cooling system issue question

[BarryK]

well, tried to take the '78 to DMV today to get her registered and tagged but stopped for gas on the way and ended up having to turn around and come home........

The cooling system - radiator and expansion tank are both gurgleing and percolating.
I had filled it so that the coolant was at the "COLD" mark on the expansion tank when I dropped the motor in earlier this week.
looking at it now it's hot, smoking, and boiling but still now below the "COLD" mark on the tank.

You think it was just air trapped in there that needed burping to allow more coolant into the system and by adding more I should be OK or does it sound like something more serious.
Before I got the gas station and noticed the problem I had only driven about 7 miles or so
The temp gauge never went over about 210* so I don't think it's really overheating too bad but the coolant is definitly bubbling like crazy

 

[Bob Chadwick]

I would let it cool and add a 50/50 mix to the tank and the radiator. Sounds like you have air in the system that is working it's way out. Is is set up properly to suck the coolant into the radiator? Mine draws from the top and requires a hose to go from the cap down into the bottle. When I first got it the hose was missing and it would blow the coolant out but couldn't draw it back in.

The fact that it is not getting hot is a good sign.

 

[Vettehead Mikey]

Sounds pretty typical to me. It's not easy getting the radiator 100% full the first go round, some guys overfill the overflow reservoir to compensate.

The engine will suck in the required amount of coolant as soon as it starts to to cool.

Nothing to sweat about.

 

[BarryK]

thanks guys

I let it cool down a bit so I could remove the radiator cap and it took about another 1/2 gallon of 50/50 mix. I than turned it on with the cap still off and let it run to come up to temperature so the t-stat would open up.
I'm not sure if the t-stat was still open from my running it before but once it reached temp it didn't suck down anymore coolant for me to add to it but it must have been flowing because the upper rad hose was getting hot all along it's length.
The temp didn't go over 200 this time.

Still not sure it's at 100% though so i'll check it the same way again tomorrow. I WISH I had swapped in a new t-stat when I had everything apart. I meant to but forgot and when it was time to button everything up I just grabbed the old one that had been in there and put it back in. I don't even know what temp rating that t-stat is - 160, 180, 195??
I guess I got a bit impatient during my reassembly and I HOPE it doesn't end up biting me in my a** now.

 

[LT4man]

Barry,

I think doing it this way is actually better for you. Now you can see where the temp of the engine is. Based on that info, you can decide if you want to even mess with the thermostat. Maybe you will be satisfied right where it is.

On these older cars, one needs to warm up the engine and then shut it down to cool several times. As you have seen, now you have the right amount of coolant in the engine. You have also found that you can run an engine with the radiator cap removed and you will harm nothing. When your upper radiator hose is hot all the way from the thermostat housing to the radiator, you have reached critical mass!

Save The Wave!

 

[BarryK]

lt4
good point. even when things don't go exactly right it does become a learning experience. since i'm so new at all this stuff pretty much EVERYTING is a learning experience.

UNFORTUNATELY, tomorrow will be another new learning experience as I get the fun job of learning how to drill out a broken valve cover bolts out of the cylinder head. I was double checking all the bolts since I've been running the motor and the valve cover bolts were very loose and as I was tightening up one of them it sheared off on me. :eek

 

[brusso]

Bummer about the valve cover bolt. There are numerous methods to remove them. It all depends on what is left of the bolt. If it sheared flush with the valve cover then you may be able to get away with using vise grips to turn it out. If it sheared flush with the head just have patience with the drilling.

As far as checking the radiator goes. take off the cap when engine is stone cold. Like before you start it up at all that day. If all of the air is out and the coolant is up to par in the overflow tank. You should get some spillage out of the radiator cap. The coolant should be right up to the top of radiator. On older cars without overflow tanks, the coolant would be an inch or two below the radiator cap. This was to allow for expansion. The purpose of the overflow hose, on the older cars, was to vent air in and out.

 

[geekinavette]

well, tried to take the '78 to DMV today to get her registered and tagged but stopped for gas on the way and ended up having to turn around and come home........

