Driving home last night, white smoke from exhaust and hood - blown HG?

Bosch

Registered User
I'll try to be as thorough as I can, thanks for help in advance. Car is 35th anny manual, mostly stock except larger air intake and the 10% overcharge pulley from the previous owner, 215k miles on the clock - original owner did an engine rebuild at around 200k although obviously I can't verify what all was done or how complete, just kinda trusting that things were done/done right.

Headed home from work outside of Denver late last night around 10 pm, 15 degree clear weather. I'll be completely forthright - I knew I should have let it warm up first but I did a couple pulls because the cold air at this altitude lets the supercharger run better and I wanted to have some fun after work. Anyway, I'm on the highway cruising at around 65-70 when the heat starts giving out and I'm like "oh great did the heater core go" but then I start seeing white smoke billowing out the rearview. I turned off the heat, and then the same smoke starts billowing out the vents, notably the defroster vents. I get closer to home and hit a red light and I see there's white smoke coming out from under the hood. I'm almost home when the CEL finally kicks on. I get it parked in my carport and shut it off immediately. Open the hood, smoke everywhere, when it clears out it's pretty apparent that coolant's been blowing everywhere. The coolant reservoir was dry so I poured some extra in just to feel like I was doing something - at the very least I don't think it would hurt to add some.

edit: one more thing, obviously once I noticed there was an issue I didn't push the car very hard but I want to say that I did not notice a loss in power, or a rough idle when stopped.

I let it sit overnight because it was ~~~~ing cold and I wasn't sure what to do and I didn't want to burn my hand on anything while the car was hot. I'm about to check the oil for milkiness and crank it over to see if there's an obvious coolant spray coming from somewhere. Please let me know what else I should check myself before I bite the bullet and take it to a shop. If it is the head gasket, I'd like to at least try and replace it myself, and if that ends up being the case, can anyone point me to a detailed guide? I've been searching all last night and this morning and generally all I can find are people essentially asking 'what do i do,' but I'm not seeing any guides posted anywhere.

edit 2: A HA. I believe I have found my culprit, which, on the face of it, should be a lot easier than a HG repair. I'll leave this linked to see if anyone can identify which hose it is while I pore over my manual - I'd really appreciate it if someone could give me a rundown on how to access it easily.

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I'll try to be as thorough as I can, thanks for help in advance. Car is 35th anny manual, mostly stock except larger air intake and the 10% overcharge pulley from the previous owner, 215k miles on the clock - original owner did an engine rebuild at around 200k although obviously I can't verify what all was done or how complete, just kinda trusting that things were done/done right.

Anyway, I'm on the highway cruising at around 65-70 when the heat starts giving out and I'm like "oh great did the heater core go" but then I start seeing white smoke billowing out the rearview. I turned off the heat, and then the same smoke starts billowing out the vents, notably the defroster vents. I get closer to home and hit a red light and I see there's white smoke coming out from under the hood. I'm almost home when the CEL finally kicks on. I get it parked in my carport and shut it off immediately. Open the hood, smoke everywhere, when it clears out it's pretty apparent that coolant's been blowing everywhere. The coolant reservoir was dry so I poured some extra in just to feel like I was doing something - at the very least I don't think it would hurt to add some.

If it is the head gasket, I'd like to at least try and replace it myself, and if that ends up being the case, can anyone point me to a detailed guide? I've been searching all last night and this morning and generally all I can find are people essentially asking 'what do i do,' but I'm not seeing any guides posted anywhere.

I’m not a Supercoupe expert, but I’ve blown HGs before in 2 of my SCs. White smoke billowing out the rearview sounds a lot like a blown headgasket. The fact the coolant reservoir was dry is pretty concerning. Could have been leaking for a while either because the gaskets were blown or the leaking (for some other reason) brought the fluid level so low that air bubbles were trapped and maybe they became hot spots and thats how it blew. Check your radiator and see if its full or low. When you lost heat, that could have been because coolant was dangerously low.

It also sounds like you ran the car for a bit after you had warning signs; your heads and block surface might be warped, especially if the car overheated.

