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westyventures
Samba Member
Joined: December 29, 2004
Posts: 2306
Location: Oregon Outback
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 Posted: Wed Aug 13, 2014 11:42 am Post subject: |
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The heat exchanger helps get the engine and oil up to operating temperature quicker and maintains it there. An external oil cooler, to be most efficient, needs high-pressure airflow (i.e. at the front) to achieve best cooling. The radiator already is there and can handle all the heat rejection by itself.
Here are a few filthy photos, I haven't washed the engine since an 8000-mile trip last month, tons of dirt roads and dust! One correction to what I said earlier: The connection removed from the bottom hose - I actually teed into the expansion tank return, not the J hose. But either this or the J hose returns to the same port in the water pump so should give the same results.
Since mine all all conversions, the aux pump was never added as I don't see any point in it. No real benefit I can think of.
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Waldi
Samba Member
Joined: February 28, 2014
Posts: 1752
Location: Germany
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Waldi
Samba Member
Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Wed Aug 13, 2014 2:01 pm Post subject: |
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| westyventures wrote: |
The heat exchanger helps get the engine and oil up to operating temperature quicker and maintains it there. An external oil cooler, to be most efficient, needs high-pressure airflow (i.e. at the front) to achieve best cooling. The radiator already is there and can handle all the heat rejection by itself.
Here are a few filthy photos, I haven't washed the engine since an 8000-mile trip last month, tons of dirt roads and dust! One correction to what I said earlier: The connection removed from the bottom hose - I actually teed into the expansion tank return, not the J hose. But either this or the J hose returns to the same port in the water pump so should give the same results.
Since mine all all conversions, the aux pump was never added as I don't see any point in it. No real benefit I can think of.
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The water-oil-temp-exchanger is good for heating up the oil.
But like he ist conected original to the water system, the heat doesnt go to the front waterradiator, it goes direkt to the engine.
So a extra mocal oilcooler is a must for our backengines.
My oil temperature in AAZ never goes over 100, even with a 2,5t trailer and hils. |
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
Location: Where?
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| Posted: Wed Aug 13, 2014 2:10 pm Post subject: |
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| westyventures wrote: |
| I actually teed into the expansion tank return, not the J hose. But either this or the J hose returns to the same port in the water pump so should give the same results. |
I assume what you are calling the J hose is the bypass hose from the center of the head to the center port on the water pump. That port is closed when the thermostat is opened and fully closed when the thermostat is fully open. The pressure tank is connected to the top port of the water pump which is always open.
If the cooler is plumbed with the stock connection on the 4-way hose that runs from the center of the head to the radiator and the other connection is plumbed to the bypass hose, then there will be a small amount of flow through the cooler parallel to the flow through the bypass hose. Once the thermostat is fully open there would not be any flow through the cooler.
If the cooler is plumbed with the stock connection to the 4-way hose and the output from the cooler plumbed to the return from the pressure tank to top hose, then there would always be flow parallel to the flow through the heater.
A flow path very similar to the second option, that would likely both improve oil cooling and improve heat output from the heater would be to plumb the oil cooler in series with the heater loop. End of head to cooler, other cooler connection to the hose that normally attaches to the end of the head. |
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Waldi
Samba Member
Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Wed Aug 13, 2014 2:20 pm Post subject: |
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| Andrew A. Libby wrote: |
| westyventures wrote: |
| I actually teed into the expansion tank return, not the J hose. But either this or the J hose returns to the same port in the water pump so should give the same results. |
I assume what you are calling the J hose is the bypass hose from the center of the head to the center port on the water pump. That port is closed when the thermostat is opened and fully closed when the thermostat is fully open. The pressure tank is connected to the top port of the water pump which is always open.
If the cooler is plumbed with the stock connection on the 4-way hose that runs from the center of the head to the radiator and the other connection is plumbed to the bypass hose, then there will be a small amount of flow through the cooler parallel to the flow through the bypass hose. Once the thermostat is fully open there would not be any flow through the cooler.
If the cooler is plumbed with the stock connection to the 4-way hose and the output from the cooler plumbed to the return from the pressure tank to top hose, then there would always be flow parallel to the flow through the heater.
A flow path very similar to the second option, that would likely both improve oil cooling and improve heat output from the heater would be to plumb the oil cooler in series with the heater loop. End of head to cooler, other cooler connection to the hose that normally attaches to the end of the head. |
I hope i understand u right, but if u connect the oilcooler in series with the heater, it works only if the heater is on. |
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westyventures
Samba Member
Joined: December 29, 2004
Posts: 2306
Location: Oregon Outback
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| Posted: Wed Aug 13, 2014 4:05 pm Post subject: |
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| Andrew A. Libby wrote: |
I assume what you are calling the J hose is the bypass hose from the center of the head to the center port on the water pump. That port is closed when the thermostat is opened and fully closed when the thermostat is fully open. The pressure tank is connected to the top port of the water pump which is always open.
