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Hi everyone. I've been posting about my car on another forum but someone suggested coming here because it is F-body specific.
I'll try not to ramble, but I want to provide context and important details.
This car has suffered from sitting for a long time, and from my own stupidity. I ran straight water in the engine before parking it outside (it lost its parking spot to my GTO that winter) and of course two core plugs popped out. After that, it sat on my lawn for a pretty long while before I got it back into a garage space t work on it. Heater core was massively burst apart, so I replaced that along with the two core plugs.
I am having a cooling issue that I cannot diagnose. Coolant will come out of the overflow reservoir cap if the engine runs along enough. Also, if I run the engine for a while and crack the two bleeders, I get a rush of steam, not water.
I do not see any signs of coolant in my oil. I also hooked up a cooling system pressure gauge to the radiator cap and started the engine. I wanted to see of the pressure rose rapidly, indicating combustion pressure in the cooling system. After six minutes, the pressure gauge was only at 7psi. I did not continue the test after that point because I assume combustion pressure would reveal itself in the system pretty immediately.
A fellow who said he works on these cars advised me to make sure I am following the correct bleeding procedure to get all the air out. This is what he advised:
"1. Fill the radiator completely.
2. Insert a large funnel in the radiator that will seal to the neck, filling the funnel a few inches above the top of the rad. This funnel is the key to getting the radiator level above the engine to force air out the bleeders.
3. Crack bleed screws to let air out.... once you get water out, close them.
4. Start car & allow to run a few minutes. Re-bleed the system, keeping the level in the funnel a few inches above the top of radiator. You may also have to lift the funnel, slightly to let the air burp out of the radiator..... yes you will make a mess.
5. Lifting the front end also helps.
6. Don't ever open the bleed screws without pressure in the system or with cap off, you will let air back in.
Get the cap back on before the engine gets too hot, & let it build pressure. Then you can burp the bleeders again. If you start to boil it over, you will let "Air" out that is steam & mess up the whole process."
Today's , I got my CPAuto spillproof funnel kit from Amazon. Eagerly awaited for the baby's nap so I could try it out.
I followed the above bleeding procedure step-by-step with no deviation. I got water out of each bleeder pretty quickly today, before starting the engine. Started engine for a few minutes, kept water level in my funnel nice and high, cracked bleeders again. Got water with some air bubbles, closed bleeders again. Got a burp of air inside the funnel. I also pulled the funnel out of the radiator for a second, as Lonnie suggested. Water level in funnel was rising and turning brownish.
As engine heated up, I removed the funnel and adapter and got the cap back on the radiator. Cracked bleeders again and sure as heck, from what I can tell, they were now shooting steam. So, I shut the engine off.
Tell me if this means anything: I used the infrared thermometer on my two radiator hoses. From what I understand, the hose on the driver's side, which enters the radiator higher up, is the "upper" hose and is where the hot coolant enters the radiator. Hose on passenger's side, which leaves radiator down low, is the lower hose returning "cooled" coolant back to engine.
My thermometer showed the lower hose, where it enters the thermostat, to be around 180-200 degrees (I checked it a bunch of times after turning the engine off).
The upper hose seems strange to me. Near where it exits the thermostat, the temp was higher (180 or higher) but then right where the hose enters the radiator, the temps were lower than 120 degrees. I checked many times along the length of the hose to see if I was maybe just mistaken about what the readings were.
Isn't that odd? It's making me wonder if that hose has something inside of it blocking off flow into the radiator. Why else would one end of the hose be 60 degrees hotter? That's a big temp variation in something that is maybe 18" long.
Anyway, that is where we are at for today. Thanks for sticking around. I'm grateful for the help. The car deserves better treatment than I have given it, but I'm hoping to change that. Life got in the way for a bunch of years and it just sat.
A common cause of overflowing the coolant reservoir is having the connections at the radiator for the radiator overflow tube and the return from the throttle body (which is actually a continuation of the steam pipe from the back of the heads) reversed.