The cooling system - radiator and expansion tank are both gurgleing and percolating.
I had filled it so that the coolant was at the "COLD" mark on the expansion tank when I dropped the motor in earlier this week.
looking at it now it's hot, smoking, and boiling but still now below the "COLD" mark on the tank.

You think it was just air trapped in there that needed burping to allow more coolant into the system and by adding more I should be OK or does it sound like something more serious.
Before I got the gas station and noticed the problem I had only driven about 7 miles or so
The temp gauge never went over about 210* so I don't think it's really overheating too bad but the coolant is definitly bubbling like crazy

Barry...I don't mean to be negative here...but I disagree that this sounds "normal". You should NOT have any "gurguling" at 210 deg...air in the system or not. I hate to even think this....but that's about what temperature a small crack in a cylinder head will start to open up and allow combustion pressure into the cooling system (don't ask me how I know this!). The coolant itself will not be under enough pressure to open up the radiator cap and cause the "gurguling"...that pressure has to be coming from somewhere. Of course it's possible the cap itself is bad and just not holding the pressure it's supposed to...or the temp gauge is off and it's really 250 and not 210.

This is all based on my own experience (and a tiny amount of applied physics LOL)...so I may be...no I HOPE seriously that I'm wrong...but I gotta tell ya, gurguling at 210 would give me the heebee-geebees. (AGAIN!)

Bill

 

[elints]

If you have the original radiator for the L-82 then it is a 4 row. At this point in time they tend to develop failure spots on the intake end in the top rows. I have seen this type of happening occur only after the engine starts to heat.
If your overflow tank stays full after the engine cooled and the radiator level is down there is a good chance you may have a crack or two or more as mentioned.
If this is the case don't hesitate to put in a good aluminum radiator. The repair the original radiator only means another failure in the near future. Most original replacements (half the price of the aluminum) won't perform as well as the aluminum.

Good luck. Stable C-3 cooling in warm weather can be a challenge with the original design.

 

[Bob Chadwick]

UNFORTUNATELY, tomorrow will be another new learning experience as I get the fun job of learning how to drill out a broken valve cover bolts out of the cylinder head. I was double checking all the bolts since I've been running the motor and the valve cover bolts were very loose and as I was tightening up one of them it sheared off on me. :eek

If you've got a little of the screw stickeing out, take a hacksaw blade to it and make a slot. You might be able to then get it out with a screwdriver.

 

[BarryK]

Geek & elints, gee, just make me feel good first thing in the morning...... as if I don't have enough to worry about! :eek
Well, like I said, it already took a 1/2/gal of additional coolant yesterday which overall seems like a lot and i'd imagine enough to make a difference in the cooling capacity. i'll check it again today to see if it will take anymore than run it on the street and see if there is an improvement.
BTW, I know the temp sender isn't off and only showing something like 205-210* instead of 250* because I checked it with my IR temp gun.

Brusso & Bob, I agree. I need to pull the valve cover this afternoon and first see where the bolt sheared off. If i'm lucky (I'm not usually lucky though) there will be enough sticking out of the head to grab it with visegrips and just unscrew it out. If I'm not lucky and it's flush with the head than I'll have to drill it out.

Bob, a hacksaw blade??!! you tell me where there is enough room to get a hacksaw inside and positioned correctly in a fully assembled late model C3 engine bay!

 

[Bob Chadwick]

Bob, a hacksaw blade??!! you tell me where there is enough room to get a hacksaw inside and positioned correctly in a fully assembled late model C3 engine bay!

You can dream can't you. otfl

 

[geekinavette]

Geek & elints, gee, just make me feel good first thing in the morning...... as if I don't have enough to worry about! :eek
Well, like I said, it already took a 1/2/gal of additional coolant yesterday which overall seems like a lot and i'd imagine enough to make a difference in the cooling capacity. i'll check it again today to see if it will take anymore than run it on the street and see if there is an improvement.
BTW, I know the temp sender isn't off and only showing something like 205-210* instead of 250* because I checked it with my IR temp gun.

heheheh...didn't mean to cause a panic bro'....but just be aware that IS a possibility (it happened to me). I DO hope beyond all hope that I AM WRONG!

