saps a lot of horsepower. To overcome any resistance, you're burning fuel.
Running an engine fan full time absolutely burns more fuel.

Swapping to a smaller bladed fan that provides less resistance is a hot rodders trick to increase available power from any engine from way way way back

 

[BILT4ME]

If you remember, tools r us, he was assisting me troubleshooting a fan clutch one time, and we diagnosed a seized clutch. He mentioned that replacing the clutch ASAP was a good idea. And he explained to me why: when the clutch is fully engaged, there’s more vibration and strain on the water pump because of the vibration. That wouldn’t be so if there was no weight of a fan clutch on the water pump shaft, but since there is, plus a bigger and heavier fan it is unnecessary to have the fan engaged all the time. That is one benefit of having a fan clutch. And it makes sense to me. If you don’t mind, i’m just trying to share that information. The fuel savings and HP is true, but is a secondary and less important issue.

While I highly respect the thoughts and opinions of tools r us, I believe there is more to the story.

If the bearing within the fan clutch is failing, then, yes, there is more vibration and can cause a water pump bearing to fail.

However, if it is just the actuation of the fan clutch and it is locked or on continuously, it will just cause more drag. No more vibration than any other time.

Details are important and that is a key part of diagnostics and troubleshooting.

 

[80t0ylc]

It's 100% the primary purpose of a fan clutch.

An engine fan saps a lot of horsepower. To overcome any resistance, you're burning fuel.
Running an engine fan full time absolutely burns more fuel.

Swapping to a smaller bladed fan that provides less resistance is a hot rodders trick to increase available power from any engine from way way way back

I know that’s what we’re told, but for all its importance, with an engine that’s designed to have a fan clutch, when it’s not operating puts unnecessary and additional stress on an essential component (water pump) and if neglected could cause engine to fail. That, IMHO, prioritizes things a little differently.
Edit: Please see post# 29 for correction and clarification.