Loud squalling noise from Inline 6

[rusty66]

I am having trouble with my 250ci inline 6 stock engine. It won't idle. Carb looked dirty, black gunky inside so I have decided to rebuild the carb. The truck is also now making an awful sound like a cat squalling. Anyone that could help me figure out the likely cause, I would appreciate the help. The truck still has the generator setup.

[AZKen]

Can't help you until you tell is where the noise is coming from and when it does it. Is it the motor or the chassis or steering or what? While idling, while driving?.... You say the truck is making noise, that's a big area. Could be fan belt? We can't hear it from our house. Gotta help us a little.

[TJ's GMC]

I am having trouble with my 250ci inline 6 stock engine. It won't idle. Carb looked dirty, black gunky inside so I have decided to rebuild the carb. The truck is also now making an awful sound like a cat squalling. Anyone that could help me figure out the likely cause, I would appreciate the help. The truck still has the generator setup.

When does it squeal?

[FetchMeAPepsi]

Black gunk in the carb probably means the same stuff is in the fuel filter too. And the tank. As for the squeal, it's probably the tail lamp that needs greasing. It happens alot. :teehee:

[AZKen]

I'm guessing radio between stations. I have seen FMAP's cause many times also.

[rusty66]

Glad I could give you guys a good laugh. Pretty sure its not the radio since the truck does not have one. I will change the fuel filter when I rebuild the carb. I haven't been able to keep the engine running to get close to the noise as I have no help and the truck won't idle. I think it might be a bearing in the generator maybe.

[TJ's GMC]

I wouldn't be surprised if it's the water pump. They can make some noise. lol

[rusty66]

When a water pump goes out do they usually leak? I haven't seen any indication of leaks so far.

[rusty66]

The fan belt looks ok, no cracks or bad spots and it is tight.

[TJ's GMC]

When a water pump goes out do they usually leak? I haven't seen any indication of leaks so far.

Buddy of mine had one go out and never mentioned it leaking. My 46 case tractor's pump leaks but doesn't squall. lol The seal is shot.

[AZKen]

Sorry about the idle problem. Gotta get that fixed also. Take off the belt(s) and start it up and see if it squeaks. That will tell you if it's the belt or something it drives. You can't tell if a belt squeaks by looking at it or tightness.

[FetchMeAPepsi]

Glad I could give you guys a good laugh. Pretty sure its not the radio since the truck does not have one. I will change the fuel filter when I rebuild the carb. I haven't been able to keep the engine running to get close to the noise as I have no help and the truck won't idle. I think it might be a bearing in the generator maybe.

You start it, it starts, then dies? Is that right? All within a few seconds? (10-20)

If so, maybe your generator is out and it's not able to keep the truck running. I hear they're easy to rebuild, but you could also swap to a GM 2 wire alternator too pretty easily. You might can kill 2 birds with one hammer!

[rusty66]

Thank you all for the advice. I will let you know how it comes out soon.

[GMCDAC]

Hi Rusty66, I will add one more thing, that may or may not apply to your generator. The one on my '55 GMC has lubrication ports on each end. I know this generator is later model than the truck but I don't know how much. Once a year I add a couple drops of 10wt oil to them.

DAC

[turbobill]

I am having trouble with my 250ci inline 6 stock engine. It won't idle. Carb looked dirty, black gunky inside so I have decided to rebuild the carb. The truck is also now making an awful sound like a cat squalling. Anyone that could help me figure out the likely cause, I would appreciate the help. The truck still has the generator setup.

Sounds like a vacuum leak. I've seen carburetor base and body gaskets act like a reed in a musical instrument, resulting in some pretty strange noises. Make sure everything is tight. Also spraying carb cleaner or some other solvent around suspected area's may help you find vacuum leaks too.

[rusty66]

Hi All,
Changed the fuel filter and have a carb kit from NAPA. Got some help from my wife and started the truck after changing the filter. It still won't idle but the noise is from the base of the carb I think, as Turbobill suggested. i will work on the carb kit tomorrow. Looks like I might have to replace the gas tank and fuel lines at some point too.

[AZKen]

Good work Rusty and Turbo!!!!!
Rusty, I think that filter tells you something. Make sure you clean everything well. Your fuel system is "Gumby ******"

[bluestreak1854]

Check to see whether something is stuck in the PCV valve. If it's dumping too much vacuum, it will make the engine run rough and not want to idle and can sometimes make a squealing noise.

[bluestreak1854]

Also the squalling noise could be from a stopped up exhaust system.

[rusty66]

Very late update. I took the intake/exhaust manifold off and cleaned up the surfaces and replaced the gasket with one from NAPA. Put on the carb I got from GMCDAC (thanks again Doug). The engine runs and idles now. Thanks to all for the help.

Gary in Tenn.

[GMCDAC]

Very late update. I took the intake/exhaust manifold off and cleaned up the surfaces and replaced the gasket with one from NAPA. Put on the carb I got from GMCDAC (thanks again Doug). The engine runs and idles now. Thanks to all for the help.

Gary in Tenn.

That's great to know Gary! I'm glad you are getting the old truck running well again. Get some pics for us sometime!

DAC

[Pops]

you've probably done this, but it's worth looking for vacuum leaks. all rubber lines esp one going to pvc at back of valve cover. if leaking big enough that can squal. if you have power steering, there is a check valve at booster that can malfunction. also did you use all gaskets and seal down the rebuilt carb? sure you did. I believe there is clearance on carb at linkage. too much wear at that point may produce noise. Lastly, for now, does your heat riser still work? Is there a leak in that area? Get your rubber hose out (home made stethoscope) and check. Hope you can keep it running after you get you filters changed (stone filter in carb esp.)

[Pops]

sorry for the previous post. I didn't see page two which covered most of my points. Did you get rusty running?