Happy holidays y'all.

Here's what's up: Last week was bitter cold out, but I needed to take my 87 305 (carb) to work. Toyota was in the shop. Started it up to let it reach operating temperature then smelled coolant after about ten minutes of it fast idling. Popped the hood, saw burning coolant steam coming from the rear passenger side of the engine, but I couldn't see exactly where it was burning off from. Radiator overflow tank was low too - after idling for only ten minutes. Shut her off, and noticed coolant had puddled in the places where I've attached pictures.

Additionally, the engine is now idling fine, but shutting it off, I get CRAZY dieseling and ultimately a backfire through the carb. I'm afraid to do this any more and throw a rod or something. Prior to this, everything was FINE. I was putting 100 miles a week on this thing no problems at all. Now all of a sudden, what's going on?!





Any insight you guys have would be great. It's bitter cold here so I would really rather just take it to my shop than dig in myself, but if driving for even a small distance like this is horribly dangerous, I'll need a tow. Thanks everyone!

 

The source of your leak can be clearly seen in picture #1 , see the antifreeze on the bottom of the heater control valve your holding ? These valves are beyond notorious for leaking and the hoses right at where they meet the valve could be leaking also . Grab a new valve and some appropriate sized hose clamps , trim 1/2" or so off of the ends of the hoses (or replace them too) if the ends of the hoses are deteriorated , fill the radiator back up as it's likely far more empty than the overflow bottle will indicate , and then run it to check for any other leaks .

PS , buy the "Everco" and not the "AC Delco" , since they are both identical in every way except the box they come in and the price (the AC Delco cost almost 2X the price of the Everco). These pictures show an Everco and an AC Delco branded valve , can you tell the difference ? (Hint , there is no difference) ....

 

Question - how come my 86 Firebird has no heater control valve? Is that just a Camaro thing?

GD

 

My 84 Trans Am does not have one either.

 

Must be a Camaro thing. I need to install a couple manual valves so I can redirect coolant around the core. With the state of the flapper door insulating foam having hot coolant in the heater core has as negative impact on the AC efficiency.

Can I just buy the Camaro valve and hoses, then disconnect vacuum to the valve when I don't want the heater core hot?

GD

 

Thanks for the detailed reply. So I'll definitely need to replace that valve, but would that alone be the cause of white smoke coming from the engine and a rough, dieseling shut down? I'm worried that yes, the heater control valve is toast, but so possibly too is my intake manifold gasket or head gasket (which would suck).

My oil isn't milky but I Did notice some reddish.... sediment? I guess, at the bottom of the dipstick when I went to last check it which I'm sure is not good. Maybe I'm being paranoid but I'm just trying to gauge what I should be expecting if I'm taking this into a shop.

thanks again everyone!

 

Intake gaskets usually leak down, not up. Are you sure it's coolant below the throttle shafts and not gasoline? Looks like it could be blowing back from the heater valve.

Dieseling is a function of either too high of an idle speed, incorrect idle timing, bad anti-dieseling solenoid, etc. It's all about the carb for the most part - a coolant leak isn't going to affect it.

Any kind of "sediment" in your oil is VERY BAD. Change it immediately if you suspect contamination.

GD

 

this happened all at once so I'm not sure how they're related problems if at all which is a total mystery to me. It just all happened at once which is weird, I've never seen anything like this.

I know my carb leaks a bit of gas but this was definitely coolant by the number four intake port. I guess that could be explained by the leaking valve, but the valve and the coolant burning off the engine wouldn't be related would they?

 

Sure - the coolant will vaporize off the hot engine. The engine runs hotter than the boiling point of the coolant when it's not under pressure. And it's not "burning" it's steaming - that's water vapor not smoke. Water vaporization occurs at a much lower temperature than combustion.

GD

 

My understanding is that the heater control valves were an '87 up thing. Can't speak for 86 (as I've seen so few) but I've not seen an 85 or earlier FB or Camaro that had one.

