overheating ?

[VikingBlue]

twice recently coolant has spurted out of my rad through the overflow tube (onto street, I don't have an overflow bottle).

Both times this happened only after I turned my car off. Once after I had been driving without traffic for 20 minutes in 80 degree weather, and once after I'd been idling for 20 minutes in 90 degree heat.

Neither time did the overflow happen while the car was running, but both times did overflow within seconds of turning the car off.

Any idea why that would be ?

[Oldsmaniac]

I would replace the radiator cap and then see what happens. It would be good to have a temp gauge to read engine temp. Also if you fill the radiator to the top the cap will lift after shutting down.

[don71]

I agree, get a new radiator cap. This should take care of it, unless you have another weak link in your cooling system. The new cap will expose that problem if its there.

[rocketraider]

You don't have an overflow jug. How much coolant are you putting in the radiator? Look on the side of it and you'll see "Fill Cold" marks. If you put in more than required to maintain that level, it is going to puke out the overflow once it gets hot and expands- it has nowhere else to go, and the pressure cap is going to relieve pressure to protect the system components.

This is not directed at any one person, but is generic based on what I see on DF's, at cruise nights, and in helping people with old car problems. Lot of y'all need to remember something very simple.

YOU ARE NOT DEALING WITH MODERN CARS. YOU ARE DEALING WITH OLD CARS. THINGS ARE DIFFERENT.

Anyone with an old car needs the factory service books for it. They will tell you almost everything you need to know to keep your old car running happily. At the very least a Chilton or Motor Professional Trades edition that covers your car.

[joe_padavano]

Originally Posted by rocketraider

This is not directed at any one person, but is generic based on what I see on DF's, at cruise nights, and in helping people with old car problems. Lot of y'all need to remember something very simple.

YOU ARE NOT DEALING WITH MODERN CARS. YOU ARE DEALING WITH OLD CARS. THINGS ARE DIFFERENT.

[size=5]

Amen. I am continually amazed at the number of older cars at cruise nights that have a puddle of coolant under them. I've never had a problem like that with a properly maintained stock cooling system.

[VikingBlue]

I've got that canister with hoses to the gas tank and carb to collect vapors (at least that's what I think it's for) which I think is stock (not sure) in my 1971, which takes the space the correct overflow bottle would otherwise sit. No room for that overflow unless I disconnect the canister.

Also, the overflow hose comes off the neck of the rad just below the radiator cap, so how would a faulty cap cause coolant to spurt out through the hose ?

[Allan R]

Viking Blue,
One simple fix: get a radiator overflow bottle. Joe and Don are right; every new car built now comes with overflow protection. Back in the day, Olds did have a problem with "overheating" in conditions similar to what you've described. The 455's were especially susceptible. That's why they started putting overflow reservoirs into the cars made with BBs. I think it's just a smart thing to do under any circumstances, especially if you are driving in heat, or stuck in traffic. Your engine IS going to run hot because of the lack of air flow, or the really hot ambient temp mixing with the already hot underhood condtions.

Read your owners manual (The one I have is for 1972) but I think they're all about the same. For your cooling system (Page 59)

Check the coolant level at oil change intervals UNLESS THERE IS EVIDENCE OF LEAKING OR OVERHEATING. Do not remove radiator cap when solution is hot and under pressure. COOLANT LEVEL SHOULD BE 3 INCHES BELOW THE LEVEL OF THE FILLER NECK WHEN THE ENGINE IS COLD.

(That should be easy enough for anyone to check)

* Add 50/50 glycol/water as necessary DO NOT OVERFILL.

So there you have it, right from GM. BTW, NEVER add pure glycol; it can contribute to even hotter engine temp, and in really cold weather it can "gel". In an emergency you're far better to just add water.
One more thing, depending on the water quality in your area, you might want to mix your glycol with pure store bought water to avoid crudding up the heater cores, thermostat and rad cooling fins. Good luck.

[Allan R]

Viking Blue

The rad hose overflow is actually part of the tank, not the cap.

Here's a really cool (pardon the pun) link that will show you exactly how the pressure release works to "spurt" the coolant out. Put your cursor on the "overheat" and clik it. Enjoy.
http://auto.howstuffworks.com/cooling-system7.htm

[rocketraider]

Your engine IS going to run hot because of the lack of air flow, or the really hot ambient temp mixing with the already hot underhood conditions.

Olds uses shrouds, rubber seals and fixed air dams around the radiator and core support as part of their cooling system design. These components ensure maximum airflow across the radiator core, both under road speed conditions when a ram air effect does the majority of cooling, and in traffic when the fan does most of the airflow chores. If you have a clutch fan (which most Oldsmobiles since the late 50s have had) it has to function correctly too. If it free-wheels all the time instead of engaging (indicated by a distinct roar), you're going to have temperature problems.