If the cooler is plumbed with the stock connection on the 4-way hose that runs from the center of the head to the radiator and the other connection is plumbed to the bypass hose, then there will be a small amount of flow through the cooler parallel to the flow through the bypass hose. Once the thermostat is fully open there would not be any flow through the cooler.
If the cooler is plumbed with the stock connection to the 4-way hose and the output from the cooler plumbed to the return from the pressure tank to top hose, then there would always be flow parallel to the flow through the heater.
A flow path very similar to the second option, that would likely both improve oil cooling and improve heat output from the heater would be to plumb the oil cooler in series with the heater loop. End of head to cooler, other cooler connection to the hose that normally attaches to the end of the head. |
I wasn't thinking clearly when I wrote that. The 'top' port of the water pump goes to the head output flange via the J-pipe. That is the one that is closed when the thermostat opens. So def. no connection into the J hose! The lower of the two ports goes to the expansion tank and that is what I teed into, because that flows all the time regardless of thermostat open/close. The constant flow through the oil cooler is the reason, I think, why the oil temperature is so stable now and only goes up slightly as the coolant temp goes up during extended hard climbs. I had thought about plumbing it after the heater core but when the heater valve is closed, no flow. 
This is the setup I discussed with you when I had the overheating issue winter of 2012-13. It's been bomber ever since, never any temp spikes no matter what I climb.  I no longer feel there is any reason to add an external cooler with these stable numbers. |
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Syncroincity
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Joined: April 15, 2007
Posts: 1557
Location: New York City
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| Posted: Wed Aug 13, 2014 6:15 pm Post subject: |
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My brain hurts. Can someone sketch a diagram of the new layout? I could really use some extra oil cooling. I saw a 240-deg spike on a long uphill stretch of 87 last weekend, even with my front-mount oil cooler setup.
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'86 Syncro CHC Top AAZ Turbodiesel
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
Location: Where?
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| Posted: Wed Aug 13, 2014 7:36 pm Post subject: |
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| Waldi wrote: |
| I hope i understand u right, but if u connect the oilcooler in series with the heater, it works only if the heater is on. |
Yes, that wouldn't work as well as I was thinking... 
| westyventures wrote: |
| I wasn't thinking clearly when I wrote that. The 'top' port of the water pump goes to the head output flange via the J-pipe. |
I wasn't thinking very clearly when I responded either... Yes, bypass to top, heater to center. Anyway, glad to hear that flow path is working for you. |
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Waldi
Samba Member
Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Thu Aug 14, 2014 4:17 am Post subject: |
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| Syncroincity wrote: |
| My brain hurts. Can someone sketch a diagram of the new layout? I could really use some extra oil cooling. I saw a 240-deg spike on a long uphill stretch of 87 last weekend, even with my front-mount oil cooler setup. |
How old is ur water radiator ? |
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denwood
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Joined: July 29, 2012
Posts: 1047
Location: Thunder Bay, Ontario, Canada
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| Posted: Thu Aug 14, 2014 7:10 am Post subject: |
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| Syncroincity wrote: |
| My brain hurts. Can someone sketch a diagram of the new layout? I could really use some extra oil cooling. I saw a 240-deg spike on a long uphill stretch of 87 last weekend, even with my front-mount oil cooler setup. |
115C is nothing to be concerned about as a max during a hill climb, particularly with synthetic oil. Karl mentions 240F/115C as his max with larger coolant/oil solution. I'm seeing similar when towing an 18ft Hobie cat on a 90F day. This is running 5w30 synthetic..and the factory coolant/oil assembly has been removed. My external air/oil cooler is housed in the area behind the passenger rear wheel. Cool air via d-pillar, and exhaust air vented via low pressure at rear of van...just over tail pipe.
Karl, I get the larger coolant/oil cooler, however my motivations were more to eliminate any possibility of coolant/oil mixing during a failure (replaced auto trans cooler as well with FAS unit), and also to reduce heat loading in the engine bay. There is a noticeable reduction in radiator fan cycling. It only ever comes on now if the van is left idling after a highway run.
