I can remember many years ago when most cars didn't have coolant reservoirs separate from the radiator. What advantage does a separate plastic reservoir offer over just a radiator? And can a reservoir help in bleeding air out of the system after a coolant flush?
Coolant Reservoirs
- Thread starter CrackyWainwright
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The reservoir came out with the chevy vega-- some nerdy guy invented it in his garage and Chevy bought the rights! Vega had an undersized radiator and needed every surface inch it had to keep from roasting the fragile engine and leading to an oil burner.
Radiators used to just vomit excess coolant at the cap and have a normal air space of an inch or two. Air leads to corrosion of these areas. People used to regularly top off their "water" then check the antifreeze strength every November with those floaty ball thingies.
The height of the radiator cap (or sometimes surge tank) vs the rest of the plumbing helps purge air. My saturn has a pressurized "surge tank" and appropriate plumbing to a high spot on the engine (discharge to top hose) to de-aerate. But some other cars have bleeder nipples and stuff that make it less automatic, and an issue if you have to top off in the field.
The plastic bottles help because a radiator on cooldown will suck-back the coolant in there; possibly more than came out the first couple runs after a coolant fill. But you need a properly working cap to set up a siphon and keep it working. I like to overfill my bottles by an inch or two on changeout to account for the inevitable bubbles.
Radiators used to just vomit excess coolant at the cap and have a normal air space of an inch or two. Air leads to corrosion of these areas. People used to regularly top off their "water" then check the antifreeze strength every November with those floaty ball thingies.
The height of the radiator cap (or sometimes surge tank) vs the rest of the plumbing helps purge air. My saturn has a pressurized "surge tank" and appropriate plumbing to a high spot on the engine (discharge to top hose) to de-aerate. But some other cars have bleeder nipples and stuff that make it less automatic, and an issue if you have to top off in the field.
The plastic bottles help because a radiator on cooldown will suck-back the coolant in there; possibly more than came out the first couple runs after a coolant fill. But you need a properly working cap to set up a siphon and keep it working. I like to overfill my bottles by an inch or two on changeout to account for the inevitable bubbles.
I don't think my 1994 Toyota pickup with the 22-RE had a plastic coolant reservoir (just a radiator, as I recall).
But our 1980 Audi 5000S had the first plastic reservoir that I ever saw. It cracked and leaked and caused my dad much frustration and cursing. Back in the 80s, a replacement tank cost $50 from Audi . . . and we weren't about to pay that! We took a mismatched reservoir from a wrecked VW Jetta and made it work more or less.
But our 1980 Audi 5000S had the first plastic reservoir that I ever saw. It cracked and leaked and caused my dad much frustration and cursing. Back in the 80s, a replacement tank cost $50 from Audi . . . and we weren't about to pay that! We took a mismatched reservoir from a wrecked VW Jetta and made it work more or less.
Now hold on a minute! IIRC the Fords from back in the day thunderbirds forward had a pressurized tank above the radiator that actually had the radiator cap on it. My friends dad drove a early 60s station wagon that had it too. Precursor I guess...
Originally Posted By: eljefino
The reservoir came out with the chevy vega-- some nerdy guy invented it in his garage and Chevy bought the rights!
You don't give a date for this, but I suppose the Chevy Vega would put it in the 60/70's.
I'd have thought these are very similar to the radiator condensors developed for desert exploration vehicles in the 1920's and 30's.
Ralph Bagnold, FRS (The Physics of Blown Sand and Desert Dunes (1941)) who later formed the Long Range Desert Group, is often credited with its development, though it seems it may have been first employed on Model T desert patrol cars during WWI, though I havn't seen that credited to any individual.
Of course it was employed on LRDG (and later SAS) patrol vehicles in the Western Desert campaigns, and now something apparently similar in principle is in most vehicles.
The reservoir came out with the chevy vega-- some nerdy guy invented it in his garage and Chevy bought the rights!
You don't give a date for this, but I suppose the Chevy Vega would put it in the 60/70's.
I'd have thought these are very similar to the radiator condensors developed for desert exploration vehicles in the 1920's and 30's.