Did you use the pressure test device to pressure the system to 18 PSI (radiator cap rating) to see if the system held the pressure, and didn’t bleed down, indicating a system leak?
Thank you for replying. The fellow on Garagejournal who directed me here referenced your name, specifically. Were you ever on the old PY Pontiac board?
I will review the procedure and links you linked me to above. I feel like my reservoir lines are correct, but I will triple-check that.
I did use the pressure tester on the system as you described a few days ago. The pressure did drop slowly, and two small leaks appeared underneath the car (one very tine and the other somewhat larger). I could not see where they were coming from, but figure they did account for my drop in pressure. I performed this test to see if there might be a head gasket issue or cracked block, before performing the test where I ran the engine with the gauge hooked up and no pressure on the system to see if combustion gases were pressurizing the system.
Tonight, I decided to have another shot at this. I watched some videos for how to use the no-spill funnels and it seemed so simple. Insert proper adapter to get a seal, fill funnel 1/3 of the way, run engine and wait for all bubbles and burping to be over.
My experience was pretty different.
There was plenty of bubbling and flowing when the car heated up. There was so much, in fact, that the funnel started spilling over onto my alternator. When I shut the engine off, the funnel emptied pretty quickly and sucked air into the system. That was my mistake to allow that to happen. So, I repeated this process but made sure to have water ready to pour into the funnel so it did not become empty after turning the engine off. The last couple of times that I did this, the funnel quickly filled up and nearly overflowed, but when I shut the engine down it does not empty out, the level just gets lower. I am getting steady water out of the bleeders with the engine off and the funnel full.
It sort of feels like the coolant is not flowing properly, but I am just a hobbyist hack and don't really know whether that is the case. It seems like it all wants to surge up into the funnel rather than circulate through the radiator and the rest of the system. It's just definitely not the like Youtube videos where people use these funnels to burp their systems and they get some gentle bubbling action for ten or fifteen minutes and it's done.
The overflowing coolant that I managed to catch in a container is very brown and there are chunks/flakes in it. If nothing else, the system is very dirty. I see at least one short evergreen needle in the container, but I can't be sure if that was already in there when I grabbed it as the funnel was overflowing.
I started with an extension on the funnel which I didn't really need but thought would be good to raise the level of water even higher, to assist with the bleeding process. Is it normal for this much water to be coming out of my exhaust? I'm assuming it's from sitting for years without being driven.
Are the videos you've been watching specifically for an F-Body LT1? The Corvette LT1 cooling system is different, and includes a self-bleeding pressurized reservoir. Too bad GM cheaped out on the F-Body.
Water is a byproduct of burning gasoline. Some condensation in the exhaust is normal, but mostly in cold weather. A few drips at startup in hot weather is normal. If you are starting the engine repeatedly for short periods without letting the exhaust system heat up, water will continue to build up. With the nose of the car in the air, it’s eventually going to run out the exhaust tips. If it was burning coolant due to a head gasket leak, the smoke might be on the white side and have a “sweet” smell. Your spark plug in the leaking cylinder would be exceptionally clean.
System looks sludged up, possibly creating hot spots that could boil the coolant when the cap is off, and no pressure in the system.
@shoebox is the expert in the area of the cooling system.
PY is the old Performance Years website that was hosted by Ames Performance, the Pontiac restoration parts company that also created the Pypes exhaust system line. I think it used to be the largest classical Pontiac website around in the olden days.
The videos I have been watching were not F-body specific, just people explaining how to use one of these funnels to bleed a system. I assumed the functionality of the funnel would be consistent across platforms.
The system is definitely dirty as all get-out. I think I am going to try pulling the knock sensor, radiator, drain plug to flush it out as well as possible.
I cannot verify that the t-stat is operating properly, but it is literally brand new so I did not think it could be part of the issue. I ordered the t-stat at the local parts store by telling them the car that it is for, so unless their computer misdirected them it should be correct for the engine.
