EJ25 Beetle - please with cooling setup/bleeding

[jamesdkline]

You may remember I have a 1972 EJ25-powered beetle. It's aways been a pain to bleed but I have managed to do it a few times and have put about 300 miles on the conversion.

I just pulled apart the cooling system to install a new narrowed beam and I need your help and guidance with getting it bled. I thought I made a setup that would bleed easily but I could be totally wrong. I'd appreciate any and all help.
I have spent the better part of two days and have tried the following with no luck.
1. Jacking rear and opening filler neck in rear. This just causes the fluid to boil out
2. Jacking front and opening radiator filler neck. This causes fluid to pulse out but doesn't get warm
3. Keeping car level - opening front, rear and then both filler necks.

I can't get this thing bled. I'm willing to re-engineer the whole cooling system if that what it takes. I would appreciate any help or suggestions of different things to install. Money isn't really a factor at this point - I'll throw money at it to make it right.

Here's what I have now:
In the front is the radiator with a fill cap. The bypass port is plugged.



In the rear I have an inline filler on the hot side radiator hose. This is the highest part of the system. Here I also have an overflow tank plumbed to the overflow line on the filler. Looking at the cap, it looks like this will only get filled when the pressure forces the cap open. I'm not sure if this is right.

[dlamyle]

If I were you I'd uncap both, fill the front slowly until it won't sip anymore away then cap it. Then fill the rear slowly until it's full and then put a Spill-Free funnel on the rear and run it up to operating temperature and watch for bubbles. With this type of funnel you can rev the engine some to get things flowing. You may need to remove your deck lid for the funnel to fit under there. Also, yours may work fine as is but I had an issue where my front radiator cap was sucking air as the system cooled even though I had the over flow port plugged off. This would cause your rear overflow bottle to fill up and overflow. Again may not be an issue for you.
http://www.amazon.com/Lisle-24680-Spill ... B00A6AS6LY

[jamesdkline]

I had an issue where my front radiator cap was sucking air as the system cooled even though I had the over flow port plugged off. This would cause your rear overflow bottle to fill up and overflow. Again may not be an issue for you.

Thanks for the advice-I'll give it a try tonight. What did you do to fix the issue with your front radiator cap sucking air?

[dlamyle]

Thanks for the advice-I'll give it a try tonight. What did you do to fix the issue with your front radiator cap sucking air?

I started by using an expansion freeze plug but when I got tired of prying that out I welded on one of these
http://www.amazon.com/gp/product/B007EH ... ge_o00_s00
Then tapped this in. Works great but I do accidentally bump it on occasion.. Hot stuff!
http://www.amazon.com/gp/product/B007VR ... ge_o00_s00

[jhoefer]

What does the plumbing look like for your engine's heater circuit? It's critical to the functionality of the cooling system.

It can take several heat cycles to properly bleed. Top off at radiator first. Then top off at rear filler. Fill overflow tank. Run it up to 200 degrees F and shut it off and let it cool several hours, or overnight. Just let it run in the driveway or don't drive more than a couple blocks away as it could overheat before you get back. Once cool, it should have sucked all the coolant out of the overflow tank. Open radiator cap and top off again. Open rear fill and top off again. Refill overflow tank. Run it up to temp again and shut it off and let it cool again. Keep repeating this process. At some point, cracking open the radiator cap will have coolant leaking out immediately instead of having an air pocket, so quickly close it again and you should be done up front. The rear filler cap will need to be topped up every time the overflow tank goes dry. You will know everything is bled when the overflow tank still has coolant in it after a heat/cooldown cycle.

If you have some extra hose, you could use also a large jug of coolant as a temporary overflow reservoir. This would let the engine suck in a larger amount of coolant durning cooldown so it doesn't take as many cycles to bleed. When the level in the jug stops dropping, you know it's bled. Then just hook your normal overflow tank back up.

If the coolant temp from the crossover pipe on the engine hits 200+ degrees but the heater hose isn't hot, you've got an air pocket there. If for some reason that doesn't change after a couple heat cycles, if you can, pull the heater hose off and funnel some coolant directly into the hose to fill it. Or if it's easier, add a splice to the hose so you can fill both sides. Don't worry about spilling a bit of coolant reconnecting the hose. This might help prime the pump and get the heater circuit circulating. The heater circuit temperature controls the thermostat, so if it's airlocked, you won't get any flow through the radiator.

