KDMatt

Long story short, I told my better half to take my '82 T/A to work yesterday so that I could use her SUV to potentially launch the boat (and let's refrain from the sexist remarks if we can, please.) I got a call some time later that there was "smoke" pouring out from under the hood. I got there and saw that coolant had sprayed everywhere and the car had gotten so hot that it effectively sputtered to a halt.

Got it pushed to a lot to let it cool down for a few hours, then I manage to limp it back home. The culprit of the whole affair seems to be a bad radiator cap -- the reservoir cap overflowed with coolant, presumably draining the radiator and letting the system run dry. (I've only seen it happen once before, and that was on an old Lexus.)

Now, as you might imagine, it's running like garbage. The upside though, is that the coolant is looking free of any tell-tale "milkshake" symptoms, and the oil still looks clean. There's also no abnormal smoke coming out of the exhaust either. As far as I can tell it's misfiring now and running super rich.

Oh, and the details are -- stock 305 V8 w/ Crossfire EFI. Only codes its throwing at me are for the coolant temp sensor (which is to be expected after an overheating incident) and the MAP sensor (which is to be expected from an engine struggling to maintain idle.)

I did a video walk around of me starting the car today (a full day later) -- in the video I'm progressively giving it more and more throttle until it finally fires.. then slowly letting go to see if it'll hold idle, and eventually it does, but just barely:
https://drive.google.com/file/d/0BxV...ew?usp=sharing

Also grabbed a video of the reservoir overflowing, which is what's leading me to think I've got a bad cap:
https://drive.google.com/file/d/0BxV...ew?usp=sharing

I'm gonna pull a couple of sparkplugs to see if maybe they got fouled in this debacle... any other ideas on things I could check that would have gotten screwed up by overheating so badly? I'm hoping the motor's not a total write-off, but even if it is... no time like the present for a 350 swap?

Thanks in advance,

- Matt

OrangeBird

iTrader: (1)

You have a blown head gasket (Or a really BIG crack in a head or the block) that's leaking one of your cylinder's compression into the cooling system . that's why the overflow tank is bubbling like that and why it's misfiring . A compression test would tell you which cylinder the bad head gasket is near , but in practical reality if doing one head gasket , might as well make it a twofer .....

mk1431

possible warped head

ex-x-fire

Look for coolant in the oil.
Do a coolant pressure test to find any leaks.
Your rad cap is probably fine, it was relieving pressure. You could have a stuck t stat. Remove it & test it in a pot of hot water.

igotta355z28

iTrader: (1)

You do not always have coolant/oil intermix with a damaged head gasket/head. Go buy a cheap block tester and Ill bet good money you will find compression gasses in the coolant.... You can also do a compression test, find what cylinder/cylinders are low and then use the compression gauge hose to pump compressed air into those cylinders while they are on the compression stroke with the valves closed and I bet you'll see bubbles in your radiator... There are lots of quick ways to figure it out... Heat kills engines...

KDMatt

Thanks for the replies everyone.

I'll start by grabbing a block tester to see if I find gases in the coolant. I'm betting you guys are right and I probably will.

At this point I'm starting to see two options...

1 - pull the heads, replace gaskets, replace heads (or get them machined down) + hope the lower end (i.e. piston rings, etc.) survived the heat well enough.

2 - pull the motor and replace the whole thing

What would you do?

dmccain

iTrader: (2)

A good time to find a 350 to replace it with. Even 350 Goodwrench would be a nice upgrade and you could throw that CFI setup right over on it with no problems I don't imagine. I think I saw these engines for $1459 Free Shipping from either Jegs or Summit recently.

KDMatt

I was kind of thinking of going that route, tbh.

Like, grabbing the good wrench 350 along with '82-'84 corvette manifold/injectors for the CFI on the 350 (unless they were totally identical on the 305) -- just to keep it bolt-on for now, with possible upgrade options down the road.

EDIT: I might also want to look at different transmissions -- if I'm going to to the trouble of yanking the powertrain out, it could be a good time to find something with an extra gear.

greenyone

iTrader: (1)

reman 305 heads are pretty cheap and a lot of places will even take the cracked ones as cores....if you decide to go that route.