Correct way to fill cooling system help?

A consistent bubble stream might be cracked head(s) and/or failing headgasket(s). Might as well throw a new 16# cap at it, on the hope that it helps. If not, that's one less thing you'll need to buy when you do the heads/gaskets.

I'll pick up a new cap and see what happens
 
A consistent bubble stream might be cracked head(s) and/or failing headgasket(s). Might as well throw a new 16# cap at it, on the hope that it helps. If not, that's one less thing you'll need to buy when you do the heads/gaskets.

What can be causing it to run hot
 
What can be causing it to run hot

Exhaust gases in the cooling system.

AutoZone has a test kit you can rent that will check.

Ny '90 SC is parked right now for the same symptoms, and I confirmed gases in the cooling system. Soon as I can budget $400 for fresh heads, it will be back on the road.
 
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Exhaust gases in the cooling system.

AutoZone has a test kit you can rent that will check.

Ny '90 SC is parked right now for the same symptoms, and I confirmed gases in the cooling system. Soon as I can budget $400 for fresh heads, it will be back on the road.

I was really hoping this wouldn't be the case
 
Feel your pain...had the same hope until I got my hands on the test kit and confirmed.
 
Feel your pain...had the same hope until I got my hands on the test kit and confirmed.

So on yours did you have more than a head gasket problem. Since you're waiting to purchase new heads. If you don't mind me asking where are you getting the heads from
 
Exhaust gases in the cooling system.

AutoZone has a test kit you can rent that will check.

Ny '90 SC is parked right now for the same symptoms, and I confirmed gases in the cooling system. Soon as I can budget $400 for fresh heads, it will be back on the road.

Just called all the local parts stores around me here and none of them know what that tool is. They said they don't have anything like that to rent would you happen to know exactly what it's called because these people around here aren't very bright
 
I haven't yanked the heads themselves yet. My choice is to not plan on it just being gaskets (cracked heads* are not uncommon, I believe), and once these heads come off, they'll basically be just cores.

I talked to local shops, and an outfit in Texas, I think. CHI - Cylinder Heads International - https://www.shop.headsonly.com/main.sc - Best to call them when looking for SC-specific heads, they were very helpful. When I called, they only had one ready, so unless that changes by the time I do the work, I expect to ship mine to them first.

CHI makes it as easy as possible, meaning they ship fresh heads to me and I return mine in the same boxes, all freight built into the transaction. Matter of couple days to receive. If they don't have a pair on hand, they send me boxes, I ship mine and they turn them around, no matter what work they need, in approx. one week. One price gets me fresh heads regardless of what it takes to make that happen, 12 month warranty.

Local shops didn't seem interested, wanting to inspect, then quote work, cost for crack fixes, etc., getting to them as they have time, etc. Quotes when I could get them were always slightly more than CHI - I was afraid of cost creep and being committed once they had my heads, which won't happen w/CHI.

* It's my opinion when you have symptoms on the car of overheating after running a while, with a not big bubble stream in the expansion tank that at least one head is cracked. Badly blown gaskets are more like when you see steam out the exhaust and the engine oil and coolant in the expansion tank turn into a milkshake. I don't have coolant in my oil, but like I said, I do have exhaust gases in the coolant, and same thing, it can run at normal temp if not stressed, but it always goes hot and bubbles (not big) if any load put on it or you just let it idle for 20 ~ 30 minutes, even when the fan works properly.

The tool is a test kit. The test fluid is sometimes separate. AZ's tool program works where you buy it, then use it, then return it and they refund. They didn't even charge me for the test fluid I went thru. The kit and fluid if you buy is around $30 ~ $40. Run the engine until you get a bubble stream, add the required amount of fluid to the tester, push the bottom of the tester into the fill hole on the expansion tank so it seals, and pump the bulb on the top. This will draw the air from out of the expansion tank up thru the fluid which will change color if exhaust gases are present. Took me a couple tries to get the hang of it, but not too difficult otherwise.

https://www.autozone.com/loan-a-tools/block-tester/oem-engine-block-tester/391378_0
https://www.autozone.com/test-scan-...st-kit/oem-block-tester-test-fluid/391381_0_0

If you have to buy them, I found both for sale on eBay, same items.
 
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Picked up a block tester from AutoZone. The fluid for the tester is baby blue color. Started the car and did the test. Used the expansion tank to do the test. Right about the same time as the fan kicked on I got a few bubbles in the tank but didn't last long. Kept performing the test and fluid never changed color. Fan will kick on. When the temp on the inside gauge reaches the M. It's hovers around the M the whole time. Car has tan for about 45 min and stayed the same. Oil looks fine and the car doesn't have a miss fire. After all that time the gauge is now hovering just past the M. I purchased a new cap but wanted to do the test 1st

This is all with the a/c off. Just turned the a/c on and temp started to climb to hot and then stated to get bubbles in the expansion tank. Before that there were no bubbles but just a few right when the fan kicked on the 1st
 
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Sounds like good news, then, except you don't know what might be causing the persistent bubble stream. As for hovering around M, it should drop back to N or O as/after the fan runs. You didn't say it did that, so I'll assume it sits on M regardless.

I'd install the new cap (wet both gaskets), then heat cycle it again, at least once. Watch for bubbles, and see what happens to the upper radiator hose during and after. It's hot of course, but see how hard the upper hose is when the car is fully warmed up, engine running, and how long it takes to relax, and if it collapses after sitting over night. Check the coolant level in the expansion tank to see if you're losing any coolant in the process...cold to hot to cold.