[jamesdkline]

What does the plumbing look like for your engine's heater circuit? It's critical to the functionality of the cooling system.

It can take several heat cycles to properly bleed. Top off at radiator first. Then top off at rear filler. Fill overflow tank. Run it up to 200 degrees F and shut it off and let it cool several hours, or overnight. Just let it run in the driveway or don't drive more than a couple blocks away as it could overheat before you get back. Once cool, it should have sucked all the coolant out of the overflow tank. Open radiator cap and top off again. Open rear fill and top off again. Refill overflow tank. Run it up to temp again and shut it off and let it cool again. Keep repeating this process. At some point, cracking open the radiator cap will have coolant leaking out immediately instead of having an air pocket, so quickly close it again and you should be done up front. The rear filler cap will need to be topped up every time the overflow tank goes dry. You will know everything is bled when the overflow tank still has coolant in it after a heat/cooldown cycle.

If you have some extra hose, you could use also a large jug of coolant as a temporary overflow reservoir. This would let the engine suck in a larger amount of coolant durning cooldown so it doesn't take as many cycles to bleed. When the level in the jug stops dropping, you know it's bled. Then just hook your normal overflow tank back up.

If the coolant temp from the crossover pipe on the engine hits 200+ degrees but the heater hose isn't hot, you've got an air pocket there. If for some reason that doesn't change after a couple heat cycles, if you can, pull the heater hose off and funnel some coolant directly into the hose to fill it. Or if it's easier, add a splice to the hose so you can fill both sides. Don't worry about spilling a bit of coolant reconnecting the hose. This might help prime the pump and get the heater circuit circulating. The heater circuit temperature controls the thermostat, so if it's airlocked, you won't get any flow through the radiator.

Thanks I'll give this a try. My heater circuit is an open loop through a heater mounted under the rear seat. I hadn't thought to check if it was hot.

At one point the top of the radiator was a little warm but just the top. So my guess is maybe an air pocket is in the return line from the radiator back to the engine? There is an uphill part where it goes over the passenger side axle.

[jamesdkline]

What does the plumbing look like for your engine's heater circuit? It's critical to the functionality of the cooling system.

It can take several heat cycles to properly bleed. Top off at radiator first. Then top off at rear filler. Fill overflow tank. Run it up to 200 degrees F and shut it off and let it cool several hours, or overnight. Just let it run in the driveway or don't drive more than a couple blocks away as it could overheat before you get back. Once cool, it should have sucked all the coolant out of the overflow tank. Open radiator cap and top off again. Open rear fill and top off again. Refill overflow tank. Run it up to temp again and shut it off and let it cool again. Keep repeating this process. At some point, cracking open the radiator cap will have coolant leaking out immediately instead of having an air pocket, so quickly close it again and you should be done up front. The rear filler cap will need to be topped up every time the overflow tank goes dry. You will know everything is bled when the overflow tank still has coolant in it after a heat/cooldown cycle.

If you have some extra hose, you could use also a large jug of coolant as a temporary overflow reservoir. This would let the engine suck in a larger amount of coolant durning cooldown so it doesn't take as many cycles to bleed. When the level in the jug stops dropping, you know it's bled. Then just hook your normal overflow tank back up.

If the coolant temp from the crossover pipe on the engine hits 200+ degrees but the heater hose isn't hot, you've got an air pocket there. If for some reason that doesn't change after a couple heat cycles, if you can, pull the heater hose off and funnel some coolant directly into the hose to fill it. Or if it's easier, add a splice to the hose so you can fill both sides. Don't worry about spilling a bit of coolant reconnecting the hose. This might help prime the pump and get the heater circuit circulating. The heater circuit temperature controls the thermostat, so if it's airlocked, you won't get any flow through the radiator.

Thanks I'll give this a try. My heater circuit is an open loop through a heater mounted under the rear seat. I hadn't thought to check if it was hot.

At one point the top of the radiator was a little warm but just the top. So my guess is maybe an air pocket is in the return line from the radiator back to the engine? There is an uphill part where it goes over the passenger side axle.

[jamesdkline]

Just wanted to close the loop on this and thank jhoefer and dlamyle for the advice.

I ended up getting new recirculating overflow tanks for the front and rear. I also added a bleeder to the hump where the line goes over the axle. After doing this it was a cinch to bleed and runs cooler now too. I just drove it 40 miles to work today with no problems.