Best methods to rule out blown head gasket following loss of serpentine belt

[69GTX]

2 weeks back the PS pulley & drive belt came off my 1999 Camaro SS (346 ci V8 - 20K miles). The car had only been on the road for 5 minutes when it occurred. I was only 1/2 mile from my Auto Repair Shop so I headed there knowing they'd be doing the work. In hindsight, the PS pulley came loose and was digging a groove into the PS reservoir, which leaked some oil on to the alternator. When the pulley finally came off with a "bang" it took the belt with it. I pulled into the shop with coolant temps just reaching the "260-265 F" red line area. The temp gauge on these is a "dummy" gauge that reads low band, normal band, and overheated. So it's really a question mark as to what temps the car reached. The shop told me they checked for codes and cleared them all during the repair.

Besides the new PS pump/reservoir and belt, it got fresh Mobil 1 0W-40 oil and Mobil 1 oil filter. The shop said they saw nothing in the coolant system or motor oil to suggest anything abnormal. They didn't perform a coolant pressure check as I requested. And they could have easily done a combustion gas check on the coolant system as well....they didn't. Since I've had the car back I've vented the cooling system a number of times and checked for any "combustion" bubbling at the filler neck. A sample of the fresh motor oil taken from the oil pan at 20 miles appeared clear and with normal odor....no signs of water. No puffs of white smoke on startup or during rpm bursts. No misfires or performance degrades. Normal coolant temps. No signs of dripping coolant under the engine or anywhere else. No oil coolers serviced by the coolant system.....the PS cooler was removed years ago as it's a problem point on these cars.

The only "symptom" I'm still not sure of is that I'm apparently losing or shifting 2-3 tablespoons of coolant out of the radiator filler neck after each run. After 4 venting runs all the air pockets "should" be gone. Prior to this incident, coolant level always stayed right up into the filler neck. Now it ends up about 1/4" to 3/8" below the neck, into the main tank. That's only several tablespoons of fluid. Oddly, I hear a gurgling or water moving just as I vent the cold cap each time. I wonder if that is moving fluid into the overflow and giving me that slightly less than topped off/lower coolant level I am seeing? The overflow tank shows level at the "cold" fill line when cold, and at the "hot" fill line when hot. So anything abnormal there. If those multiple tablespoons are going there, it's too small to accurately measure.

I guess I still need to do a coolant system pressure check and possibly a combustion gas check. Can't rule out that even if the head gasket is not leaking that the aluminum heads could have been warped. Any other thoughts? Thanks.

Photos of the PS reservoir gouging, worn plastic grooves/splines on the pulley center, and missing chunks on the pulley after it banged around. I've heard of a couple other pulleys failing in this manner, but it's certainly not normal on a 20,000 mile car that saw only hobby driving, no track days or drag strips.

 

[2strokeNorthstar]

Doesn't sound promising at the end. Pushing coolant into the overflow and gurgling sounds could be a headgasket. You could also be lucky and just got a bunch of air in it. Gauges on newer cars are awful, on 90s BMWs by the time it was showing hot it was too late and damage was usually done. You need more testing to be certain.

 

[slacktide_bitog]

Any coolant mixing with the oil? Any coolant oozing out of the overflow bottle?

Possibly you can bleed the coolant. The Lisle coolant funnel is awesome.

Another possibility is the heater core. Does it smell like coolant inside the car? Is it wet on the passenger side floor under the glove box or near the center of the car on the passenger side footwell?

Yeah you only have 20k on the car, but it's still 25 years old and full of plastic that's cheap even by GM standards

If it is the head gasket, you can try head gasket sealer and/or add some coolant leak dye

 

[69GTX]

Doesn't sound promising at the end. Pushing coolant into the overflow and gurgling sounds could be a headgasket. You could also be lucky and just got a bunch of air in it. Gauges on newer cars are awful, on 90s BMWs by the time it was showing hot it was too late and damage was usually done. You need more testing to be certain.