Might be there is a small leak in one of the (many) hoses, or the water pump seal/bearing is starting to go, allowing the system to suck air as it goes from warm to cold. This would put air in the system and cause a repeat of the bubble stream next time it heats up. Air in the system can raise hell w/the ECT, too, so...

Still no joy, AZ rents a cooling system pressure test kit. Mine held full pressure for two hours before I called it off, but I still had symptoms.
 
Sounds like good news, then, except you don't know what might be causing the persistent bubble stream. As for hovering around M, it should drop back to N or O as/after the fan runs. You didn't say it did that, so I'll assume it sits on M regardless.



I'd install the new cap (wet both gaskets), then heat cycle it again, at least once. Watch for bubbles, and see what happens to the upper radiator hose during and after. It's hot of course, but see how hard the upper hose is when the car is fully warmed up, engine running, and how long it takes to relax, and if it collapses after sitting over night. Check the coolant level in the expansion tank to see if you're losing any coolant in the process...cold to hot to cold.



Might be there is a small leak in one of the (many) hoses, or the water pump seal/bearing is starting to go, allowing the system to suck air as it goes from warm to cold. This would put air in the system and cause a repeat of the bubble stream next time it heats up. Air in the system can raise hell w/the ECT, too, so... sounds like I have work

Still no joy, AZ rents a cooling system pressure test kit. Mine held full pressure for two hours before I called it off, but I still had

The temp stays around the M never moves from there. Did I do the test correctly by using the expansion tank? I'll do the cap and see where I stand
 
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It was still pretty warm so I didn't remove the cap but I started it up to let it cycle fans kicked on when the temperature got to the m the hose really never got firm on the upper radiator hose
 
fans kicked on when the temperature got to the m

And then? Did it drop...to where?

hose really never got firm

As long as it didn't get rock hard, or stay limp like when cooled down.

Remind me...how many of the hoses are new, now?
 
And then? Did it drop...to where?



As long as it didn't get rock hard, or stay limp like when cooled down.

Remind me...how many of the hoses are new, now?

It stayed around the M the whole time. Just moves alittle to the left when the fan stays on but stays on the M the whole time.

The hose is semi firm when you squeeze it you hear the coolent in it slosh around. I only replaced the bypass hose
 
Ignoring the bubbles, now I'd have to wonder if the radiator is shot/plugged up. Have you looked inside it with the cap off?

Do the hoses feel real mushy when it's cooled down?

Are you sure you installed the thermostat the right direction? Did it have a small bleed hole?

Does the heater put out hot air when the engine is warmed up?
 
Ignoring the bubbles, now I'd have to wonder if the radiator is shot/plugged up. Have you looked inside it with the cap off?

Do the hoses feel real mushy when it's cooled down?

Are you sure you installed the thermostat the right direction? Did it have a small bleed hole?

Does the heater put out hot air when the engine is warmed up?

The radiator looks pretty rusty inside. I installed the new cap and bleed the system. Only had time to run it till the fan kicked on. No bubbles in the expansion tank. I will have to try again tomorrow. The thermostat would only go one way. Now that it's called down the upper hose is soft but you hear some coolent slosh when you squeeze it. I will have to check the heater tomorrow.
 
So not sure what the issue is now. I've replaced the radiator cap and bleed down the system. Started the car and temp ran up to the M then fans kicked on and cooled it down to the O, then the temp ran back up to the M and cooled down to the O again. Took it out for a drive and it was wanting to run past the M again.
 
A radiator that isn't clean can only do so much, and once it heat soaks, it's bound to struggle.

You might want to get your hands on an IR temp gun and start doing spot checks on the entire system to get a better idea of how things are performing in general

Keep in mind that given the car's age, you can be facing multiple issues (besides engine problems), from failing hoses to slipping belts to underperforming radiator and worn water pump.

Everything needs to work properly on any vehicle, but the SC has it's own demands that tend to raise the bar. Small things that might not be obvious can contribute to overheating, such as missing side baffles on the radiator, missing chin spoiler, wrong coolant/water ratio, even a lowered suspension that upsets the airflow in the front, onto then down the back of the engine and out under the sides/rear of the car.

Sounds like the fan is working ok. Still have a bubble stream? Remind me, did you clean and snug up the connector on the temp sender?
 
A radiator that isn't clean can only do so much, and once it heat soaks, it's bound to struggle.



You might want to get your hands on an IR temp gun and start doing spot checks on the entire system to get a better idea of how things are performing in general

Keep in mind that given the car's age, you can be facing multiple issues (besides engine problems), from failing hoses to slipping belts to underperforming radiator and worn water pump.



Everything needs to work properly on any vehicle, but the SC has it's own demands that tend to raise the bar. Small things that might not be obvious can contribute to overheating, such as missing side baffles on the radiator, missing chin spoiler, wrong coolant/water ratio, even a lowered suspension that upsets the airflow in the front, onto then down the back of the engine and out under the sides/rear of the car.

Sounds like the fan is working ok. Still have a bubble stream? Remind me, did you clean and snug up the connector on the temp sender?

Yes fan seems to be fine, it kicks on consistently. There are 0 bubbles in the expansion tank. I think I replaced that temp sender. Ive been keeping a close eye on what I can under hood as belts and hoses. Radiator issue has been in the back of my mind.

I was surprised to see that the temp actually dropped to the O on the gauge that's the 1st time that has happened and it did it 2 times then stopped working correctly once I was driving it
 
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