What to cool to reduce 1.9 AAZ temps on VW van - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• What to cool to reduce 1.9 AAZ temps on VW van by Gizmoman on 03 Oct, 2011 06:26
• I just returned from a trip crawling up through Yosemite from the 395 (lots of long, steep grades and warm ambient temps) and have a few questions;
  My 82 Westy diesel has a 1.9 AAZ turbo engine running up to 15 lbs of boost, no inter-cooler, stock oil cooler. The transmission is a gasser 09 and I am running oversize tires to keep the revs down. On the freeway it runs at 10 PSI boost most of the time - 65 mph around 3K. The temp gauge reads just a hair over center (covers the right half of the warning light).
  On some of the long climbs, the needle would go up to almost 3/5th's position and really freaked me out a few times. As soon as I headed down hill, it cooled right off. I did this several times on the trip. I kept my foot out of it to hold the boost under 12 pounds during the climbs.
  
  ? Does anyone know what this gauge position is in degrees F?
  I will be putting in a real temp gauge at some point but I would like to know before I hurt this motor.
  Maybe someone here has both real and stock gauges and can give me some ideas of temp VS needle position?
  
  ? If I were to add a cooler - inter-cooler (water to air) or an external cooler, which one would net the most gain?
  
  Any comments appreciated.
  Thanks,
  JW
• #1 by nathan_b on 03 Oct, 2011 07:03
• intercooling can help, but check your rad cap to see if it is holding pressure.
  
  Also, all your pipes and such under the 'gon in good shape? adding an electric water pump may be beneficial with long piping, because that is, essentially, why the temp builds up.
• #2 by Luckypabst on 03 Oct, 2011 07:30
• External oil cooler. I drove that stretch of 395 quite regularly in my 1.6 TD van... Sherwin grade had to be driven by pyrometer rather than speedometer. Oil temps go through the roof under sustained boost of much more than 10 - 12 psi and the stock system just dumps that heat into the coolant. I replaced the stock oil cooler with a thermostatic sandwich plate and an approximately 9"x11" fan-cooled heat exchanger and rarely saw oil temps more than about 20 degrees over target coolant temp.
  
  Chris
• #3 by mystery3 on 03 Oct, 2011 16:11
• I'm not super familiar with vans but I imagine with some creativity you could install a larger core radiator which would give you more efficient cooling and more capacity as well as an oil cooler and/or intercooler.
  
  Are there different water pumps for the aaz that can easily be fitted for better flow?
• #4 by Gizmoman on 03 Oct, 2011 16:44
• Thanks everyone for the feedback. The radiator is in good shape as far as I can tell. Is there some way to know if it is in need of repair? The fins look clear. I suppose I could take it to a radiator shop and have them go through it just for peace-of-mind.
  
  I agree that an oil cooler would be the best way to go. An air to water cooler would possibly help the boost a bit but probably won't do much to lower temps in general.
  As for the possible faulty radiator cap, the system has never needed water so I would think that is all OK. Wouldn't a bad cap make for an overfill on the overflow tank?
  I'm considering putting the fan/cooler in the passenger side pillar in the rear to reduce the plumbing lengths. Do you think this will impede the fresh airflow too much?
  
  I really would feel better if the temp needle would stay in the middle. Every engine I can think of has an "optimum" temp and running over or under is less than ideal.
  
  Thanks again.
  JW
  
• #5 by Gizmoman on 03 Oct, 2011 17:16
• Quote from: nathan_b on 03 Oct, 2011 07:03

  intercooling can help, but check your rad cap to see if it is holding pressure.
  
  Also, all your pipes and such under the 'gon in good shape? adding an electric water pump may be beneficial with long piping, because that is, essentially, why the temp builds up.
  

  Interesting concepts - My guess is that the pipes are original as they have undercoating on them. Is there much chance that the pipes have "arterial build up" like mine do (I am quite old as well) 
  I have noticed that the radiator fan comes on often - even when the temp gauge is in the center. My guess is that the fan temp switch is on the radiator and the gauge temp is reading the engine temp. That makes your pump idea plausible as the water in the radiator is hotter than the gauge is showing - which also means the water in the system is not being transferred very well with the stock pump.
  
  What electric pump do you suggest and where should I plumb it in?
  