The LT1 cooling system is unique. It is commonly called “reverse flow”, and therein lies the problem with bleeding the air from the system. Conventional engine cooling systems feed the cold coolant to the bottom of the block, surrounding the cylinders. The coolant rises to the heads and then returns to the radiator. The LT1 system sends the cold coolant directly to the heads, then it flows downward.
There's an extensive, detailed paper on the design of the LT1, presented to the Society of Automotive Engineers by a GM engineer, stressing the benefits of reverse flow cooling, and (ooops) the Optispark ignition. Reverse flow cooling is a proven benefit in engine design. The owner of Evans Waterless Coolant has a patent on the design, and was working semi-informally with GM on the update of the SBC design. Evans sued GM for violation of his patent in the LT1 design, but initially GM prevailed. I believe eventually Evans gained a partial victory, but by then GM had learned how to use the principle in later engine designs, without calling it “reverse flow”.
Follow the Shoebox procedure. The reverse flow design is also the reason for the LT1 specific t'stat design. You can’t use a t'stat for a Gen 1 small block Chevy. Also the reason for the “steam tube” venting air and water vapor from the back of the heads into a vapor/liquid separator in the radiator.
I was a long-time Pontiac fan, having owned (all purchased new):
- 1966 GTO Tri-Power 4-speed
- 1968 Firebird 350 4-speed
- 1973 Grand Prix 455 HO
- 1980 Bonneville station wagon (what happens when you have 3 kids)
You used the past tense; is your Pontiac fandom a thing of the past?
Once I get the system back together after it is flushed, I will absolutely follow the Shoebox procedure to a tee. I plan to use straight water at first so that, if there is anything wrong even after the flush, I won't have wasted new coolant and created a disposal chore for myself.
I have always been a Pontiac guy. All my cars were bought used and none cost more than $5k. That's just all I've been able to afford over the years.
I have this Formula left, and my '69 GTO which I bought from my brother back in 1994.
Other Pontiacs I have owned include:
1967 Lemans 326 convertible
1969 Catalina convertible w/400
1976 Trans Am w/400
1977 Grand Prix w/455 from a '76 GP
1978 Grand Lemans
1992 Trans Am 350 TPI
1992 Formula 350 TPI and t-tops (one of just a few hundred made; I regret selling it)
1995 Formula A4 that I converted to M6. I traded it for the '76 Trans Am listed above
I'd love to have a vintage Pontiac wagon of some sort, for my three kids. Maybe a '76 clamshell Bonneville/Catalina.
I eagerly removed the knock sensor on the passenger side. It came out very easily with a wobble extension, deep 7/8 socket, and 1/2 drive ratchet. I think it was removed before, as there is gobs of some kind of sealant where it mates to the block. The part that the wire harness connects into is wobbly. I'm going to replace it to be safe.
I ran lots and lots of water from a hose through the empty thermostat hole. I was able to attache a brass fitting that I had to the block, with a rubber hose on it, to more easily collect the old fluid. I wanted to see what it looks like as I progressed and I want to be able to dispose of it properly. As you can see from the images, the first bucket is very, very dirty. The rectangular gray bucket is what result I had before I turned the hose off to have lunch. I'm going to do it again once I am able to do the driver's side.
Since the car is at a steep angle, am I trapping sediment at the back of the block, or is the flow of the water carrying it out through the drain hole?
The plug on the driver's side is very difficult to access. I think I am going to have to drop the y-pipe, which I'm not looking forward to. I think someone did this before, because the images I have seen online show a raised plug in this location. What I have is one of those plugs that installs almost flush, with a recessed hex drive in it.
If I'm going to flush the system, I might as well be thorough, especially given what the coolant looks like that came out of the passenger side. How can that mud not be part of the problem that I am having? I mean, I guess we will find out.
I want to strain this stuff through something to see how much sediment is left behind. Might make for an interesting picture.
When you buy a new knock sensor - good idea - make sure it is the one for 93-95. They changed it to a sensor with a significantly higher resistance in 96/97, and they are not interchangeable.
I can’t remember what the driver side block drain plug looks like. I haven’t crawled under the car for many years. May even be sold by the end of the month.