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hans j
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Joined: May 06, 2006
Posts: 2715
Location: Salt Lake City UT
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| Posted: Thu Aug 14, 2014 7:50 am Post subject: |
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| denwood wrote: |
Karl, I get the larger coolant/oil cooler, however my motivations were more to eliminate any possibility of coolant/oil mixing during a failure (replaced auto trans cooler as well with FAS unit), and also to reduce heat loading in the engine bay. There is a noticeable reduction in radiator fan cycling. It only ever comes on now if the van is left idling after a highway run. |
The oil cooler failures were much more common on the earlier cars. Since I've been working on the modern cars since 2002, I haven't seen a single oil cooler failure where it mixed oil with coolant. The only thing I see is slight leaking at the hoses or one that leaked coolant externally where the aluminum pipes went in to the cooler.
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denwood
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Joined: July 29, 2012
Posts: 1047
Location: Thunder Bay, Ontario, Canada
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| Posted: Thu Aug 14, 2014 8:13 am Post subject: |
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I'm sure age and old coolant (not flushed at regular service intervals) has everything to do with the failures. That said, I still would have removed the OEM coolers on the KISS principle (if adding external coolers).
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westyventures
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Joined: December 29, 2004
Posts: 2306
Location: Oregon Outback
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| Posted: Thu Aug 14, 2014 8:13 am Post subject: |
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| denwood wrote: |
115C is nothing to be concerned about as a max during a hill climb, particularly with synthetic oil. Karl mentions 240F/115C as his max with larger coolant/oil solution. I'm seeing similar when towing an 18ft Hobie cat on a 90F day. This is running 5w30 synthetic..and the factory coolant/oil assembly has been removed. My external air/oil cooler is housed in the area behind the passenger rear wheel. Cool air via d-pillar, and exhaust air vented via low pressure at rear of van...just over tail pipe.
Karl, I get the larger coolant/oil cooler, however my motivations were more to eliminate any possibility of coolant/oil mixing during a failure (replaced auto trans cooler as well with FAS unit), and also to reduce heat loading in the engine bay. There is a noticeable reduction in radiator fan cycling. It only ever comes on now if the van is left idling after a highway run. |
I've never seen a failure in any of mine or customer cars or vans. The V6 unit seems very robust. The 115C was at the end of a very long slog at altitude, one requiring third gear for about 15 minutes, and fully loaded at 5850 lbs, kayak and 16c.f. roof box. The coolant temp rises with this to just under 100 and that's the only time I hear the rad. fan. Normally, shorter or less extreme climbs the oil temp stays at 100-105. The air velocity when needed most in an air/oil cooler is not as good, unless the oil radiator is in high-pressure air; coolant takes away a lot of heat if/when the cooling system isn't already being overtaxed.
Another thing I take into consideration when going this route is the [aux. shaft driven] oil pump is already doing everything it can to maintain good oil pressure, adding another external loop and cooler adds more burden. |
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Waldi
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Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Thu Aug 14, 2014 8:59 am Post subject: |
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The best way to connect the original oil-water-cooler (when using external oilcooler) is to connect the out pipe from cooler to the out pipe from the heater. Near to the plastik deposit is a plastik connector which connects the 2 gomme tubes. Put there a the original T-connector which is used for the internal back heater, and connect there the out pipe of oil-water-cooler.
Together with mine shown pics (first mocal, than water-oil-cooler) u have the perfect solution for heating the oil with water-oil-cooler and cooling the oil with external oil-cooler.
Also there is a difference with oil temp between TDI and "precamera" engines like JX, AAZ. The TDI runs much cooler than the others.
Edit: i had one broken water-oil-cooler in my car, mixing oil with water.
The reason was/is when the cooler is very old the aluminum beginns to rust (corrosion). So i put always a new one when i do a new engine. |
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MsTaboo
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Joined: June 02, 2006
Posts: 4098
Location: East Kootenay, British Columbia
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| Posted: Fri Aug 15, 2014 2:56 pm Post subject: |
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| westyventures wrote: |
I did a mod to the stock layout that really works well:
Ditch the stock smaller water/oil cooler and replace with the Touareg/Audi V6 cooler that is not only larger but has better internal cooling fin layout. |
I would like to give this larger cooler a try, if nothing else it has to work better than the stock one! Is there a part number?
Also, I would like to run this idea by you guys. My passenger heating system is very hot. I'm wondering if a flow restrictor in the passenger heating system supply hose that leaves the head would force more coolant to leave the engine via the main coolant hose to the radiator. Something like this: http://www.ebay.com/itm/Ford-Heater-Core-inline-Coolant-Flow-Restrictor-Mustang-/350478518357
It might help to even out the coolant flow, less to the passenger heating system (which is too hot, and with the heaters shut off this heat just gets dumped right back into the engine) and more to the radiator.