Brusso & Bob, I agree. I need to pull the valve cover this afternoon and first see where the bolt sheared off. If i'm lucky (I'm not usually lucky though) there will be enough sticking out of the head to grab it with visegrips and just unscrew it out. If I'm not lucky and it's flush with the head than I'll have to drill it out.

Bob, a hacksaw blade??!! you tell me where there is enough room to get a hacksaw inside and positioned correctly in a fully assembled late model C3 engine bay!

A dremel with a cutting wheel maybe? Might also soak it for a while with a good penetrating oil. I seem to recall some stuff called PB Blaster that worked very well.

Bill

 

[BarryK]

Geek, I hope you are wrong also for my sake. The LAST thing I want to do now that I've spent the last 6 weeks pulling, cleaning, refinishing and repainting the motor and all of it's parts and pieces, reinstalling the motor, rehooking everything up, etc is to have to take everything apart once again to pull a head off of it!
Honestly, it may be a bubba comment, but if I have a crack in the head I'll go out and get some JB Weld and try to fix the crack before I resort to a complete teardown again.

 

[BarryK]

well, just got done working on the car to fix those issues from yesterday.....

the valve cover bolt:
Man, I got REAL lucky here. turns out once I removed the valve cover that I didn't shear off the bolt afterall. I KNEW I hadn't had it anywhere tight enough to do that! The problem was that the valve cover gasket I used was thicker than normal I guess and it wasn't allowing the bolt to go down enough to catch a good enough grip on the threads in the head. It must have been hanging on by 1 or maybe 2 threads only and when I went to tighten it it slightly stripped out the top thread and that's why i felt a "snap" and it started freespining, it just wasn't catching any threads.
We ran a tap to repair the threads in the head, put on a different gasket that wasn't as thick and everything is great on that now.
That was a big relief!

cooling system:
after the car sat all night and it was nice and cold, the coolant lever should have been at the "COLD" mark on the expansion tank but it was WAY below that level so we filled up more coolant to bring it to the cold mark which took yet another almost 3/4 of a gallons. We let the motor run quite a while and she never went over approc 190* on the gauge and after shutting her down there was no more percoluating of the coolant like yesterday.
My buddy Tripp who was helping me out said the percoluting yesterday was just from air trapped in the system trying to get out and it was also keeping the coolant in the exp. tank from getting into the system and therefore it was percolating because of the air coming up thru the tank.

I noticed a lot of knocking yesterday during the drive down the road and back so knew we had to redo the timing and when we checked it it was way off so we brought it back to a good setting and I'm sure that is helping the car run at the lower operating temp we observed today - between the extra 3/4 of a gallon of coolant and the adjusted timing it's now running 15* or so cooler than it was yesterday.

 

[Tritium007]

Barry, it might have been mentioned earlier, but I didn't see it. You might want to cycle the heater controls with the engine running to get any air out of those lines as well. Say a prayer for the heater core first.

Mike

 

[brusso]

Barry, it might have been mentioned earlier, but I didn't see it. You might want to cycle the heater controls with the engine running to get any air out of those lines as well. Say a prayer for the heater core first.

Mike

Good point. Also, glad to hear that everything has turned out relatively well.

 

[srs244]

barry
i realize i just arrived a bit late at the party, but in the future, a way to avoid the air in the system (assuming that is in fact the problem) is to start your coolant fill through the thermostat housing with the radiator cap off. the housing off and the thermostat removed. it will aid complete fill of the block and will fill the radiator from the bottom up to a great extent (until the coolant reaches the level of the housing), not the otherway around. hope you solved all your problems and they turn out to be minor in scope.


steve

 

[BarryK]

Steve

yep, I agree and that's how I filled the coolant in my '65 but on this '78 by the time I was ready to put the coolant in I have everything else pretty much hooked up and I'm sure you know what i mean when I say with all those hoses and vacuum lines getting back thru all that to undo the T-Stat housing wasn't the most pleasant thought to consider.........

i DID get through it finally but now today I had to start the process all over again
I discovered a bit of a leak in the lower trans cooler line on the radiator and the only way to reach the clamp on the hose was to drain the coolant and undo the lower radiator hose, fix the issue, than start dealing with coolant fill agaon and it's giving me the same headache but at least I know how to deal with it now.
it's always something.............