Ralph Bagnold, FRS (The Physics of Blown Sand and Desert Dunes (1941)) who later formed the Long Range Desert Group, is often credited with its development, though it seems it may have been first employed on Model T desert patrol cars during WWI, though I havn't seen that credited to any individual.
Of course it was employed on LRDG (and later SAS) patrol vehicles in the Western Desert campaigns, and now something apparently similar in principle is in most vehicles.
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My recall is that the radiator reservoir came into vogue with cross flow radiators, I'd say in the 1970s. The old top tank radiators obviously didn't loose cooling capacity until the coolant level dropped below the top of the core. In a cross flow radiator it has to be kept completely full for 100% of the core (i.e. cooling capacity) to be utilized. Hence the need for a reservoir.
Well... I thought that engineering but not uality oriented country...France first used the sealed coolant system on the Renault Dauphine, along with Michelin tires, lovely Cibie headlights, 4 wheel disc brakes, and many other features. Unfortunately marketing and support was not their forte. For fun compare the (more recent) Renault R-16 with the imitation, the Chevy Citation, which tried but failed to be a good imitation.
Well they may not have come with them, but just about every car going down a drag track had a reservoir. So the idea was out there long before manufacturers were installing them.
Originally Posted By: Robenstein
Well they may not have come with them, but just about every car going down a drag track had a reservoir. So the idea was out there long before manufacturers were installing them.
NHRA mandated, as well as a good way to avoid stiff penalties and fine for spilling a fluid.
Well they may not have come with them, but just about every car going down a drag track had a reservoir. So the idea was out there long before manufacturers were installing them.
NHRA mandated, as well as a good way to avoid stiff penalties and fine for spilling a fluid.
Originally Posted By: DoubleWasp
Originally Posted By: Robenstein
Well they may not have come with them, but just about every car going down a drag track had a reservoir. So the idea was out there long before manufacturers were installing them.
NHRA mandated, as well as a good way to avoid stiff penalties and fine for spilling a fluid.
Well not just in the NHRA....even non sanctions tracks and those under the old AHRA (that my dad and uncle raced in) and IHRA had it. They did not get fined back in the day, but if you puked anything on the track with any sort of regularity, the racers themselves would give you a cold shoulder.
Originally Posted By: Robenstein
Well they may not have come with them, but just about every car going down a drag track had a reservoir. So the idea was out there long before manufacturers were installing them.
NHRA mandated, as well as a good way to avoid stiff penalties and fine for spilling a fluid.
Well not just in the NHRA....even non sanctions tracks and those under the old AHRA (that my dad and uncle raced in) and IHRA had it. They did not get fined back in the day, but if you puked anything on the track with any sort of regularity, the racers themselves would give you a cold shoulder.
I have to correct myself! I was wrong about the old Tbirds having a separate coolant tank, but googling (images) 1963 Ford Country Squire I found what I was looking for. Just aft of the radiator sits a tank with the radiator cap and everything. Doesn't help with cooling the engine, just gives the expanding coolant somewhere to go. Back then radiators were built like a tank and this expansion tank looks to be the same.
Geez! Linking images is REALLY cumbersome, isn't it?
http://www.desert-vehicles.org/index.php?article_id=225
WWI Model T Desert Patrol Cars
"Water & petrol would be the governing factors of the journey and in order not to waste any of the precious liquid in the radiators of the cars, we fitted condensers to the radiator caps and closed up the overflow pipes.... By this means we saved fully 75 % of the water generally lost through boiling.”
http://www.desert-vehicles.org/index.php?article_id=206
Ford Model A Open Cab Pickup (L. Almasy 1933)
(As seen in "The English Patient", IIRC)
http://www.desert-vehicles.org/index.php?rex_resize=465w__new-29.jpg
"Cooling Fluid Condensator: A 1 gallon cooling fluid condensator is installed in the engine compartment. another one on the running board left hand side"
http://www.lrdg.de/vehicles4.htm
Long Range Desert Group
"Water Condenser - This simple yet ingenious device invented by LRDG officer Ralph Bagnold in the 1920's quickly became a standard piece of equipment for car engines, thus not only enabling the desert patrols to use their vehicles in extreme temperatures, but also greatly contributing to the reliability of car engines in general:"
http://www.lrdg.de/v_cool.jpg
BITOG stylee side note: Same site mentions the (normally water cooled) Vickers MG's were filled with hypoid oil.