I’m just a Youtube mechanic, but the headgaskets have blown in 2 of my Supercoupes; the giveaway in one was milky oil, the other had white smoke out the exhaust. With the help of my mechanic friend, replacing the headgaskets was not too bad. You dont have to have milky oil to tell if HGs blew, but it is one indicator. The other is to run the car till hot and check for bubbles escaping through radiator or coolant reservoir. But I wouldnt do this test if I were you because running the car more at this point might not be a good idea.

Note: when refilling coolant, always remove that bleeder bolt on top of the engine; 13 Mil wrench/ratchet. Burp the radiator hoses really good.

Edit, oh, I see your second edit now. Still should check radiator and see how low it is.
 
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If tailpipes smell like coolant then it most likely a blown head gasket. When head gasket fails exhaust gasses enter the cooling ports and push out the coolant thru the 16 psi radiator cap and into the expansion/overflow tank. When that tank fills up it starts dumping coolant under the hood. Motor will quickly overheat without coolant in motor or radiator. If it was head gasket you should also have felt a misfire on at least one cylinder.

An old radiator hose blowing could do the same thing but it wouldn't have coolant actually inside your exhaust pipes, just clouds of smoke in back of car that came from coolant spraying onto the motor, then overheating because there was no coolant in motor.

If you can't tell if coolant is in the exhaust, pull all the spark plugs and see if any has coolant on them. Next step is compression test.

David
 
@Rick - the temperature needle never got above halfway, I think I avoided an overheat catastrophe. It was definitely low, so was the reservoir. I added a bottle I had on hand before cranking it over just now. It ran fine, no smell from the pipes, I let it sit for a bit and pulled the throttle and saw smoke billowing from that crack which is how I found it. And yes, the first thing I had to do when I got this car was replace the t-stat gasket so I was aware of the bleeder bolt :D

@Dave - I am thinking that it's the coolant that was spraying into the motor, like you said. I didn't feel any misfire, and nothing blew through the radiator cap or into the overflow tank.
 
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@Rick - the temperature needle never got above halfway, I think I avoided an overheat catastrophe. It was definitely low, so was the reservoir. I added a bottle I had on hand before cranking it over just now. It ran fine, no smell from the pipes, I let it sit for a bit and pulled the throttle and saw smoke billowing from that crack which is how I found it. And yes, the first thing I had to do when I got this car was replace the t-stat gasket so I was aware of the bleeder bolt :D

@Dave - I am thinking that it's the coolant that was spraying into the motor, like you said. I didn't feel any misfire, and nothing blew through the radiator cap or into the overflow tank.

Ok, that’s good to hear. I almost blew a gasket (in my brain) around Thanksgiving when I found out that the radiator was over a gallon low on coolant in my parent’s GMC Suburban but everyone in my family kept driving it with an empty overflow reservoir and never bothered to check it. I hope I saved that truck before anything happened to it (the truck does have a slow coolant leak somewhere, maybe a hose). So I’m extra OCD about coolant levels now.
 
Good morning

The pictured hose goes to the heater core. If the hose is factory (swedged) the clamp ends will need to carefully cut off for replacement. Take the hose to your local auto parts store for a match. I suggest replacing the upper and lower radiator hoses. And as suggested remove the radiator and have it professional checked. Replace radiator cap. In my location Winters can be forgiving for cooling operation, Summers are not.


From my experience there is the "blue or red" pill approach.


BLUE PILL.

Ensure a good radiator.

Check accessory serpentine belt, tensioner and pulley.

Check the fan for operation. Does it turn on between O and M based on the instrument cluster.

Check the overflow tank hose for blockage. With engine running check for evidence of heavy trail of bubbles.

Check for additional leaks (ie Timing Chain Cover, Thermostat Housing, Water Pump, Oil Cooler).

Check for evidence and smell of antifreeze out of the exhaust.


No problems noted. Return to service.

RED PILL.

In addition to the BLUE PILL list add the following.

Scan for codes. I purchased an OTC I & II 3211. Check for live data. ECT vs instrument cluster reading. Check the fuel short trim reading. Check oxygen sensors readings.

Check the 2 Air Condenser to Radiator foam weather foam sealing blocks. Replace if damaged or missing.

