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

[JohnnyG]

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.

Even though that "might be" the main purpose of that line, it is also for other things. It also helps eliminate any air from the system. If it becomes plugged, air elimination is hampered.
The real issue at hand is that it may become plugged with chunks of rubber hose internals, or other gunk like Bar's Leak, which was sometimes added at the factory. (in those days).
The important thing to remember is NOT to blow it back into the block IF you find it plugged. That will just keep the problem for another future time.
Remove the hose and check where it comes from, remove any debris, and reinstall.
Think about it, it doesn't have a seperate thermostat or control of any kind. It needs to flow ALL the time.

 

[ls1mike]

You have air in there. It took a long time to get it out of every ls1 I have had. My 98 and 2000 Z28s and my 00 WS6. Trans Am took a couple of weeks after the last flush I did. All of mine, to include the Caprice, lose some coolant. As far as I can tell and it has been discussed for years is the coolant overflow doesn't seal well and you get some evaporation. Check your cap too. I had one fail on the 98.

 

[ls1mike]

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.

I removed it on all of mine. Get rid of it. I didn't think there were any LS1 cars with that still installed.

 

[K-Man]

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

No. The amount of difference in the reservoir was small. Eventually, again after about 2 weeks, the level stopped changing.

When the car has been driven and you have just shut down the engine, you can carefully touch both sides (ends) of the radiator to make sure of where the coolant level inside is. The radiator won't be nearly as hot above that level. No need to remove the cap if the radiator has a hot area to tell you how high the coolant is.

 

[eljefino]

-- I drove my wife's HHR with a bad cooling fan-- it froze from non-use over the winter. Drove it until the car dinged at me in traffic and the gauge was pegged. Immediately ran the heat, drove 25 down the break down lane to the next exit and cooled the car down. It was fine for another few years (and still so when sold) although there was an exceptionally minor oil slick on top of the overflow tank from then on out.

-- A cooling radiator sucks from a nonpressurized overflow tank via siphon. A siphon needs vacuum. A vacuum needs dead space. Repeatedly opening the radiator cap exposes this dead space and resets it. I also recommend leaving the rad cap alone for a weeks' worth of heat cycles. Monitor the level via overflow tank. Use a sharpie mark for a 60' morning cold start, or whatever's repeatable for you. If you found the dead space full before the incident it was either still lukewarm.

-- I agree with 69GTX, the near overheating excursion may have done something to the radiator cap or something in its wheelhouse. The rubber seal flaps back to allow the siphon-return and if the rubber hardened it won't work as well. Go feel the seal on a new cap compared to yours and you'll notice how much harder it's gotten, I bet.

 

[Dinoburner]

After reading all the posts my suggestion to the OP is to just drive this vehicle for a month or so only checking coolant level in reservoir not radiator. Me thinks all is well, fingers crossed.

 

[69GTX]

After reading all the posts my suggestion to the OP is to just drive this vehicle for a month or so only checking coolant level in reservoir not radiator. Me thinks all is well, fingers crossed.

Basically what I am doing. And will be watching coolant overflow level closely. 4-5 drives of approx 10-15 miles each should tell.
And it just might take weeks before the system burps out all the air left.

 

[siriusc1024]

I overheated mine like that once. 99 T/A. Back when I first got it I went into the post office and left it running. Came out and it was smoking and popping. ECT gauge pegged. People who had it before didn't wire the aftermarket fans correctly.

Since sorted that problem, but the head gasket didn't blow.

Yours has the graphite head gaskets. Check the head casting number. Probably 853. You'll have to replace with graphite because the MLS gaskets don't seal on the notch.

If you did blow the head gasket then excellent time for some 706's or 799's.

 

[69GTX]

A total of 4 drives and 60 miles later. Added no coolant and never opened the cap. Checked the overflow bottle during each run. It was at the Hot Full mark right after the drive. 12 hours later it was at the cold FILL line. It did this every time indicating the overflow system was working correctly.

Upon opening the radiator cap today, the coolant level only dropped at most 1/2 tablespoon.....from the filler neck completely full when I sealed the cap.....to just at the bottom of the filler neck today. This is nearly a negligible amount. No gurgle on the radiator cap as I vented it.....suggested the siphon was still in effect. And that little bit of coolant probably went down the overflow tube upon cracking.
Radiator cap is working correctly too. Oil on the dipstick and under the engine oil fill cap still look 100% normal. No signs of any oil in the coolant. Putting my fingers on the various small hoses of the coolant "steam vent" system just at the end of a run indicates those hoses are flowing coolant.

So no appreciable amount of coolant is leaving the system. Inspected the engine area in detail after every run and no coolant seen anywhere including under the car. The hoses remained "rounded." One member suggested I touch the radiator tank after each run to ensure that all levels of the tank were the same external temperature. And after each run the very top of tank and the radiator filler neck felt "hot" and consistent. So it did appear the radiator tank was staying full. I'm thinking that filling the radiator neck as high as possible right before putting the cap on helps ensure the best chance the siphon effect works. I didn't do that in my earlier posts.

I'll probably still do one more check for "bubbles" with the radiator cap off and idling. And a combustion gas check via the radiator wouldn't be a bad idea either. Thanks for all the various tips and ideas from BITOG members.

One thing I didn't appreciate when the shop had the car was that they refilled the PS system with some sort of red ATF despite me telling them what to use as well as having extra bottles right in the car for them to use. Prior to that the car had always use "clear" GM PS fluid which these days is made by AC-Delco, part #10-5073 (GM 19329448). Best I can tell by reading here and on LS1Tech.com is that plenty of people have done this swap w/o adverse effects. My concern would be on the original 26 yr old factory steering gear seals. There's no real need for all the extra chemicals and detergents found in ATF.....needed in a PS system. The ATF is cheaper.

 

[Sumboodie]

260* for 15 mins isn't killing an engine unless it was already about dead.