Power loss and roaring sound

[stationjj]

Today I went on a 35 mile trip. As I arrived I starting noticing lose of power. At the time no big deal. Last time I had that issue I replaced fuel filter and I was good.

On the way home I noticed another issue a periodic roaring sound. A roaring sound almost like when air filter is off or loose, but not as loud. The roaring sounded like its coming from engine and the rear as well. I am not noticing any vibration. The noise comes and goes, and if I reduce my speed noise will reduce and stop.

When I got home. I did a quick check on fluids, belts, air filter housing, and exhaust under the truck. I wasn't able to detect anything. I did some research concerning roaring noises and power lose. I didn't find anything that seemed relevant to what I am experiencing. A few suggestions I got were rear fuel sock, fuel filter, and maybe flex plate issues? I plan to replace fuel filter this week. Obviously I think the roaring noise and power lose are related. The roaring noise has me confused.

Also I am running an electric fuel pump. Could the fuel pump be dying?

I am looking for some direction or ideas.

Thank You,

stationjj

 

[Rustyshackelford]

Could it be the fan?
When the motor on my 89 suburban got hot, the fan would kick on. It would give a noticeable power loss and create a roaring sound.

 

[stationjj]

Thanks for your input. That is something to consider. I do have an issue were the heater fuse melted on the fuse panel. I think it's causing an issue with my exciter wire on Alt 1.

Maybe it's related as well? I have been driving truck for weeks with Alt 1 issues. I didn't think it was related at first. I could be wrong? Will be working on heater fuse issue on Tuesday.

Thanks,

John

 

[cucvrus]

I would go for the fan clutch assembly on the front of the engine. That has no relation to the fuse issue but if you check the radiator fan and it is loose and hard to turn it is on its way out. They are inexpensive and with 4 - 5/16 bolts and 4 5/16" nuts (1/2" socket and 1/2" wrench) they are easy to change. The heater light I am guessing is in relation to the heater fan control switch behind the instrument cluster cover. That is also an easy inexpensive fix. If that plug on the back of the switch is melted it is making a poor connection and creating heat. Good news is any old GM vehicle used the same plug on the blower switch. I snag some when I visit the upullit. Good luck and keep us in the loop. I am interested in your findings.

 

[welpro222]

radiator fan and it is loose and hard to turn it is on its way out.

Did you mean loose and easy to turn?

 

[armytruck63]

This is how I was taught to test a fan clutch: with the engine turned off, try to spin the cooling fan by hand. You should feel some resistance, the fan should not spin freely nor be locked up. You can also try to wiggle the fan towards the engine or radiator to check for looseness, which could either be the fan clutch or the water pump.

It sounds like your engine started getting a little hot and the fan clutch kicked in like it was designed to do.

 

[stationjj]

Thanks everyone. Update on where I am. I was able to drive it more today. When the issues started yesterday it was raining hard.

I drove the truck 10-15 miles today. I had lose of power and a roaring sound from engine. The lose of power is noticeable, but not the same when I had fuel filter issues. As per Cucvrus I did check the fan clutch. I had some resistance. It wouldn't move freely, but I don't think it's suppose too? I could move it, but not with some extra force. When I moved the fan it wouldn't move far. Didn't hear roaring sound in rear. Mystery? Guessing rain threw me off?

I did some further research. I am leaning more towards fan clutch issue. What's does everyone think?

Next questions, How long can I run truck with fan clutch going out? Fan stops running eventually and overheating?
Also from research replacement seems fairly easy. I ask with regard to my auto mechanic experience.

Thanks You!

stationjj

 

[cucvrus]

You could run it 10 minutes or 10 years with a bad clutch fan. That is unpredictable. It could fail at any moment or not fail. If it is bad replace it to avoid the further expense of the results of failure. They can be more expensive results. Good Luck. I am just trying to help.

 

[Coffey1]

Butch had same symptoms on his 944.
Roaring and no power.
His center carrier bearing was binding up.
He got rid of it and put a one piece drive shaft in.
He said it made a huge difference.
Just a thought.

 

[dependable]

Fan clutch should have some resistance, but you should be able to move it all the way around with very little force. Worst case scenario; it fails and sends the fan though your radiator.

 

[stationjj]

The common census points towards the fan clutch. I picked up a fan clutch from Napa today. FYI Napa Part number #273377. This is a thermal fan clutch. The CUCVs use a non-thermal fan clutch.
Can some provide some input will this make a difference?

Thanks,

stationjj

 

[dependable]

CUCVs have a thermal clutch also, as do all 6.2s in chevy trucks I have seen.

 

[stationjj]

Update I got the fan clutch installed. It did seem to quieten down a bit. If that's possible on a CUCV? HAHA! The old fan clutch was going out so it needed to be replaced.

Got the truck ready for a camping trip to LBL. I thought my issues were fixed. About half way to Land Between the Lakes I started having power lose issues. My girlfriend was coming later after work. I had her bring up a spare fuel filter from the house. I got it installed, and it helped some. It was starving for fuel. The trip home was rough. I averaged about 45 - 50 MPHs. When I hit a hill the truck barely made it. For safety reasons I drove backs road back home and avoided the interstates.

Got home did some research. I was considering dropping fuel tank, and replace fuel sock. I decided to try one last thing and replace electric fuel pump. I think that fixed my fuel starving issues. it idles much better. Idling seems a bit off. I guess the electric fuel pump was dying? The pump was over 3 years old.

I suspect I will have to drop fuel tank. I plan to purchases the parts needed now.

Thanks everyone for your advice and help.