Doesn't seem especially appropriate.
Whole new arena for armed thin V. thick oil conflict.
http://www.desert-vehicles.org/index.php?article_id=225
WWI Model T Desert Patrol Cars
"Water & petrol would be the governing factors of the journey and in order not to waste any of the precious liquid in the radiators of the cars, we fitted condensers to the radiator caps and closed up the overflow pipes.... By this means we saved fully 75 % of the water generally lost through boiling.”
http://www.desert-vehicles.org/index.php?article_id=206
Ford Model A Open Cab Pickup (L. Almasy 1933)
(As seen in "The English Patient", IIRC)
http://www.desert-vehicles.org/index.php?rex_resize=465w__new-29.jpg
"Cooling Fluid Condensator: A 1 gallon cooling fluid condensator is installed in the engine compartment. another one on the running board left hand side"
http://www.lrdg.de/vehicles4.htm
Long Range Desert Group
"Water Condenser - This simple yet ingenious device invented by LRDG officer Ralph Bagnold in the 1920's quickly became a standard piece of equipment for car engines, thus not only enabling the desert patrols to use their vehicles in extreme temperatures, but also greatly contributing to the reliability of car engines in general:"
BITOG stylee side note: Same site mentions the (normally water cooled) Vickers MG's were filled with hypoid oil.
Doesn't seem especially appropriate.
Whole new arena for armed thin V. thick oil conflict.
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Are not the tanks atop radiators or high up against the firewall (like with '80's era Jeep Cherokees) called header tanks?
The same name applies when they're in heating systems in homes, no? They're pressurized and assure complete fullness. Kira
The same name applies when they're in heating systems in homes, no? They're pressurized and assure complete fullness. Kira
The one thing I can't figure out is this:
If the cooling system is supposed to be sealed and pressurized, then why is the coolant reservoir vented to atmosphere via a hole on the side of it ?
If the cooling system is supposed to be sealed and pressurized, then why is the coolant reservoir vented to atmosphere via a hole on the side of it ?
The radiator is sealed and pressurized when the engine is running to whatever the psi rating of the cap is, once that psi is reached the cap allows coolant to escape. On the old cars that was down a hose on the side of the radiator that's why the coolant level cold was about an inch below the cap.
The overflow tanks just catches the overflow and as the engine cools a vacuum is created and the coolant is drawn back in, no need to pressurize it.
The tanks on modern cars that use a pressure cap and none on the radiator are not overflow tanks but an integral part of the cooling system, it increases capacity without increasing radiator size.
The overflow tanks just catches the overflow and as the engine cools a vacuum is created and the coolant is drawn back in, no need to pressurize it.
The tanks on modern cars that use a pressure cap and none on the radiator are not overflow tanks but an integral part of the cooling system, it increases capacity without increasing radiator size.
The coolant that expands into the overflow reservoir is drawn back into the radiator/cooling system when the engine cools down. This via the two-way radiator cap. The older vehicles without this feature would eventually require coolant to be added.
Originally Posted By: double vanos
I have to correct myself! I was wrong about the old Tbirds having a separate coolant tank, but googling (images) 1963 Ford Country Squire I found what I was looking for. Just aft of the radiator sits a tank with the radiator cap and everything. Doesn't help with cooling the engine, just gives the expanding coolant somewhere to go. Back then radiators were built like a tank and this expansion tank looks to be the same.
Yup and the low, sleek look means they had to get creative with where the natural "top" of the cooling system winds up. The brass-radiator Model-T look was "out."
I have to correct myself! I was wrong about the old Tbirds having a separate coolant tank, but googling (images) 1963 Ford Country Squire I found what I was looking for. Just aft of the radiator sits a tank with the radiator cap and everything. Doesn't help with cooling the engine, just gives the expanding coolant somewhere to go. Back then radiators were built like a tank and this expansion tank looks to be the same.
Yup and the low, sleek look means they had to get creative with where the natural "top" of the cooling system winds up. The brass-radiator Model-T look was "out."
Thanks Trav !
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