TheSamba.com :: View topic - Alternative (DIY) Aluminum coolant Expansion tank

Thu Dec 24, 2020 4:34 pm

Look forward to your progress skills!

Can you post a link to your bung source?

We arrived home from Christmas Eve brunch with my daughter to find yet another package sitting in the rain on my porch.

This one from McMasterCarr held the aluminum fittings for the Joes expansion tank ......

Dave

Thu Dec 24, 2020 6:01 pm

Skills,
you don't have to have the coolant jug above the radiator for a single tank system. the bubble in the tank won't leave and migrate to the radiator.
it stays in the bottle in the engine compartment. air can't go 'down' through the coolant. it's a trap.
and the coolant bottle won't get over filled when you open it. the radiator coolant that is higher can't drop down to fill/overflow the tank as there's no air to replace it.. it stays in 'suspension' in the radiator. like water in a straw when you put your finger over the top.

this is why the radiator has it's own bleeder. the coolant tank and radiator are treated separately.

we run the spherical VW pressure coolant tanks only in our engine swaps. the coolant level probes work with the oem level relay system.

skills@eurocarsplus wrote: timely post, as i have been working on the coolant layout for my subaru swap.

anyway, the vanagon needs (in my opinion) a overflow unless you can put the coolant jug higher than the radiator. then, you can run an expansion tank, that's what i do for the bay swaps:

anyway, when i use the tank pictured, it doesn't get filled to the top. only the bottom 3/4-1" has coolant in in cold. as the engine heats, it will rise almost to the seam. works great.

i'm working on my own aluminum tank and actually found weld in bungs for the stock coolant level sensor. all in, i'll probably be at 100 bux for all the bits.

we'll see how mine turns out, still a while before i get that far. i really had an issue paying the asking price from the boutique stores only to have to modify it further for my application

Thu Dec 24, 2020 6:55 pm

djkeev wrote: Look forward to your progress skills!

Can you post a link to your bung source?

yea, i'm looking forward to progress too :lol:

the bung is custom made. the 2 pin sensor is a 30mm thread, and very uncommon. once i get it in my hand and know it will work i'll post the results.

the tank is a 30.00 tank from fleabay and has the jap cap sized radiator cap, it was some universal one for honda/acura

https://www.ebay.com/itm/1L-Universal-Aluminum-Rad...2849333368

i sent an offer for 25 bux and he bit. jokes on me though...it will probably take 2 years to get here and leak :lol:

i plan on mounting it where 16CVs is... but that is subject to change. i don't want to muddy your thread with my subaru nonsense but i don't plan on the reversed manifold many run... if i do this as i have planned in my head the tank can remain right where the original plastic one does

danfromsyr:

you're 100% right. the finger over the straw analogy did it for me. in theory, i could run the expansion tank i use on the bays, keep the level low and let it grow with heat like i described in my last post. then there would be no need for a separate overflow tank.

so i assume when you guys run the sphere the coolant must grow in them as well?

Thu Dec 24, 2020 7:20 pm

this thread is inspiring me to finally fix my leaking tank. Just ordered these, plan on putting them back to back. Wil have to weld some bungs. I'll send pics when done...which will be a number of weeks.

https://www.amazon.com/gp/product/B086P9LX81/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B07DT3M5WZ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Fri Dec 25, 2020 6:05 am

Vanis13, thanks for those links.

I had looked at those you posted but not having a TIG I knew that I couldn't easily modify them to work.
The one with the sight glass on the side just seemed to add a fail possibility point. These sight glasses and I have had a less than an ideal relationship over the decades.
I have sight glasses like that in the commercial kitchen I maintain...... fragile little bugger! I've also had them in water based home heat systems, they were so prone to failure that I kept a spare sight glass and seals on hand.
On the unit with the sight glass, The rubber 90's seem proprietary too.

I also looked at this one........

https://www.amazon.com/dp/B08N5P9MY9/ref=sspa_dk_d...NrPXRydWU=

The Joes tank I chose seemed like the best fit without serious modifications.
Of course as I gather bits the savings over GoWesty's tank continues to shrink significantly!
But I'm enjoying the process. I'll end up with a quality tank saving a few $ over the current offering PLUS not have that leak prone OEM plastic level sender.

