FWIW, not my personal experience, but a friend has a 1.9 TD in his westy and was having hot oil issues. He swapped in the super monster oil to coolant "oil cooler", the one thats way bigger than the V6 oil cooler, his oil temps remained mostly unchanged. Hes looking at oil to air coolers now.
I've seen more Vanagon conversion plumbed wrong than right.
"Wrong" being done as stock? And "right" be plumbed different than stock? Or is the stock plumbing correct? I'm not sure how his is set-up...
Jack's talking about my rig. AAZ Westy, Giles injection pump, water-cooled intercooler, and a succession of different turbos & different oil cooler techniques.
I'll give you some benchmark numbers. Note that they are taken under a pretty hard load, 70 - 75 mph with a 1000 lb boat trailer. Usually on relatively level ground near sea level.
Here's a photo of the oil/water coolers that I will talk about, hosted in the thread at TDi club:
http://forums.tdiclub.com/showthread.php?p=742791My old cooler is the one on the far left, stock on the AAZ, probably stock on the 1.6TD and the wasserboxer petrol Vangon engine, too.
My new cooler is the giant on the far right of that photo. I took the part number from that thread.
Plumbing it was pretty idiot proof, just required a couple of odd shaped heater hose pieces to accomodate the different locations for the coolant flanges. Didn't change anything from the stock flow circuit of the original oil/water cooler. I had a machine shop cut me a longer spike from pipe stock and cut threads on it to mount the new cooler & oil filter together.
First Effort Results[/u]
I installed this big oil/water cooler at a time when I was running the ridiculous small K03 turbo. Oil temps would be at 230 F cruising at 70 mph, and easily hit 250 F when goosing it on a fairly limited incline.
I was not especially impressed with the new cooler's effect on oil temperature. Relatively little change, but I blew up the K03 too soon after changing coolers to give you benchmark numbers.
By itself, I expect this mod would probably be similar in effect to Andrew's idea of stacking two stock oil/water coolers. Disappointing results.
Second Effort Results[/u]
Next big mod was to go with a T3 turbo from a mercedes, 0.48 A/R. A giant turbo relative to the K03.
Two radical effects from this change - (1) oil temps were WAY down, such that I could not hit over 230 no matter how abusively I drove; and (2) the thing was awful at spooling, taking forever and never exceeding 10 psi. So annoying that I really had to get a smaller turbo despite the reprieve from hot oil temps that this monster gave me.
Third Effort Results[/u]
So, on to turbo number 3 in 2.5 years, this time a T3 from a 1.6TD engine, A/R 0.36 I think. Now I had something that spooled fairly fast and gave me about 17 - 18 psi boost. However, I was back up to 250 F with the oil, and not happy. Oil temps back up to about where I was at with the K03 turbo.
NB Karl - EGT was cooler than with the K03, but oil temps were the same. This is the chronic story for people with IDI engines in Vanagons - oil temp will get dangerous LONG before EGT or water temps. I would easily hit 250 F on oil temps with only a 900 - 1000 F EGT. There is plenty of anecdotal evidence to this effect from many people. It's typical IDI - Vangon behaviour. There is even evidence to this effect from various independent posts in your Diesel Vanagon Yahoo list pissing match thread.Fourth Effort Results[/u]
Next mod was to delete the oil/water cooler, buy a sandwich plate and tube/fin air-oil cooler to mount in its place. These things should really be front mounted by the radiator, but that's not realistic on a rear-engined Vanagon. I mounted this thing up over top of the transmission on the Van, in a hollow "box" that houses the fuel tank on 4wd Vanagon Syncros. For you Golf/Jetta guys, look at the photo here:
http://www.thesamba.com/vw/forum/viewtopic.php?p=2708095 Pretty lame place for airflow, even with the electric fan. That area of the Vanagon is basically a heat sink, a box up there over the transmission, collecting all the heat from the trans and the tube & fin cooler, with no exhaust or fresh air exchange.
So, off to the highway I go like this, and I hit 265 F on easy inclines (70 mph with 1000 lb trailer remember). Holy crap, that didn't work at all! So for all you guys who say the oil/water coolers do nothing but warm the oil... well, there's proof positive they do *something* to cool the oil.
Fifth Effort Results[/u]
Now I'm up to the final iteration - put the giant PD Passat oil/water cooler back in, but kept the sandwich plate and the tube & fin cooler. Ran around for an experiment this way, with both types of cooler mounted in parallel, but I was really choked to see that I was no better off than the First Effort Results. It was much better than the disasterous Fourth Effort, though.
Then, my eureka moment, I grabbed a section of 4" dryer ducting (coil spring tinfoil stuff), and jammed it into an S shape under the rear trailing arm of the suspension, zipped tying it so it gave me proper ram-air effect on the tube & fin cooler. It hangs lower than any point under the van and does a great job directing fresh ambient air to the tube & fin cooler.
Off I go for a test drive, really romp on it, and I can't get over 225 F oil temps. Eureka. Now for the acid test.
Took the 1000 lb trailer and fully loaded van up a notorious highway system in British Columbia, from Vancouver to Lake Okanagan, in 93 F ambient air temps. Dig the topograpy profile:
That treasure is followed by this one:
I saw over a dozen vehicles dead by the side of the highway that day. 93 F is ugly high heat for that kind of climb, unless your car is in excellent running condition.
I drove a little slower than usual, about 62 - 65 mph.
Oil temps stayed rock steady at 225 F until the steepest sections, at which point they climbed slowly to about 240 F. I backed off at that point, got down into 3rd gear and held 45 - 50 mph. Rocked past the dead vehicles and semis in the crawl lane. Had to get into 2nd gear for the last mile or so before Coquihalla Summit (just North of the avalanche tunnel, if you know this highway), but still could hold 30 mph and under 240 F oil temps.
On the way back home, ambient air was only 83 F, and again I had no trouble holding 225 F for most of the trip. Although the long climb back from Lake Okanagan to Pennask Summit had me in 3rd gear at 50 mph and 240 F for almost all of it. Acceptable results, I thought. If I could have ditched the trailer, I bet I could have kept the oil temps down enough to hold 60 + mph in 4th gear.
So there's my dissertation on the subject. I'm very pleased with the oil/water and tube & fin coolers both working in parallel, as long as the tube & fin cooler has enough fresh air flow. The dryer ducting is ghetto as hell to look at, but really effective. Just have to make sure it doesn't chafe the brake line on that trailing arm.
Once more for Karl - oil temps rocket up disproportionately to EGT or water temps in IDI-powered Vanagons. It's a fact. I never really even had to watch my EGT gauge before, because I had to ***-foot around the oil temps so much that I never even got into sustained boost of the sort that could bring high EGTs.
