How to bleed / test your Vanagon coolant system-$2 solution.

[danfromsyr]

I do this with a garden sprayer full of anti-freeze instead of the beloved libby bong..
I find it much less prone to (user) error. though still not completely fool proof

and YES I carry a hose with a schrader valve in my travel 'kit' for just this purpose. a quick hit with a tire pump and moves the air out of the radiator easily.. how many travel with a libby bong? and don't tell the cops.

the tubeless schrader valve is also handy for bleeding the brakes/clutch
I install one into a spare brake reservoir cap and pump to 3-5psi then open the bleeder a crack.. voila.. don't let the reservoir go empty.. check frequently.
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[Terry Kay]

I do believe that blowing 20 psi into a cooling system is asking for trouble in area's of the cooling system you may not want to know if they are marginal.

Weakest link to disaster with bigger than the system was designed to hold pressure?
The water jacket seals.
12 -15 pounds would be it.

You don't need 20 psi pressure to locate a weep at a connection in a hose or the radiator.
Hell--5 lbs would show you a leak.

20 lbs is nuts and could lead to more problems than you were looking for.
What's with the Canadian big air pressure testing of AC systems & cooling systems?
Why can't you operate within normal parameter's, and with some sort of usual testing equipment?
Like a normal cooling system pressure testing devises--??
Or is side stepping the correct tools just the way it plays out in your garage?
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T.K.

[danfromsyr]

I do agree with Terry on that one..

I tend to toss in 10PSI (easy to view on my gauge) and see that it holds it for an minute/hour/overnight

you really don't want to rupture your heater core (or cylinder gaskets.)
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[insyncro]

10-12lbs is what I test with.
Crank it up and blow a few seals you will.

[Terry Kay]

I totally forgot about the front ( or rear for that matter ) heater cores.

Boy--would I really be kicking myself in the butt for blowing a hole in the front core cause I was pumping all kinds of unnecessary pressure into my cooling system, to find a pin hole leak somewhere else--ouch--X3--

You don't have to go nuts here with the air pressure in the cooling system to find a coolant weeping area.

The garden sprayer is a decent way to go about this--
I have a Snap On testing set up, and besides being able to check out the system with safe pressures, I can test the pressure caps too--and bleed the coolant besides that---

Short cuts are a neat way to go--but I would stay away from the compressor big psi method without blinking an eye.

That $2.00 "solution" could very well lead to all kinds of unwarrated $$$$ expenditures.
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T.K.

[denwood]

The system is design to take 15 psi hot, all day long. I'll leave it at that For anyone anxious about pushing the limit, don't use more than 15. Thanks for your feedback Dylan. I'll have a mod add the note about exceeding rated pressure at one's own risk, it's good advice.

With respect to why I chose to use 20 psi, here it is. My van was losing coolant over a longer period (post conversion), with no visible leaks idling, hot. Whatever was leaking, was only doing it hot under driving conditions. No leaks were evident at 15 psi cold. Applying 20 psi, it was evident that my van was suffering the infamous plastic pipe/metal insert issue up front. Since replacing those parts, my slow coolant loss issue was resolved. Your mileage may vary.
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Cheers,
Dennis Wood
The Grape

[Terry Kay]

PTL Baby Jesus!

That 5 psi bump in pressure healed your cooling system issue.

IT'S TRUELY A MIRACLE!

Can I hear a Hallelujah !

I don't think so.
If it leaks at 20, it was leaking at 15, you
just didn't see it from the side of the van untill it was tossing the fluid 2 ft. beyond the tube.
And I for sure wouldn't want to be taking down other possibly iffy components in the process at anything more than the cap pressure.


Amen.
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T.K.

[Ahwahnee]

Posted sometime in the past but I'll put here for general info.

How I let it bleed, using an electric fuel pump with a bit under 5 psi:

Uses the existing hose to the pressure cap, run it until coolant comes out of the radiator, close the bleeder. No drama.

I do have a little hole in the thermostat - not sure this would work well without that.

I don't rely on it to look for leaks but then I have none. I suppose if there was a leak 5# might be enough to reveal it.

[Terry Kay]

Hold on till I get the part number of a sealed cooling system pressure testing tool that tests at 5 psi, but also refills the entire system with the flip of a lever, & it's a. small portable unit.

Your on the right page, the only difference is your on 12 volts@ 5 psi not on an air line which is plenty for filling the system & checking for leaks.
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T.K.

