auto_editor

Boy, I never thought I'd look back fondly on the days when her exhaust smelled like a gasoline pump and she had a scary "thump, thump" low-end noise, but it would appear as though something has gone TREMENDOUSLY wrong in the guts of my 307.

Here's what (I think) I know:

It's not oil-related as it comes out bright white and isn't, well, "oily", and the oil level isn't dropping;

It's also not coolant-related because the smoke smells acrid and bitter, and the oil is inkwell-black;

I'm only getting the faintest hint of unburnt fuel now, so far as I can tell amidst the smoke's other overpowering odors;

The smoke comes out of the tailpipe, the valve cover filter and its fittings, the air cleaner and somewhere behind/below the passenger's side "strut tower";

The smoke gets worse the longer the engine runs, irrespective of actual travel (the smoky pics were taken after five minutes of idling);

If you want to escape from the police, just get on the throttle a bit until around 45 mph then jump off the gas. The resultant plume of dense, white smoke that you get in place of proper engine braking is quite a sight;

There's now a "chuff, chuff" sound coming from the engine, and she's down on power. Feels like a "miss", but not like my '79 T-Bird did with a holed piston;

and, the "Check Engine Soon" light goes on and off seemingly randomly.

Semi-Educated Guess: Ring failure. She's blowing pure combustion gasses into her innards and, when mixed with oil vapor and whatever the hell else is in there, those gasses re-enter the carb via the PCV system and *POOF*, instant smokescreen.

SO, since rebuilding the engine is cost-prohibitive, is there something I can try to at least mitigate the issue? I don't mind the smoke personally, and they say the 307 is practically un-bustable, so I'm torn between ignoring the issue until the car stops moving under its own power or is actively on fire, and selling her to someone who can fix/replace her engine and use the cash to buy something else.

A "running" car is always worth more, but to someone not as intimately knowledgeable about her issues, the five-alarm-fire-like smoke cloud she produces narrows the gap considerably.

[UPDATE: Just went for a drive in the 90+ degree heat and noticed a constant high-pitched reciprocating whine, like a water pump going bad, but it's not the water pump. It, and the radiator and hoses and all that are new. Besides, the sound is coming from the guts of the engine, not the outside.]

Thoughts?...

JpMotorsports

more it runs and drives the more damage youll cause what ever it is. it may still seize it self up on you. Id have it checked out and repaired/rebuilt or replaced. you got a issue and it should be fixed or parked. the cops wont like you too much and youll def get pulled over for defective or faulty equippment

tru-blue 442

Is the trans full of oil?
Sucking fluid through
the modulator into the
intake maybe?

oldcutlass

Does it still have a catalytic convertor on it? Does your coolant or transmission fluid level drop?

11971four4two

have you tried pulling and cap of vacuum line to power brake booster???
brake fluid pulled into the engine this route makes helluva smoke

best o luck

steverw

im guessing modulator valve in tranny, cheap easy to fix. Pull the vacume line off the modulator valve and plug it. See if the smoke stops, it may take a few minutes for all the trans oil to burn out of the motor.

nsnarsk65cutlass

The 200r4 doesn't have a vacumn modulator.

Tedd Thompson

If your oil smells of gasoline you may have a blown diaphragm in the fuel pump and it is thinning the oil down and letting it pass through the rings. This could be a potentially dangerous situation if it thins the oil to the point it will combust......Tedd

oldolds88

and check the cat,if it still has one. if its not bad,it will be from the contaminants.

BIGJERR

Broke a ring if I was a guessing and I am.......

johnnyjaws

Blown Head Gasket

rustyroger

It used to be a common thing over here to see cars doing what you describe after someone had put diesel in the tank by mistake.
My mother managed to do it twice on two visits to a gas station, then I told her I would fill it with gas for her from then on....
There are plenty of other valid reasons why your engine is doing what it does, all posts before mine are possibilities.


Roger.

natedrag

Smoke smells acrid and bitter? Sounds like COOLANT, only thing that burns with that terrible bitter stink. Head gasket or cracked head I would guess.

Octania

I have a bone stock 307 if you want to gamble on a basic swap. Or I can find a 350 maybe. central lower MI area

MDchanic

My money's on the head gasket. Hold your hand right up by the exhaust while it's really smoking for a minute, then lick your palm - if it tastes sweet, it's coolant, and it's almost definitely a head gasket.
All of the details you mention would fit with a blown head gasket.

Of course, a compression test and a cooling system pressure test would help to clinch this one.

Also, as stated above, it's not hard to pull the vacuum lines to the modulator and the booster and see if either one is full of oil.

- Eric

auto_editor

Winner, winner chicken dinner. I figure. It never occurred to me that when she puked her coolant out the overflow tank and i had to replace the radiator (it was like 75% sediment) five months ago that the gasket could go too.

Its likely, right?

Now I have to unpaint myself out of a corner: I cant afford the rebuilt & replacement route, but you have to basically disassemble the engine to fix it, so rebuilding it with old parts makes no sense. I'm stuck.

Feel free to swoop in with the (relatively) easy answer and help me write the rest of this story.

Otherwise it might come down to selling her. So, I guess, I welcome offers of all kinds. But the sooner the better. I dont have the driveway space to just keep her around waiting while I drive something else this winter...

tru-blue 442

You may see if Chris can hook you up
with a good used 307 or 350.
Good luck with the decision.

oldcutlass

You can either do a valve job and replace the head gasket or just replace the head gasket.

nsnarsk65cutlass

Agreed,except todays coolant has bitters in it ,so pets don't drink it.

MDchanic

I guess not all of it does, because I did this just a few months ago. Maybe it's certain regions or brands.
Though if it tasted bitter, I guess that would be your giveaway, too.

- Eric

MDchanic

Thank you. Extra Crispy will be fine.


I'd say so. Overheating did the damage, but it took a little while for it to finally go.


The problem is that your engine is so completely covered with tubes and wires that doing the relatively easy head gasket replacement is a royal PIA.

All you actually need is a new intake gasket (about $30) and a single new head gasket (about $20). I MAY be mistaken, but I believe that these cars even used thicker fiber head gaskets, instead of the thin shim gaskets, so the parts store Fel-Pros wouldn't affect performance.
If you've got the patience, you can hack through the jungle to get to the intake and head, pull them off, and replace the gaskets, then put it all back together (take LOTS of pictures of all the plumbing).
Just be sure to put your MAW helmet on good and tight.

Of course, if you can locate someone selling a used, running 350 not too far away for a reasonable price ($300 or less), now would be the time.

- Eric

ent72olds

Too bad, looks like a nice car. I had an '84 delta that ended up doing that. Turned out that the intake gasket let go around one of the water ports on the head.

auto_editor

Through the magical process of doing absolutely nothing the "whiteness" of the smoke is gone, the coolant level stays steady (though a tiny bit seems to be seeping out onto the driveway now, but I can't tell wherefrom for sure) and the "chuff chuff" sound got louder but it (and the engine bay smoke) has been traced to the join(s) between the exhaust manifold and whatever's between it and the cat.

So I guess the plan is to replace the exhaust gasketry and bracketry or whatever and be left with a car that still smokes a bit but only from the END of the exhaust system.

Or not. Every turn of the key these days is an adventure...

MDchanic

Sounds great! I love when they fix themselves.

Now you've got time to keep your eye open for your next motor, so that you've got time to find the best deal.

- Eric