With the cap still on, there should be some sort of pressure/vacuum in the coolant system until the cap vents. I don't know what the gurgling is or if flow is occurring as it only happens when the car is fully cooled down and cap first cracked. Doesn't happen again until the next heating/cooling cycle. It's possible something with the cap or tube to the overflow could have been "cycled" during the overheating, and now not functioning 100%.

 

[69GTX]

Any coolant mixing with the oil? Any coolant oozing out of the overflow bottle?

Possibly you can bleed the coolant. The Lisle coolant funnel is awesome.

Another possibility is the heater core. Does it smell like coolant inside the car? Is it wet on the passenger side floor under the glove box or near the center of the car on the passenger side footwell?

Yeah you only have 20k on the car, but it's still 25 years old and full of plastic that's cheap even by GM standards

If it is the head gasket, you can try head gasket sealer and/or add some coolant leak dye

I don't see any signs of coolant in the oil or oil in the coolant. Overflow bottle level is always between "cold fill" and "hot fill" as is normal. Coolant dipstick shows nothing oily on it. No smell of coolant in the car and carpeting on the passenger side is dry. Today I had the car up on ramps and vented the coolant system best I could with t-stat open (190+ F) and heater running. The coolant wasn't touched when it was in the shop so any "new" air in there would have had to come from boiling coolant, which occurs right 260 F with the DexCool at 50/50.

 

[edyvw]

Any mixing? Any mayonnaise on the oil cap? Any increase in oil level?

 

[69GTX]

Any mixing? Any mayonnaise on the oil cap? Any increase in oil level?

No signs of any mixing that I can see.

 

[Skippy722]

My Durango hit 350F (the gauges read identically to the live data) for an undetermined amount of time, and being the stupid 20 year old I was I drove it home with the logic of “wind cools things!”

It worked, until it didn’t, turns out the water pump was bad... though the engine/headgaskets themselves never gave me a problem for the 4 following years and 55k miles, and I was never “nice” to that car.

 

[PontiacHO]

After belt-pulley issues are fixed, get the engine up to operating temperature, shut it down. Slowly remove radiator cap and use a cooling system pressure checker to pump up 16 lbs on the system. Pull all the spark plugs and observe conditition of plugs (wet) as well as watching for steam from spark plug hole. With plugs out and the 16 lbs of pressure still on the cooling system, spin the engine over like trying to start it. If any coolant and-or steam is blown out of spark plugs hole(s) then you’ve found the blown head gasket or cracked head. You will need someone to sit in the car and attempt to start as you watch the spark plug holes. Also pull PCV valve and look for milky pudding substance.

 

[zrxkawboy]

My best guess is that you're still getting air out of the system. Time will tell, of course.

 

[K-Man]

Earlier this year I had to drain the coolant to replace the thermostat and temperature sensor in my 2011 Ranger (4.0 SOHC), which had been running cold. I reused the coolant (long-life Motorcraft Gold), which had only about 10,000 miles on it, and filled the block up to the thermostat housing before installing the new thermostat and re-sealing the system. The idea was to minimize air in the system. Then I finished filling the radiator and ran the truck for a while to check things and get it up to temperature to check the gauge.

Still, even with that, it took about 2 weeks for the air to finish clearing from the system, based on the level in the reservoir. You might have had the same thing in your Camaro.

 

[BC1]

Maybe I missed it but was any work done disturbing the cooling system when replacing the power steering pump? Why do you keep taking off the radiator cap? It will suck what it needs from the over flow each heat cycle. Just let it be and check the overflow each morning stone cold. After a couple days it will stabilize.

 

[Kira]

it took about 2 weeks for the air to finish clearing from the system

So, do these experiences support using a vacuum filling tool?