I don't mean this thread to be just my vision of alternative tanks using Joes tank but let's flesh out other options as well!

I think the ultimate goal is to get a DIY quality off the shelf replacement tank at a price point that makes the jump from cheap failure prone plastic repop to a metal one easy and attractive.
Another goal is to get rid of that silly plastic screw on finicky top where you have to disconnect the overflow tank hose to top it off.

Merry Christmas everyone!

Dave

Fri Dec 25, 2020 8:18 am

I hear you about the level indicator. We'll see how that works. If it fails, I'll just plug those holes. BTW, those plastic corner fittings are not proprietary. It is a common fitting used many places including material handling. My overflow tank has a hole in it (covered with duct tape now) so replacing it has been on my list.

Fri Dec 25, 2020 8:20 am

Dave - don't forget to take the engraver and sign and date that tank! it'll be worth a fortune on eBay 20 years from now.

nice job, it looks perfectly functional. i'd consider a level sensor like this one. a welded bung would be best but a backing nut and silicone would probably work.
https://www.amazon.com/Sensor-Stainless-Liquid-Electrode-Boiling/dp/B082FK37QX

Fri Dec 25, 2020 9:21 am

vanis13 wrote: I hear you about the level indicator. We'll see how that works. If it fails, I'll just plug those holes. BTW, those plastic corner fittings are not proprietary. It is a common fitting used many places including material handling. My overflow tank has a hole in it (covered with duct tape now) so replacing it has been on my list.

I think I have a spare overflow tank, PM me your address.
I'm going to Jersey in the next few days, if I have it, it is yours!

Dave

Fri Dec 25, 2020 10:34 am

djkeev wrote: vanis13 wrote: I hear you about the level indicator. We'll see how that works. If it fails, I'll just plug those holes. BTW, those plastic corner fittings are not proprietary. It is a common fitting used many places including material handling. My overflow tank has a hole in it (covered with duct tape now) so replacing it has been on my list.

I think I have a spare overflow tank, PM me your address.
I'm going to Jersey in the next few days, if I have it, it is yours!

Dave

Very nice Dave! I'll PM you my address if needed. I'll have these tanks on Tuesday (love Prime) and plan putting the alum expansion tank right next to the pressure tank so it may be a nice install...otherwise, I'll definitely take you up on that!

Fri Dec 25, 2020 6:35 pm

Are the Westy water tank level sensors something super hard to reproduce? Seems like there must be more of that kind of sensors out there.

Fri Dec 25, 2020 6:41 pm

bobbyblack wrote: Are the Westy water tank level sensors something super hard to reproduce? Seems like there must be more of that kind of sensors out there.

I've had the OEM VW level sensors plastic crack along the probes and then seep up the metal portion and ooze out the electrical plug.
Granted, they are cheap, but you gets what you pays for.

There are better probes, I'm going to use one designed for 18 wheelers.

This is one of the pluses for ditching VWs pressure tank system, this is also why GoWestys tank held no appeal to me. They use the OEM level sensor.

Dave

Sat Dec 26, 2020 4:40 pm

I used one of these for my svx conversion https://www.jegs.com/i/Moroso/710/63773/10002/-1?g...78QAvD_BwE

I added a bung for the level sensor and another nipple on the side. I plugged the one on the bottom.

Sat Dec 26, 2020 6:38 pm

skills@eurocarsplus wrote:

i plan on mounting it where 16CVs is... but that is subject to change. i don't want to muddy your thread with my subaru nonsense but i don't plan on the reversed manifold many run... if i do this as i have planned in my head the tank can remain right where the original plastic one does

More than a few of us do it that way... It works well for me!

Sun Dec 27, 2020 9:16 am

djkeev wrote: bobbyblack wrote: Are the Westy water tank level sensors something super hard to reproduce? Seems like there must be more of that kind of sensors out there.

I've had the OEM VW level sensors plastic crack along the probes and then seep up the metal portion and ooze out the electrical plug.
Granted, they are cheap, but you gets what you pays for.

There are better probes, I'm going to use one designed for 18 wheelers.

This is one of the pluses for ditching VWs pressure tank system, this is also why GoWestys tank held no appeal to me. They use the OEM level sensor.