My problem is there is just too much heat in the engine compartment and not enough is making it to the radiator. The Vanagon cooling system has plenty of capacity, there just seems to be a flow problem.
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westyventures
Samba Member
Joined: December 29, 2004
Posts: 2306
Location: Oregon Outback
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| Posted: Fri Aug 15, 2014 3:06 pm Post subject: |
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| MsTaboo wrote: |
I would like to give this larger cooler a try, if nothing else it has to work better than the stock one! Is there a part number?
Also, I would like to run this idea by you guys. My passenger heating system is very hot. I'm wondering if a flow restrictor in the passenger heating system supply hose that leaves the head would force more coolant to leave the engine via the main coolant hose to the radiator. Something like this: http://www.ebay.com/itm/Ford-Heater-Core-inline-Coolant-Flow-Restrictor-Mustang-/350478518357
It might help to even out the coolant flow, less to the passenger heating system (which is too hot) and more to the radiator.
My problem is there is just too much heat in the engine compartment and not enough is making it to the radiator. The Vanagon cooling system has plenty of capacity, there just seems to be a flow problem. |
027117021E cooler
028115721B tube
Have you replaced the thermostat? I use an 80C one. New radiator if the original is still in place? |
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MsTaboo
Samba Member
Joined: June 02, 2006
Posts: 4098
Location: East Kootenay, British Columbia
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| Posted: Fri Aug 15, 2014 3:17 pm Post subject: |
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| westyventures wrote: |
| MsTaboo wrote: |
I would like to give this larger cooler a try, if nothing else it has to work better than the stock one! Is there a part number?
Also, I would like to run this idea by you guys. My passenger heating system is very hot. I'm wondering if a flow restrictor in the passenger heating system supply hose that leaves the head would force more coolant to leave the engine via the main coolant hose to the radiator. Something like this: http://www.ebay.com/itm/Ford-Heater-Core-inline-Coolant-Flow-Restrictor-Mustang-/350478518357
It might help to even out the coolant flow, less to the passenger heating system (which is too hot) and more to the radiator.
My problem is there is just too much heat in the engine compartment and not enough is making it to the radiator. The Vanagon cooling system has plenty of capacity, there just seems to be a flow problem. |
027117021E cooler
028115721B tube
Have you replaced the thermostat? I use an 80C one. New radiator if the original is still in place? |
Thanks for the part numbers.
My cooling system has been completely gone through: New radiator, new 87* tested thermostat, (I'm getting an 80* one), new water pump, new lower temp rad fan switch and new hoses where needed.
I'm hoping the new 80* thermostat will help level out any erratic swings in the opening/closing of the thermostat like Christopher talks about in his post-
http://www.thesamba.com/vw/forum/viewtopic.php?t=538069&highlight=water+pump
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westyventures
Samba Member
Joined: December 29, 2004
Posts: 2306
Location: Oregon Outback
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| Posted: Fri Aug 15, 2014 4:26 pm Post subject: |
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| Water pump with cast impeller? The stamped steel impeller pumps don't work well in our application. |
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outwesty
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Joined: June 06, 2006
Posts: 1074
Location: Tahoe City
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| Posted: Fri Aug 15, 2014 4:44 pm Post subject: |
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Karls idea does work and it is how a stock TDI motor in a car is plumbed. I also had good luck with adding a restrictor into the bypass line going back into the tank. Nothing is welded yet in this pick but this is how I have it routed. I have a mocal 200 sandwich plate with a small 5x10 oil cooler but I may remove it after doing these two mods.
On a trip to MT this past winter doing 75 most of the time my oil temp was at 260 + I stopped....Grabbed a brass plumbing end cap. drilled a 1/4" hole in it and voila....never went over 230-240 deg the rest of the trip. I can still hit 260 but have to really push it...ie staying in 4th at 65 over Donner pass. In normal driving I am just a little over 210 or so.
And before anyone asks. The lift pump in my fuel line is not needed but it sure is nice if you ever run out of fuel or have to open up the system and get it bled again.
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MsTaboo
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Joined: June 02, 2006
Posts: 4098
Location: East Kootenay, British Columbia
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| Posted: Fri Aug 15, 2014 5:15 pm Post subject: |
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| westyventures wrote: |
| Water pump with cast impeller? The stamped steel impeller pumps don't work well in our application. |
The water pump I installed was a Saleri, yes it has the stamped impeller (overall it was better made than the Meyle pump that was available)((pic's in my Gallery)).
However, the pump I had before had a cast impeller and changing the water pump made no difference.
Why should the different type of impeller make a difference?
Outwesty- the stock hose already has a restrictor in that line.
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