Took the 442 for a cruise to the drive in. When I got home it puked on the garage floor...first time that has happened since back on the road. I have been pushing it a little harder on each outing . Reservoir may be a band aid on a bigger issue....so I'll work on that. Meantime, I'm going to add a coolant recovery tank. What year did they start using them so I get a proper radiator cap?
I am thinking of getting this one from Advance and fab up a bracket.

 

How high are you filling the radiator?

- Eric

 

About half an inch above the tubes. Not to the top for sure.

 

I think that's still too high.

If you look at the side of the tank below the filler, you will see a line and embossed letters, which say "FILL LEVEL."

- Eric

 

I went home at lunch and looked at my radiator...the fins and tubes are horizontal duh. I see the mark for cold fill, it measures about 4" below the very top where the cap mounts. I had it about 2 inches below the top so that was too much coolant. The level just now (after vomiting last night) was about 9" down. I'll bring it back up and try again. Thanks Eric.

 

Glad to help out.

It is of course possible that this won't completely fix it, but if it doesn't then there is probably another underlying problem, which will need to be diagnosed.

You should also make sure that you are using a "Pressure" radiator cap, and not a "Pressure / Vacuum" cap.
The "Pressure" cap is made for your application, and will release excess pressure, but will not allow air in.
The "Pressure / Vacuum" cap is made for use with an overflow tank, so that the engine will suck coolant back out of the overflow tank as it cools.

- Eric

 

These cars were designed to run without an overflow, and then the epa and the animal activists decided that a coolant overflow tank was necessary. With that said an overflow tank is an inexpensive mod that is beneficial in the long run and makes it easier to check and maintain proper coolant levels.

 

If your question concerns vented vs. non-vented radiator caps, it depends on whether you have a simple overflow tank or a return tank. The non-vented cap simply lets the overheated coolant out, period. You would use this cap with either an overflow tube or a non-return overflow tank. A vented cap allows the coolant to be sucked back into the radiator once it cools and must only be used with a return tank.

When you use a non-vented cap, you must keep the coolant level in the radiator down at the fill line embossed on the tank to provide expansion room. When you use a vented cap and return tank, you should fill the radiator to the top (but don't overfill the return tank when cold).

Note that a simple overflow tank (ie, a "catch can") will have the inlet from the radiator overflow at the top of the tank. There is no guarantee that the tube from the radiator would actually be immersed in liquid if you used a vented cap and the radiator tried to suck the coolant back in. A return tank has the inlet at the bottom (or else has an internal tube from the cap down to the bottom, like the windshield washer tank). This ensures that there will be liquid sucked back into the radiator.

 

The Dorman 603-001 says it is a "Engine Coolant Recovery Tank". I was assuming it was a return tank and not simply a "catch can". As Joe says, I was under the impression I need a "vented" cap allowing coolant to be drawn back into the radiator. Their image shows an inlet at the bottom so I think it allows for transfer of coolant? So I need that vented cap.
Thanks again Eric, Joe and oldcutlass for your help!

I can't wait for the kid at Advance to ask me what year car this is for and if it is front wheel drive when I ask for a vented cap

http://www.dormanproducts.com/itemde...SEName=603-001

 

Correct.

 

'71 was the first year for a coolant recovery tank in a Cutlass, #410008 will fit in a '68 or '69 ....'73 tank style changed considerably.

 

The 73-76 eldorados have a nice factory tank which looks almost olds... Bend the mounting tab and it looks very close to stock.

 

I think your second reason, and I might add keeping people from burning themselves opening up a radiator cap, are more the reasons for the coolant overflow tank, not the epa and aa. But then I have been known to be wrong.

 

I just installed that coolant tank on my 67 Cutlass. I bought it from Summit for $6.97. I already had a radiator cap and just routed my overflow hose to the bottle. Now that I know it is working correctly I'll get an AC radiator cap.

 

I'm reviving this old thread because I want to add a coolant recovery tank on my Starfire. Though the OP asked which radiator CAP to use I didn't see an answer except the above quote. How exactly do I know if a new cap is the Pressure/Vacuum type that I need?

 

Stant specifies a #10230 cap for your car (and for most of the rest of our cars, as well).

For cars with recovery tanks starting in the mid-'70s, they specify a #10231.

The 10230 is a pressure-only cap:




The 10231 is a pressure / vacuum cap:




Notice that the 10231 says "VENTED" on it, while the 10230 does not.

- Eric

 

Perfect! Thanks Eric.

 

Any time...

 

Assembled / stamped in Meheeko, advertised in Russkie or Polski? Where on earth do you source your pics from?

 

It's Russian. Poles use the Roman alphabet.

I source them from my good old friend Mr Google - used the picture that best showed the stamped text.

- Eric

 

Just out of curisity, what is the maximum pressure the coolant can go before the head gasket is likely to blow in case the radiator cap failed?

 

I think the radiator or thermostat gasket or hoses would go first. This thread is 8 years old.

 

Stant 20231 is rated at 16lbs. Cranking cylinder pressure (compression) is 150-210 lbs. When the fuel mixture explodes in the cylinders the cylinder pressure gets much higher. So unless you've welded your radiator cap closed, I don't think you have to worry about coolant overwhelming you head gasket. Even then, I am sure your radiator, heater core or various heater hoses will pop a leak before you get anywhere near that pressure.