I think I have a thick parts manual for the '93 F-bodies that I can pull the number for if it is the same for '93-'95. '93 was the last year for the paper parts books, IIRC.
Is your car on NJ Craigslist? Are you stepping away from the hobby and forum?
As far as my car, I bought it brand new in 1994. I heavily modified it up through 2005. I took a new job that year, and it totally eliminated my spare time for the car. It’s been sitting unused for many years. Now that I'm retired I just don’t have the physical abilities to do the maintenance and upkeep. And even if I did, I don’t think it's a good idea for someone my age to be making 9-second, ~140 MPH passes at a drag strip. I live near the Old Bridge Township Raceway Park (for 47 years the site of the NHRA Summer Nationals), and went there a lot. They closed the strip down two years ago. Too many complaints from people who built their McMansions 40+ years after the track was built. They make more money renting the site to Copart to store thousands of salvage late model cars.
A friend of mine knows a car collector and has been telling him about my car for years. He's looked at the car, we've been going back and forth, supposed to be here this week to close the deal. This guy is an attorney, big $$$$ and has a 64 car collection. My car is immaculate, best of the best performance parts, high quality work by a licensed mechanical engineer (me) and a high quality engine shop in Pennsylvania.
As a fall back, I have a potential buyer in Colorado, but the logistics are an issue to me.
I'll be sad to see it go, but happy it’s going to a good home.
It felt like a good day in terms of progress. Having some time to wrench on a car again makes me feel like a more capable hack.
It's clear that a previous owner put some aftermarket parts on this car without putting many miles on them afterward.
The bolts for the y-pipe were very surprising in that they came off quite easily.
Shouldn't there be a clamp where the y-pipe enters the catalytic converter? Mine has no clamp and there is wiggle in the joint.
Once the y-pipe was off, I was able to get much better access to the block drain plug on the driver's side. Using a hex bit and ratchet, I could feel and see the bit start to turn without the plug moving; the hex head was going to strip and I knew that would create a high level of suckness. I knew an impact was my best hope. I tried my Cornwell 3/8 impact for a while but the plug would not budge. Used a 1/2-3/8 adapter to get my Earthquake involved and the plug came out immediately.
The coolant that drained out of the hole is pretty dirty, but not as dirty as what I removed yesterday. I hope to have time to flush this side thoroughly tomorrow.
My headers are rusty and I am afraid they will develop holes. Since I need to replace the plug wires and might as well also do the plugs, I think I should pull the headers. I have a friend who will glass-bead blast them for the cost of a case of Miller Lite. Then I think I will use like an Eastwood or POR15 high temp coating on them to get some more years out of them.
Somebody changed the cat. It’s not the correct one. When it left the factory, the cat was welded to the Y-pipe. It has been cut off, and replaced with a 2-bed+AIR converter used on pre-1993 models. The pipe sticking into the side of the converter connects to the secondary air (AIR) pump on the pre-93 models. The older models ran air into the manifolds on startup, then diverted the air flow to the cat to oxidize unburned HC and CO. The 93 and up system does not work like that. The AIR pump runs for 3-4 minutes at cold startup, then shuts off. The cat does not need the extra air injected in front of the second bed.
I don’t think POR 15 will stand up to headers temperatures. And it isn’t recommended to apply it to a sand-blasted bright metal surface, as I recall. Check with manufacturer. Looks like the headers were either painted with high temp paint or possibly cera-metallic coated. The cera-metallic coating should have held up better. Might have been a poor quality job. A new cera-metallic coating is best - reduces under hood temps, keeps heat in the tubing, increasing velocity and scavenging - worth a few extra HP. But they may be too far gone for that.
Is there any need to change this cat even if it' not the correct type? The AIR pipe on it looks to be capped and the AIR system on the car has actually bee removed. I was just thinking of adding a clamp where the is none to prevent leaks.
I know that regular POR15 won't handle high temps, but I believe they offer a high temp coating for headers and manifolds. If not, then I know Eastwood does. Having them professionally coated probably isn't in the budget, which is very modest for this project.