[denwood]

Aw, that's a great solution for filling. Standard practice for pressure testing a coolant system though is to do it at the cap rated pressure...as that is the pressure the system will operate at, 15 psi. To be honest, my little solution was done first to just pressure test and find a leak. The fact that you could bleed at the same time came logically after. After doing it a few times, it works a treat.

Your engine bay btw gets my "super clean" award
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Cheers,
Dennis Wood
The Grape

[Terry Kay]

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Here is the pressure bleeder & fill tool.
It functions off of line air from your air compressor.
It has a safety operational margin that would not allow a guy to blow his system up with insane pressure.
If you don't have a compressor, a weed sprayer, or fuel pump ( great idea) could be used to get the same results--and be able to fill the sysyem back up when you were done checking for leaks.
I know the sprayer has been used for years --with good results , and not at all jepordizing the coolant system components with crazy high air pressure.
All of the above are real fast way of getting two operations done at once , quickly, efficianlty, and safely.
I do like the suction fill operation of this tester.
Drop a hose into a 5 gallon bucket , and pressure fill the system after you've checked for leaks.
No Bong--no incline or jacked up fills, or crazy bleeding, just simple.
A No-Brainer--
A 2 buck tool might cost you more than you bargained for.
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T.K.

[denwood]

I've had KamK add this note to the first post:

"Edit/Note: The system pressure is rated at 15 psi; exceeding 15 psi during a pressure test should only be done if, like me, you're looking to stress the system a bit"

Interesting that BMW used 30 psi for their cooling systems in models 1982 to 2006, and have a few vendors offering retrofit 20 psi caps to extend rad life. Nog, Awahnee, Dan, thanks for posting your ideas on fluid filling. I'm sure a few folks will end up using variations on the theme. Productive discussion for sure.

Any of these methods do rely on one basic element, maybe an obvious one: never remove the expansion tank cap while the rad bleed bolt/valve is open...unless you're trying to drain the system. To illustrate why, drop a straw into a glass of water. Put your finger on the open end of the straw and pull the straw up, keeping the fluid end just immersed. Release your finger. You'll see the effect of air pressure/vacuum on a water column. This principle is what keeps the fluid in your rad, consistently at a level higher than the rad cap. Your finger on the straw is playing the role of the rad bleed bolt/valve. (sorry previous life as staff scientist with Science North, ha)
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Cheers,
Dennis Wood
The Grape

[gpacetti]

I've read most of these Cooling system postings. I understand the Mr.Denwood has used or still using the VanCafe Auto trans cooler. I am using the same cooler in my 85 Vangn but since doing so I've had very poor bleeding results(I'm also using a bicycle pump bleed method) and definitely overheating issues. The old cooler hoses are now cut back to 2 eight inch long capped dead-ends. It occurred to me recently maybe they're causing a vacuum type problem and should be attached to each other creating a small loop.

Can I get feedback from someone particularly Mr. Denwood since I believe he's using the same cooler. I live in Alaska.....greg

[denwood]

Greg, my auto trans and oil cooler hoses were both cut back and blocked, but remember I had a 50 degree ABA conversion with essentially the 82 diesel hoses. I did not connect the hoses. That said, I had zero issues bleeding with the pressure method regardless of configuration. If you're seeing consistent air in the system, you may want to check for combustion gasses in your coolant.
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Cheers,
Dennis Wood
The Grape

[Deacon_Brown]

I replaced my thermostat this weekend on my '87 Westy (PO had jammed a nut into the spring keeping it perpetually open). I panicked as I realized I would have to bleed the coolant system. Came to TheSamba and thought about building a Libby Bong; opted for the garden sprayer method. I can't recommend that method enough.

Total cost - $10
Total time - 5 minutes

I did have help, my 6-year-old stood by the radiator and told me 'dad, air is coming out'

[djkeev]

[Gizmoman]

If a guy had a tire valve as a "T" in the line to the overflow res., the pressure cap would serve as protection from over pressure, It would also test the cap.

Good write up.
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[wehrbüchse]

I'm confused: how can I bleed air from the radiator on a flat surface by pressurizing at 13lbs PSI through a faulty reservoir cap unless the coolant is hot enough to open the thermostat?

Anyway, can someone point me to an image of this garden sprayer setup? Thanks guys.

[danfromsyr]

from this thread
https://www.thesamba.com/vw/forum/viewtopic.php?t=634589

[Ahwahnee]

If you want to use your installed cap you can skip the valve and connect directly to the overflow outlet on the blue cap. That is how I fill using a 3-4 psi fuel pump though pressure could be tested the same way.