Check the air filter. Clean the Mass Air Flow sensor.

Perform a fuel pump pressure test.

Change the fuel filter.

Check the air dam. If it Damaged and or Missing you need to replace it. No longer available from Ford. A trip to the salvage yard GM section for Saturn or Pontiac SunFire yields a good match.

Check the harmonic balancer. If original (factory) and or Dorman replace as soon as possible with a Power Bond or BHJ. Don't forget to replace the washer and bolt.

Correct any problems. Return to service.
 
I believe I have found my culprit
I replaced that hose on my Anny less than a year back. Not sure I recall all details, so... As already noted, that's one of the upper heater hoses. I think there is a PDF with an drawing that shows the coolant layout/flow/hoses on here somewhere. It's taken from the factory manual I think.

Remove the DIS, air intake tube & oil filler cap (plug the hole with a clean rag, or tape it over) so you have room to work. Try -not- to spin the standoff that holds the hose & ECT sensor...you'll break the seal and risk a small leak there later. If you spin it, consider taking it all the way off so you can re-seal it where it sits. Make sure you put it back in the same orientation...see your photo.

Remove both clamps by whatever means, then, if the hose is welded to the pipe & fitting, carefully slice it open so you can peal it away.

Use emery cloth to clean the rust off the pipe & fitting (I repainted the pipe end), then size it for replacement - I don't recall if I bothered with a molded elbow. When installing new clamps, try to clock them so you can still get at them later with everything put back together in order to re-tighten as needed.

If the pipe is wasted/rusted/bent, source a replacement, and of course expect more work - the more careful you are up front, the less risk of making things worse.

Search here on best practice for bleeding air out of the system when done. Can be tricky get rid of air pockets, like right under the ECT sensor.

If you get it back together, and you wonder about headgaskets (if not obvious at that point), AutoZone rents an exhaust gas/combustion tester you can use on the expansion tank. Check it for sludge, etc.

obviously once I noticed there was an issue I didn't push the car very hard

You might have lucked out and it's just that hose, but I'd recommend not driving it further/at all, once you see steam/trauma

That hose isn't alone - be sure to examine all the others, including behind the engine and over the driver side valve cover, also the smaller hoses at the water pump. Might be time to grab a new 16# radiator cap if yours is years old.

Good luck.
 
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I just want to repeat and emphasize - CHECK ALL THE RUBBER HOSES.

If this one cracked, the others may not be very far behind if any.

RwP
 
I


You might have lucked out and it's just that hose, but I'd recommend not driving it further/at all, once you see steam/trauma


Good luck.

Don't worry, I'm not driving it anywhere until I at least get that hose replaced and check the others.

Thanks everyone for your help, I'll come back if I have any more questions. Not sure when I'll be able to dig into this, my wife's more or less out of work due to covid and my daily driver(an old diesel pickup) seems to have just shat its alternator.
 
I've probably owned 35 or so SC's and probably replaced headgaskets a similar amount of times. Personally I've blown that same hose and also had similar fears of headgaskets. From what you described I wouldn't fear the head gaskets. Ive done much worse in terms of overheating and been okay on a stock motor. The fact the motor was recently rebuilt also gives me confidence you're fine.

If it were me I'd used a razor blade, slice that hose off, head to your local parts store have them supply you with a pice of bulk hose and 2 hose clamps.

In terms of replacing the coolant. Remove the 13mm bolt from thermostat housing. Fill the radiator till its full. Put on the cap. Squeeze the upper hose till coolant hits the top of the threads where you removed the 13mm bolt. While hold the hose to keep the coolant top thread the bolt in and tighten down. Crack the radiator cap, top off. Fill the overflow bottle and start things up.

-Tim
 
Okay, got the hose replaced, replaced coolant/burped system. No other leaks spotted - rented the exhaust gas test kit and it passed. If I had the knowhow and money I would do some more of the tests recommended, but I'm gonna have to call it good from here. My other hoses look okay relative to how the busted hose looked. Drove it around til it was warm and the evil CEL stayed off, which makes me feel better. Thanks all for the help.
 
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