Does the coolant overflow need to be a closed system - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**IT Cowboy** · 02-13-2025, 10:45 PM

Or can it just flow and suck from a bottle? My current tank by the battery broke and it was old and just the hose stuck into the tank and the lid was loose or non-existent. I am probably going to order the washer tank to replace it but I am wanting to know if I can mount a bottle somewhere as a get me by.

Classics Fan · 02-13-2025, 11:08 PM

The coolant recovery system is a simple bottle for expansion collection when hot. As the engine cools coolant is sucked back into the radiator. A temporary plastic bottle can be used until you replace the OEM bottle. The hose from the radiator needs to extend close to the bottom of the collection bottle.

**IT Cowboy** · 02-13-2025, 11:22 PM

I just re-purposed my washer fluid container as my wipers aren't working right now anyway. I re-mounted it on the passenger side fender and it already has a cap with a nipple and suction tube in it. I have seen older trucks with a Jack Daniels bottle and cork.

**dmjlambert** · 02-13-2025, 11:30 PM

The lid or cork is not sealed. It is vented.

**Richard** · Yesterday, 04:01 AM

Coolant recovery tank should be open to atmosphere. Not present on stock 67-72 trucks, but feel free to add one. I will have one in my truck.

**old51sedan** · Yesterday, 09:18 AM

On my truck I bought a tank from amazon, mounted it on the firewall, it's not original, but it works fine, easy to see and out of the way.

**Stocker** · Yesterday, 09:36 AM

You probably already know that you'll need a radiator cap for a closed system. A conventional cap won't suck the coolant from the overflow tank as it cools.

**A1971Blazer** · Yesterday, 11:10 AM

I bought a tank from a member here it works great.
pictures here https://67-72chevytrucks.com/vboard/...d.php?t=855434

**jaros44sr** · Yesterday, 12:44 PM

Quote:

Originally Posted by old51sedan

On my truck I bought a tank from amazon, mounted it on the firewall, it's not original, but it works fine, easy to see and out of the way.

Nice engine bay

**IT Cowboy** · Yesterday, 03:07 PM

I have the AC in mine so I am limited where I can mount a tank. I posted earlier that I just robbed the wiper tank off the driver's side and put it on the fender by the battery.

jhe.1973 · Today, 12:23 PM

Quote:

Originally Posted by Stocker

You probably already know that you'll need a radiator cap for a closed system. A conventional cap won't suck the coolant from the overflow tank as it cools.

Thanks for the tip Stocker! I didn't know of the closed system cap.

How do I specify one that will work with a 69 radiator? I.E what year(s) etc.?

**old51sedan** · Today, 12:59 PM

Quote:

Originally Posted by Stocker

You probably already know that you'll need a radiator cap for a closed system. A conventional cap won't suck the coolant from the overflow tank as it cools.

Yes, was aware of that, but a good point to let everyone know. I would have put it by the battery, but have some extra wiring there from the vintage air.

**Stocker** · Today, 01:09 PM

Quote:

Originally Posted by jhe.1973

Thanks for the tip Stocker! I didn't know of the closed system cap.

How do I specify one that will work with a 69 radiator? I.E what year(s) etc.?

Not sure what year(s) closed systems became standard. Caps for a closed system have two rubber seals -- others have just one.

I just went to my local NAPA store & told them what I wanted.

**MikeB** · Today, 01:39 PM

After searching this forum a couple years ago, here's what I used:
OER coolant recovery tank #551448
Dorman vented cap #82590
3/8 ID x 9/16 OD silicon tubing from Amazon

Was even able to use an existing hole on the inner fender.

Works great. No more overflow to the pavement on hot days!

jhe.1973 · Today, 03:51 PM

Quote:

Originally Posted by MikeB

After searching this forum, here's what I used:
OER coolant recovery tank #551448
Dorman vented cap #82590
3/8 ID x 9/16 OD silicon tubing from Amazon

Was even able to use an existing hole on the inner fender.

Works great. No more overflow to the pavement on hot days!

I really like this with how clean it appears! Too bad I didn't see it before I did my version!

jhe.1973 · Today, 03:55 PM

Hi Everyone,

I've been trying to post a rather long reply for several hours and have been kicked off several times or received the notice that the server is too busy and then be kicked off when I try later!

I've saved the text but I have to hunt up the photos each time so I hope to get back as soon a possible!

jhe.1973 · Today, 04:38 PM

Hi Everyone,

I've finally given up! Too much of my day has been wasted and I need to get to work. I can try again late tonight when things aren't so busy.

I have a 1986 4WD K20 chassis for another project. Does anyone know if the steering box and pump will fit this wrecker?

It's still hooked together so I can swap the assembly if the pitman from the wrecker will fit the other box.

I'll post this question in another thread to see if it gets more views.

**Rust_never_sleeps** · Today, 05:22 PM

Those that have done this, what's the approximate volume required for this kind of setup?
Presumably less than 750ml, since a JD bottle works ;-)

02-13-2025, 10:45 PM	#1
IT Cowboy Active Member Join Date: Jan 2025 Location: Clarkdale, Arizona in a van down by the river Posts: 175	Does the coolant overflow need to be a closed system Or can it just flow and suck from a bottle? My current tank by the battery broke and it was old and just the hose stuck into the tank and the lid was loose or non-existent. I am probably going to order the washer tank to replace it but I am wanting to know if I can mount a bottle somewhere as a get me by. __________________ '72 C10 / 402 ___________________________________________ Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

02-13-2025, 11:08 PM	#2
Classics Fan Registered User Join Date: Jan 2018 Location: Anacortes. WA Posts: 145	Re: Does the coolant overflow need to be a closed system The coolant recovery system is a simple bottle for expansion collection when hot. As the engine cools coolant is sucked back into the radiator. A temporary plastic bottle can be used until you replace the OEM bottle. The hose from the radiator needs to extend close to the bottom of the collection bottle.