Dave

I'm actually trying to put a new notion into this mix. Not the coolant level sensor. I'm saying the Westy Water Tank level sensor(s). There must be a way to recreate, or approximate that for your coolant level, including the LED level indicators. Of course, it would only be useful when engine is off, due to the agitation in that tank.

Also, seems nobody took me up on how much flow there is in the tank.. I mean REALLY --- LOOK in the stock tank with the Blau cap off, and rev the throttle to 3K or so. LOOK at it!!! Agitation. If your coolant level is so low that the flow isn't hitting that stock sensor and the dash light is going off, man, that is already way way late in the game.

I'm not sure of what it means on my 2.1 stock system, but when I do drain/change/bleed coolant, and rev to 3K, I can pour more coolant, maybe not quite a pint, into the tank before putting the cap back on. The water pump seems to suck the level down a bit. BUT, then it will pee a bit back out into the overflow. Gets me wondering how much 'suck' happens every time I go from idle to highway speeds.

Sun Dec 27, 2020 10:48 am

Dave[/quote] Gets me wondering how much 'suck' happens every time I go from idle to highway speeds.[/quote]

For what it is worth, I have a mechanical "pressure gauge" on the cooling system of the ALH engine in my 84 Vanagon. I installed a fitting high on the round expansion tank (OE to the Jetta donor). From there, I used a 1/4 inch nylon pipe all the way up to the lower dash to the gauge. The system generally operates between 7 and 9 PSI.

As the engine warms up, the pressure begins to go up. . ... As for "suction" well, I can rev the engine and for a couple of seconds the pressure gauge will drop at least 2 psi and then bounce back. The pipe coming out of the bottom of the tank is quite similar as the one on the 2.1 WBXer as it is almost a direct connection to water pump housing! .... impressive suction in my opinion!

Sun Dec 27, 2020 11:42 am

Another idea if you aren't into welding on the universal tanks - using an AN bulkhead fitting

(On my phone, sorry for the long link)
https://www.summitracing.com/parts/vpe-16892?seid=...NtEALw_wcB

That's a -6 but you can get them in huge -16+ sizes as well to fit the larger coolant hoses.

If you have enough room to get a wrench into the inside through the pressure cap you can add these anywhere. Then adapt from AN to barb, or hose end as needed
You can get the fittings with plastic or aluminum crush washers, and a little dab of permatex oughta keep them from ever leaking.

Mon Dec 28, 2020 5:51 am

valvecovergasket wrote: Another idea if you aren't into welding on the universal tanks - using an AN bulkhead fitting

(On my phone, sorry for the long link)
https://www.summitracing.com/parts/vpe-16892?seid=...NtEALw_wcB

That's a -6 but you can get them in huge -16+ sizes as well to fit the larger coolant hoses.

If you have enough room to get a wrench into the inside through the pressure cap you can add these anywhere. Then adapt from AN to barb, or hose end as needed
You can get the fittings with plastic or aluminum crush washers, and a little dab of permatex oughta keep them from ever leaking.

I had brought up the bulkhead fitting idea previously.
Some felt that the known failure rate of them leaking after awhile was a concern.

I do like that one with the sealing rings though........

Dave

Dave

Tue Dec 29, 2020 2:59 pm

I keep running to the mailbox hoping for the VAG VW rods I ordered, but today brought the Low Coolant Sensor.

Waiting on the bung for this sender to arrive and then I can assemble the tank for use.

The screw on the side I believe to be a grounding screw?

Dave

Tue Dec 29, 2020 3:45 pm

since the coolant level circuit is calibrated to the twin rods in the OEM sensor, you may have to 'tune' this one a bit by trimming off the nylon sheath to get the conductivity the circuit wants to see. if it ends up being plenty sensitive with just the tip, i'd cut the rod short so it gives you a higher level reading.

Tue Dec 29, 2020 3:53 pm

DanHoug wrote: since the coolant level circuit is calibrated to the twin rods in the OEM sensor, you may have to 'tune' this one a bit by trimming off the nylon sheath to get the conductivity the circuit wants to see. if it ends up being plenty sensitive with just the tip, i'd cut the rod short so it gives you a higher level reading.

I put RMW's tank on and it has a one terminal probe. No mention was made of adjustments.
I also had no leaks and have absolutely no idea if their level probe even works!

Dave