 

[69GTX]

Maybe I missed it but was any work done disturbing the cooling system when replacing the power steering pump? Why do you keep taking off the radiator cap? It will suck what it needs from the over flow each heat cycle. Just let it be and check the overflow each morning stone cold. After a couple days it will stabilize.

The cooling system was untouched by the shop. It didn't appear that they even topped off the fluid. And other than the "missing" 1 ounce of coolant after a run, there are no other symptoms yet of any engine "damage."

I check the cap routinely because prior to this incident, the system always kept itself full into the filler neck. It's not doing that now....with level ending up 1/4" or so down into the radiator. So while it could still be air slowly bleeding out.....it's too early to rule out leaking out of the engine in a "micro" amount. Maybe the overheating disrupted the back filling from the reservoir during cool down.

Someone else suggested running the car several times over a week or so and then checking. If it's only down the 1 ounce, then probably just a minor issue with the overflow system operation. If it's down several ounces, and down nearly an inch in the radiator, then it's a leak.

 

[69GTX]

After belt-pulley issues are fixed, get the engine up to operating temperature, shut it down. Slowly remove radiator cap and use a cooling system pressure checker to pump up 16 lbs on the system. Pull all the spark plugs and observe conditition of plugs (wet) as well as watching for steam from spark plug hole. With plugs out and the 16 lbs of pressure still on the cooling system, spin the engine over like trying to start it. If any coolant and-or steam is blown out of spark plugs hole(s) then you’ve found the blown head gasket or cracked head. You will need someone to sit in the car and attempt to start as you watch the spark plug holes. Also pull PCV valve and look for milky pudding substance.

Excellent advice. I need to get a coolant system pressure checker. But, I'm not ready to have a shop tear into the engine until everything points to that as the problem. Pulling plugs on this 350 V8 is a nightmare....at least for me....esp the rear 2 on each side under the cowl. The PCV valve looks dry and clean.

 

[Nukeman7]

Excellent advice. I need to get a coolant system pressure checker. But, I'm not ready to have a shop tear into the engine until everything points to that as the problem. Pulling plugs on this 350 V8 is a nightmare....at least for me.

In regards to getting a coolant system pressure tester, see my #12 Post in this recent BITOG thread.

 

[BC1]

Romp on it 20 minutes or so each day to get it hot. Check the dipstick and overflow each morning. It is probably fine. The misfiring should show up on a cold start if it is leaking into the cylinders.

 

[JohnnyG]

Does it have the air bleed line that comes off the highest point of the engine, like the Northstar did?
On the Northstar, there was a hollow bolt at the top of the throttle body that would get plugged on occasion.

Check to see if that line is flowing to the coolant tank and not burping air. (If it has that small hose)
Should flow coolant any time the engine is running.

 

[69GTX]

Romp on it 20 minutes or so each day to get it hot. Check the dipstick and overflow each morning. It is probably fine. The misfiring should show up on a cold start if it is leaking into the cylinders.

So far this is what I'm doing. 4 runs completed. Will do several runs now before opening the coolant system again. Engine purrs on startup....and no white smoke.

 

[69GTX]

Does it have the air bleed line that comes off the highest point of the engine, like the Northstar did?
On the Northstar, there was a hollow bolt at the top of the throttle body that would get plugged on occasion.

Check to see if that line is flowing to the coolant tank and not burping air. (If it has that small hose)
Should flow coolant any time the engine is running.

The 1998-2002 LS1 Camaro/Firebirds have a simple, non-pressurized over-flow tank. The only connection to the over-flow tank is the line to the radiator filler neck, just under the cap. There is a throttle body connection (1/8" tube into hose) that runs to the top of the radiator just under the filler neck. I have seen that TB entry hole exposed a couple times now. From what I have read "GM ran the upper engine steam line through the TB in order to heat the TB to prevent icing in extremely cold weather but mostly to aid in cold start warm-up. (less cold-start emissions and faster warm-up times." I will make a note to check that line for flow into the radiator next time the level is down 1/2" or so.