02-13-2025, 11:22 PM	#3
IT Cowboy Active Member Join Date: Jan 2025 Location: Clarkdale, Arizona in a van down by the river Posts: 175	Re: Does the coolant overflow need to be a closed system I just re-purposed my washer fluid container as my wipers aren't working right now anyway. I re-mounted it on the passenger side fender and it already has a cap with a nipple and suction tube in it. I have seen older trucks with a Jack Daniels bottle and cork. __________________ '72 C10 / 402 ___________________________________________ Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

02-13-2025, 11:30 PM	#4
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,939	Re: Does the coolant overflow need to be a closed system The lid or cork is not sealed. It is vented.

Yesterday, 09:18 AM	#6
old51sedan Senior Member Join Date: Oct 2015 Location: Williamston, Mi Posts: 889	Re: Does the coolant overflow need to be a closed system On my truck I bought a tank from amazon, mounted it on the firewall, it's not original, but it works fine, easy to see and out of the way. Attached Images

Yesterday, 04:01 AM	#5
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,930	Re: Does the coolant overflow need to be a closed system Coolant recovery tank should be open to atmosphere. Not present on stock 67-72 trucks, but feel free to add one. I will have one in my truck. __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

Yesterday, 09:36 AM	#7
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,777	Re: Does the coolant overflow need to be a closed system You probably already know that you'll need a radiator cap for a closed system. A conventional cap won't suck the coolant from the overflow tank as it cools. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

Yesterday, 11:10 AM	#8
A1971Blazer Senior Member Join Date: Nov 2013 Location: East Tennessee Posts: 2,216	Re: Does the coolant overflow need to be a closed system I bought a tank from a member here it works great. pictures here https://67-72chevytrucks.com/vboard/...d.php?t=855434 __________________ 1967 C10 Step side 1968 C10 Step side 1970 Chevrolet K/5 Blazer 1972 Chevrolet K/5 Blazer .............

Yesterday, 03:07 PM	#10
IT Cowboy Active Member Join Date: Jan 2025 Location: Clarkdale, Arizona in a van down by the river Posts: 175	Re: Does the coolant overflow need to be a closed system I have the AC in mine so I am limited where I can mount a tank. I posted earlier that I just robbed the wiper tank off the driver's side and put it on the fender by the battery. __________________ '72 C10 / 402 ___________________________________________ Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

Today, 01:39 PM	#14
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,646	Re: Does the coolant overflow need to be a closed system After searching this forum a couple years ago, here's what I used: OER coolant recovery tank #551448 Dorman vented cap #82590 3/8 ID x 9/16 OD silicon tubing from Amazon Was even able to use an existing hole on the inner fender. Works great. No more overflow to the pavement on hot days! Attached Images __________________ Mike 1969 C10 LWB -- owned for 36 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; Today at 04:41 PM.

Today, 03:55 PM	#16
jhe.1973 Registered User Join Date: Jul 2024 Location: N.E. Arizona Posts: 73	Re: Does the coolant overflow need to be a closed system Hi Everyone, I've been trying to post a rather long reply for several hours and have been kicked off several times or received the notice that the server is too busy and then be kicked off when I try later! I've saved the text but I have to hunt up the photos each time so I hope to get back as soon a possible! __________________ Best wishes to ya’ll. Sincerely, Jim "To invent you need a good imagination and a pile of junk" - Thomas Edison "I've always wanted to get a job as a procrastinator - but, I keep putting off looking for one - I guess I'll never realize my life's dream - so sad." - Me My C30 wrecker build/repair/update thread: https://67-72chevytrucks.com/vboard/...d.php?t=855904

Today, 04:38 PM	#17
jhe.1973 Registered User Join Date: Jul 2024 Location: N.E. Arizona Posts: 73	Re: Does the coolant overflow need to be a closed system Hi Everyone, I've finally given up! Too much of my day has been wasted and I need to get to work. I can try again late tonight when things aren't so busy. I have a 1986 4WD K20 chassis for another project. Does anyone know if the steering box and pump will fit this wrecker? It's still hooked together so I can swap the assembly if the pitman from the wrecker will fit the other box. I'll post this question in another thread to see if it gets more views. __________________ Best wishes to ya’ll. Sincerely, Jim "To invent you need a good imagination and a pile of junk" - Thomas Edison "I've always wanted to get a job as a procrastinator - but, I keep putting off looking for one - I guess I'll never realize my life's dream - so sad." - Me My C30 wrecker build/repair/update thread: https://67-72chevytrucks.com/vboard/...d.php?t=855904

Today, 05:22 PM	#18
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 670	Re: Does the coolant overflow need to be a closed system Those that have done this, what's the approximate volume required for this kind of setup? Presumably less than 750ml, since a JD bottle works ;-) __________________ 1970 C10 Custom longbed 350/350 Code: __ ______\|__]\____ ....\|___(o)_____(o)_]



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