 

Yes , yes it could . Say for instance that valve WAS the only thing leaking , and that it had leaked out a whole bunch of coolant . If it had leaked out enough for the engine to be overheating , this overheating could very well be causing the dieseling . If enough coolant has been lost that there is no coolant in contact with the temperature gauge sensor the engine could be overheating even if the gauge isn't representing the overheated condition .

This is why I advise to fix the known leak first , refill the radiator , and run it looking for any further leaks . If they are there , you'll find them and if not , great , you just saved a trip to that dreaded evil "shop" place where all kinds of automotive and financial sodomy have been known to happen on an all too frequent basis ......

 

It is WINTER now. Don't make the mistake of refilling the cooling system right now with just water because you're not done working on it yet.
It only takes 1 night for the temperature to go down below freezing, and you now have a cracked engine block in the morning. Ask me how I know?

 

Alright, got the heater control valve in, so that's all settled, but I haven't turned the engine over yet since I want to make sure it's cleaned up and free of residual coolant so I can diagnose where any potential steam off could be coming from.

I've got another sort of related problem though that I didn't want to make a whole new thread for. If you guys could help, that'd be great:

It looks like at some point the nipple for the overflow tank has broken off my radiator and now there's just a big hole that I can't really affix the hose to. Has anyone ever fixed this without just replacing the radiator outright? Maybe I could tap a fitting and seal it with JB weld? I'm worried the pressure would be a problem for this but I've got no idea. Any suggestions would be great - thanks.

 

It's not impossible that you could rig the rad that way, but I wouldn't recommend it. Most often, the reason some part of it breaks, is because the whole thing is old and decrepit, and the plastic is turning to dust. Or, if it's an all-copper one, it's been heated up and cooled down so many times, that every seam and joint in it, is cracked and ready to fall apart.

Consider it a sign: it's old, used up, and needs a new one. Every molecule in it is all EXACTLY the same age. (within a day or 2) About the last thing you REALLY need right now, is to be driving down the road with your SO or some satisfactory substitute, and the thing just pops and spews all your coolant out on the road. This is considered BAD. A whole new rad is only about $100. Just do it.

You DEFINITELY can't leave the hole there.

 

Nuts. Would the above solutions I mentioned be good for at LEAST a temporary fix?

 

You can try. I've seen such reckless attempts before, but it usually won't last long. Remember this is plastic, it's now old and brittle, and it's going to be running at 220 degrees with 16 psi of pressure.

New radiators are really quite cheap for these cars. I think the one I'm running now was around $80. That's less than the tow bill will be if your repair fails. Consider the consequences of your choices.

I wouldn't. Though I have the means to just buy a new one without it impacting my immediate ability to provide food and housing to my family so take my opinion with that salt

GD

 

Just like batteries, plastics are dying (breaking down) from the day they are made. I'm assuming your radiator has plastic tanks.

 

Define a few words more clearly:

"Good", "temporary", and "fix"

Or if you'd rather, I'll define them for you.

It will "work" just "good" enough to make you think that it's a success, and convince you to drive the car. It will work just "temporarily" enough to allow you to drive to the most inconvenient site possible, at which point it will fail and spew, and you'll lose all your coolant in a matter of seconds, before you can even pull all the way off the road. You will then have to either pay to have it towed, or you'll have to install a new radiator on the spot. I would refer to such self-defeating behavior as a "fix", in the sense of some sort of alternate-ethnic rigging, as opposed to a "repair". Sort of like the old black-humor aviation joke about how much fuel you had just before you ran out: you had just exactly enough to get you to the site of the crash.

You will spend whatever it costs to half-a$$ the thing sort of together, the price of a full fill of coolant, and a tow bill; THEN you'll get to buy a radiator, and ANOTHER full fill of coolant. Now think: how is the half-a$$ thing going to "save" anything?

Replace the radiator.

 

Oh we had a bunch of em ; "What are the two most useless things in aviation ? Runway behind you and fuel on the ground . You can never be carrying too much fuel , , , , unless your on fire ."

PS , I'll agree with everyone else here , it's new radiator time