Ok so I've been having lots of problems with my 305 over the last few months. When I first got my car it ran fairly well, but after a month or two the car would lose rpms really fast and stall, if I hit the gas from a stop. Next I was driving down the highway when my car suddenly overheated and had to be towed (there was also a tiny bit of steam/smoke that came out from the engine when this happened). Now there is a really loud clicking noise coming from the engine, towards the rear near where the carb is, and the car overheats in a matter of minutes now.

Yesterday I took off the valve covers expecting to find a collapsed rocker or something, but everything under there was intact (except for the gasket, if you could call it a gasket).

What could you guys suggest on checking? The thermostat was just replaced, the fan is engine driven and works, so those aren't the causes of the overheating (at least I don't think). Any help would be really appreciated!

Thanks a lot!

 

a little more info on your car would be helpful...

what kind of condition is the radiator in?

 

It's not leaking any fluids, but that's as much as I know... I did a rad fluid test a couple months ago and it was fine, maybe I should do one tomorrow though.

What other information would be useful?

 

year model of car, engine designation (i.e. tbi, carb, or tpi), or anything else that might be helpful

 

Duh...

1983 Trans Am, with an unmodified pontiac 305, 4 barrel rochester carb.

 

automatic tranny?

 

Auto tranny, yes. 700r4 if I'm not mistaken.

 

check the tranny fluid for a burned smell....

visually inspect the radiator core to see if there is a significant amount of buildup in there.

something else that might be a shot in the dark is check for blockage in the cat converter

 

What about the clicking noise, what would you suggest I check for that?

 

hard to say as I can't hear the noise...

 

It's really strange. Sometimes it's not there, sometimes its constant. It always, however, speeds up with the rpms.

 

that screams valvetrain to me

 

Like I said though, I took the valve covers off on both sides and everything was solid.

 

For overheating replace the radiator cap and see if it helps.
The ticking noise could be an exhaust leak or collapsed lifter. Pulling the valve cover and looking around won't tell you if the lifter is collapsed, it may also just be plugged up with crud. You could try putting a quart of 5 minute motor flush (or keorsene) in the oil and run it for 5-10 minutes (DO NOT DRIVE IT), then change the oil and filter. That should break down and flush out any sludge that may have been trapped in the lifters.

 

It's definitely not a broken lifter, I inspected em all. I've never heard of running kerosene through, is it basically the same as putting transmission fluid in your oil?

 

Maybe an exhaust leak at the manifolds or at the donuts. Or it could be a cracked flex plate.

 

First things first...

Was the clicking there BEFORE the car overheated?


Next...

As for the overheating....you need to go through the cooling system, but there are a few things to check first.

Check the initial timing to make sure it's at spec.

Go ahead and do a flush / fill on the cooling system, it's cheap, and worth the piece of mind. Replace the thermostat and radiator cap as well. Make sure the radiator hoses are in good shape and not brittle or cracked.

Look inside the radiator when doing the above, if you see alot of "slime" inside the radiator, you might want to go ahead and take the time to yank it and have it "rodded out" at a radiator shop ( like $30-40 ) or spring for a new alum replacement ( like $110 ) if the fins and general condition is not that good.

Clean out ALL the gunk, dirt and leaves in front of the radiator.

Now, drive the car.

If it still overheats....HOW / WHEN does it overheat?

Does it overheat when idling / or in slow traffic? Does it run any cooler on the highway at a sustained speed? Does it overheat ONLY on the highway?

If overheating on the highway only, check and make sure you have the plastic air deflector underneath your front end. This forces air into the radiator area for cooling.

If it overheats at idle, it might be time for a water pump. A new one is not expensive, and is sometimes worth the work, especially when you don't know the maintenance history of the car.


The "clicking" could be any number of things. Does it click when you're NOT moving and just revving the engine?

It could be a stuck lifter, as this can happen on and off. Go to NAPA, buy a can of Seafoam and follow the instructions. You'll be surprised at the amount of gunk that will come out of your engine.


Let us know your progress.


HTH

 

305 problems?

That's a lot of problems.

Follow the above advice. The lower air deflector problem may not be as prevalent on your '83, since I believe the '83 TA did have some small air openings at the lower edge of the nose. It's still a good item to have.

As for the engine flush, there are many commercially available solutions, but ATF seems to clean in a more controlled manner. Regardless of which method you use, if you flush, plan on frequent oil and filter changes for the next everal months. You don't want large chunks of liberated sludge clogging the oil passages, pickup screen, or pump relief valve.

SeaFoam works, but is a pretty expensive way to buy paint thinner, alcohol, and oil mixture.
https://www.thirdgen.org/techbb2/sho...hreadid=174734

 

The clicking started immediately after the first overheat on the highway, and I replaced the thermostat at that time. I'll try checking the timing and cooling system today. Will update you guys later tonight. Thanks!

 

Not meaning to insult - but what's the oil like - did you check it? Every car I've ever owned at one time or another has gotten low on oil for any number of reasons - and I always can hear a clicking or ticking noise when the oil gets low/needs changed.

 

If you can accelerate slowly (not stomping on the gas) fine, then I had the same problem in my 307 Olds. It has a 750 cfm Rochester carb. The problem was a broken secondary spring in the carb. It put too much gas in at once when the second two barrels opened up. Without enough air to gas mixture, it tripped over itself and stalled. It is a commonly overlooked problem. Check it out.

 

The oil is definitely not low.. my car had been running fairly hot until this incident so I kept it topped right up. As for the condition of the oil, it looked fine (again before the incident), but I suppose that's something I should look into as well.

As for the radiator, I can't even get the cap off, I'll try again tomorrow because it was getting dark.

 

If it got real hot then it could be a exhaust manifold leak.

You can't inspect a lifter by pulling the valve covers off. You have to take the intake off to be able to see them. You might be thinking of the rocker arms.