That's why a lot of later cars and ALL transverse-engine cars have electric cooling fans mounted to the radiator. They're engineered to start at a certain temperature, and most all I know of also start any time the A/C is turned on.

If you're overheating under normal conditions, check the fan clutch and the radiator seals. The factory engineers took a lot of extreme scenarios into consideration when they designed your Oldsmobile's cooling system, so it really shouldn't have any trouble cooling itself unless something is not working per design.

###

Viking, you shouldn't have any trouble fitting a factory overflow jug to your car, even with the vapor recovery canister in place. The jugs are identical on all 1971-73 Oldsmobiles (except Toronado without anti-lock brakes, and 1973 A and X body cars). If junkyarding, get the tank and all its mounting brackets.

You can get a closed system pressure cap about anywhere, though I am very partial to NOS AC caps. I'll use a Stant in a pinch, but that doesn't mean I like them. Never mind Stant has been making AC-Delco fuel and radiator caps for a while (ever wonder what that "S" in the cap means?), they just don't look as good as an AC cap.

[VikingBlue]

thanks guys...honestly, it didn't appear to me that the cap inner piece extends down as far as the overflow hose outlet(an inch below) the cap)...that's why I didn't understand how the cap was relevant if the overflow happens at a lower point.

That little video explains things....the cap blocks that outlet ? I guess y'all are right.

And I also guess you're right re: overflow bottle above the canister. Doesn't look like there's enough room but I haven't got a bottle to try it yet.

[cutlassinvt]

are all there cars without overflow bottles stock? or did someone remove them for room at some pt, my 70 and the 3 donor cars that made were all 69-71 and they all had the overflow jug in place

[Allan R]

No, not all of them came with an overflow tank. If you've got 3 donor cars with overflow reservoirs, you are ahead of the game my friend. Use one of them. Are they stock, or aftermarket? Clik this link; it's the overflow I've got mounted in my car FOR NOW until I can get the proper one. If this is what you've got, they are common and easy to replace at small $$. Please post a picture of the spares you've got. If they are original and in good shape, I would like to know how much you want for one.

http://classicoldsmobile.com/forums/...t-tank-018.jpg

[cutlassinvt]

nope, that isnt even close to my overflow, ill take a pic of the one in the car and see if i cant dig one of the others up later on.........

[rocketraider]

Overflow jugs showed up in 1970 as part of HD cooling system option, which was required with factory trailer package options and I think (not 100% sure) W30. Emissions calibrated engines ran leaner and hotter was biggest reason they appeared, though they'd been used on over-the-road trucks for years before then.

You can still find aftermarket overflow systems (see Allan's pic). They work, but finding a place to put them can be a problem. I remember putting one on my dad's 68 El Camino (that always had a chronic puking problem no matter where you set the radiator level) and we put the jug in the washer jar bracket since, like most GM washers, it had quit working about a year after he bought it new.

[Allan R]

Originally Posted by cutlassinvt

nope, that isnt even close to my overflow, ill take a pic of the one in the car and see if i cant dig one of the others up later on.........

Does the overflow bottle look like this one? This is the proper one for these cars.

[cutlassinvt]

i guess i need to move my parts car closer to home, but as near i can tell that looks like my jug, but mines all brownish, probaly just old

[Allan R]

I know what you mean. I saw one like that (see pic) and the guy wants an arm and a leg for it. Rather go with a new GM licensed replacement. Probably going to get it at Fusicks or Parts Place.

If your jug looks like crud but you've got all the mounting hardware, I'd suggest you check out Parts Place. They list the reservoir and all the other parts separately in case you don't need a complete kit.

If you want to check them out, this link will take you directly to the 64-72 Cutlass catalogue. It's a PDF (protected document format) file. So if you clik on the edit button on the web browser and drop down to "find on this page" use the keywords "overflow bottle". Here's the link: http://www.thepartsplaceinc.com/cata...ideimages=true Their catalogue is coming along nicely. As they update it they install COLOR pictures of the products.

[cutlassinvt]

ok, heres the million dollar question, do i really need it at all? its a 70 with a slush box and a 350, its never over heated that i know of, and i absolutly hate a crudy engine bay
i can deal with rust and primer and dents, but under the hood has to be all spiffy,

[Allan R]

Totally up to you. If the car had it when it was delivered, it probably needed it. I've had a few overheats with my Cutlass, but that was usually my fault for overfilling the rad or a stuck thermostat (which happens once in a while).
Do I need a coolant reservoir? Probably not. But, I want it just to be on the safe side. If under the hood has to be spiffy, this might just be a little bit of clutter. In my engine bay, I think the new coolant bottle makes it look "spiffier".

If you're happy with things the way they are....leave it off.

The origin on this thread appears to be 2 isolated incidents that spurted coolant. If you've made sure your coolant is the right level, your thermostat is working right, and the rad cap is working as designed, maybe it's better just to leave well enough alone. Spend the money on gas cruisin the town and enjoying your ride.