  JW
• #6 by CRSMP5 on 03 Oct, 2011 19:57
• its heat soaking the head.. real oil cooler.. intercooler too.. my 1.6td in my b3 wagon does this on large/long hills.. i also have a temp sensor in the pump.. which stays normal... but yes the head gets pretty warm...
  
  you need to add a pyro meter to it..
  
  on my toaster (tdi-m).. when i am running 1250 for long periods.. say tripple mph digits.. long grade.. by the top the heat soak will affect the water temp and move it up... but oil temp still 100c.. up from its normal 90c.. so its due to the turbine temps.. not oil/water per say..
• #7 by RadoTD on 03 Oct, 2011 21:58
• Along with everything stated above, I'd do a good coolant flush too.
  Drain everything out, flush it all out with a hose and fill it back up at about 60/40% of water to G11 coolant. G12 has been known to cause leaks in the older stuff but the G11 is very good coolant.
• #8 by Luckypabst on 03 Oct, 2011 23:32
• Has the radiator ever been gone through? The copper radiator stock to the '82 vans is superior to the later aluminum radiators, but after 30 years, they need to be addressed.
  
  Chris
• #9 by Gizmoman on 04 Oct, 2011 06:23
• All good tips and I appreciate the feedback,
  Is there some way of knowing if the radiator needs rodding out or not? I'm not lazy or cheap, just have a lot of other stuff gong on as well.
  
  The PO was fairly meticulous and I doubt he would have put all the work into this van and left a cruddy radiator in there - it is possible, just not likely. I bought the van last year and the thing is in fantastic shape. The guy did a great job on the swap and also installed a bio system complete with fuel heater and a huge custom aluminum tank for the bio diesel. He also added a small extra radiator with no fan. It sits behind the passenger side rear tire, tucked up high and inside. Obviously he was having difficulties with heat build-up as well. It seems odd he would do all that and not touch the stock core.
  
  The water is clean and light green so my guess is that the mix ratio is pretty close to ideal.
  
  Any feedback on installing the oil cooler in the passenger side rear pillar?
  
  What about thoughts on the intercooler type - Water or air? Currently the intake is nice and short and gets air through a K&N sitting inside the drivers side rear pillar.
  
  I will do some research on how to check for a coked-up radiator. If any one has some ideas, that would be helpful.
  
  Thanks much!
  
  
  
  
• #10 by Luckypabst on 04 Oct, 2011 08:04
• My only thought, short of pulling the radiator, is to use an infrared thermometer to scan the radiator for temperature inconsistencies.
  
  My van needed an electric fan for the oil cooler to work effectively. I think I killed any natural air flow through the rear pillar by opening a hole in the bottom, behind the rear tire. I recall others that have run the oil cooler all the way to the front of the van and claim success, as well.
  
  Chris
• #11 by DieselBalz on 04 Oct, 2011 09:20
• Living in Florida, temps are an issue. A simple 15dollar solution is some Purple Ice, by Royal Purple. Lowered my factory gauge readings by half a tic in all situations. Example, a/c on doin 75 on the interstate, instead of half way between half way and 3/4, it runs on the halfway mark.
  
  An intercooler has been procured and will help.
• #12 by tdihuntdawg on 07 Oct, 2011 20:42
• hello, I also have a 82 diesel vanagon which I installed a Aaz with stock cooling system it was extremely mariginal. in hot weather,i had to install gauges as the dash was trashed I repaired that and now use the stock gauge for oil temp. if you want to keep the stock oil heater/cooler search libbybapa theard for rerouting of hoses so the heater/cooler is only active when thermostat is closed. this helps quick warm-up but prevents overheating of the coolant by the oil. this and the small size and low flow tubes and radiator of the 82 don't allow the heat to leave the engine. the 83 and the gassers have larger tubes. for less resistance of flow.if you double the size you get 4 times the flow so a small increase makes a big difference. I built my own tubes and installed the newer radiator.even with the ac condenser adding heat  my temps are reasonable
• #13 by vixentd on 08 Oct, 2011 00:40
• Having struggled with this problem in a 1993 Passat after putting in a new crate motor the temperature rose about 10 degrees at least.  Tried everything, including sensors, voltage stabilizers in dash etc. 
  
  The cause was the water pump. It had the molded blades that were cast brass almost. When the pump started to leak picked up a new pump and the blades were just stamped tin curled up.  Asked the vw parts guy that I wanted a waterpump that had the molded blades as I assumed it was more expensive and better. He said that was the only type they now had. Installed the cheap looking pump with the bent tin style impellors and temp dropped down signigicantly.  Shared this with several others in Canada and they have done the same change.
  
  The difference is the cheaper style impellor works better by reducing water cavitation.  Might be worth a try to pull the water pump and check what type of impellor you have.  You can probably see by looking in the hose hole also.
  
  Best of luck
• #14 by Gizmoman on 09 Oct, 2011 14:35
• Quote

  I built my own tubes and installed the newer radiator.

  What did you make the new tubes out of and what size are they?
  
  Thanks for the feedback
  
  Jim