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Jon_slider Wed Jun 05, 2013 9:35 am

Preliminary observations of transaxle temperature with my 5cyl TDi powered 87 Syncro Westy.

This morning I drove from Santa Cruz to Davenport and back at 55 mph. It is about a 20 mile loop.

Outside temp was about 55f and my max tranny temp was 140f. My EGT never went over 900f and my water temp gauge never got past 1/4, needle never touched the LED.



Last night I drive from Santa Cruz to Los Gatos and back, over hwy 17, about 20 miles each way.

I set cruise control to 55mph in 4th gear, unless traffic forced me to slow to 45. Max EGT was 1250f, max tranny temp 160, water temp never reached the LED.

I intentionally did not use 3rd gear, I wanted to make as much heat as possible. Rpm was between 2000 and 2400. Outside temp was about 65f.

More testing to follow after longer drives in hotter weather. So far my tranny temp, with no tranny cooler seems very reasonable.

A note about EGT, since my probe is post turbo, I am reporting 250f higher than my gauge shows, to be comparable to EGT probes placed pre turbo on other motors.

dobryan Wed Jun 05, 2013 9:50 am

Just out of curiosity, what is the engine coolant temp at that low analog gauge reading?

crazyvwvanman Wed Jun 05, 2013 9:55 am

Clearly his coolant gauge reading is abnormally low, indicating a problem of some kind.

Mark

dobryan wrote: Just out of curiosity, what is the engine coolant temp at that low analog gauge reading?

lloydy Wed Jun 05, 2013 10:25 am

Not necessarily.... Depends what temp sender is being used. On mine i started with the tdi sender being connected to the dash gauge (it's 4 pin, two to ecu, two to gauge) this showed as my gauge being just under max @ 85 deg on the scangauge. 70 deg was on the led.
So i fitted an extra vanagon sender to the back of the head and wired the gauge to that, 89 deg is now on the led.
So it could just be something like that

MarkWard Wed Jun 05, 2013 10:31 am

Here is a side by side of my stock coolant gauge and the scan gauge. You will notice that the needle is on the bottom of the LED at an indicated 190 FWT. Normal operating temp for the TDI is around 190F. That was on a 90 degree day. On a cool day, I have seen the engine run at highway speeds in the low 180s. Stock Thermostat installed. I believe the vanagon cooling system might be a little oversized for an efficient TDI. There was a thread about closing up the air flow across the radiator in cold climates on diesels. In theory the thermostat should maintain a constant temp regardless of ambient, but I personally have not seen that. Maybe my thermostat is not closing completely.


lloydy Wed Jun 05, 2013 10:40 am

i should have put in deg F, i was using celsius..sorry, but your pic there backs up what im saying. I wasnt happy leaving the stock gauge showing a false reading, which is why i fitted a standard vanagon sender as well as the tdi one. i removed the two wires from the tdi sender that supplied the gauge and fitted them to the vanagon sender which i cut into the heater hose at back of head. Gauge is now spot on and makes me feel more comfortable when i look at it

crazyvwvanman Wed Jun 05, 2013 10:58 am

Yes. Having a mismatched temp sender for a given temp gauge qualifies as a problem of some kind.

Mark

lloydy wrote: Not necessarily.... Depends what temp sender is being used. On mine i started with the tdi sender being connected to the dash gauge (it's 4 pin, two to ecu, two to gauge) this showed as my gauge being just under max @ 85 deg on the scangauge. 70 deg was on the led.
So i fitted an extra vanagon sender to the back of the head and wired the gauge to that, 89 deg is now on the led.
So it could just be something like that

hans j Wed Jun 05, 2013 11:31 am

As far as the temps go, I haven't checked mine much with the diesel swap. I am kind of thinking they might be cooler since the bell housing is further from the engine?

I have noticed however that my shifting is much smoother even in higher (so far) temps since I redid my shift bushings and unfroze the universal joint in the shifter. Last year I was having a gummy trans issue from 4-3 when hot out, and it hasn't been that hot yet this year.

As far as the temp gauge goes, that is definitely low and should reach full temp within 3-4 miles of driving. For my conversion I am using the factory vanagon sender for the cluster and the CTS just for the ECU.

I started the TDI in winter thread and found my thermostat was ultimately bad, even now without the covers and when it's cold out, my temp driving down hill (after fully warm) never drops below 85*C

Do you have any comparison readings on the trans with an infrared temp gun? I don't have a gauge for mine yet. Certain location to check?

gears Wed Jun 05, 2013 11:50 am

I'll throw a caution out there .. Your transaxle oil temperature reading does not tell the whole story. I have yet to see a vanagon temperature reading that would concern me, and yet I know that many of our vanagons are experiencing heat build-up in 4th gear. The effects of this are damaging on 4th gear and the mainshaft ball bearing.

This heat build-up is a serious issue (especially in conversion vans), and is the reason I recommend flipping the manual override switch for the trans oil pump/cooler BEFORE a long uphill climb. DON'T wait for overall oil temperature to activate the system .. at least not on long hills.

I'd also recommend at least a few seconds of running the trans oil pump before even starting the car. The mainshaft ball bearing doesn't see any oil exchange until the pinion shaft begins turning, when 4th gear can deliver a bit of oil to that forward area. Until then, the ball bearing is relying on any residual oil pooled in the cupped bearing race .. not much.
JMHO

r39o Wed Jun 05, 2013 12:25 pm

Pump needed for mild conversions with SA oiling plates?

I tend to agree the measured temp is not the issue.

Pulling up hills at 1600 rpm at 55 in 4th seems like a huge load to me.

rmcd Wed Jun 05, 2013 12:27 pm

Is this transmission heat issue a problem with a manual transmission?

If so will a GoWesty-like automatic transmission cooler kit work on a manual transmission?

Does anyone make a transmission cooler kit for a manual?
Thanks
Rob

Alaric.H Wed Jun 05, 2013 1:58 pm

Jon_slider wrote: Preliminary observations of transaxle temperature with my 5cyl TDi powered 87 Syncro Westy.

This morning I drove from Santa Cruz to Davenport and back at 55 mph. It is about a 20 mile loop.

Outside temp was about 55f and my max tranny temp was 140f. My EGT never went over 900f and my water temp gauge never got past 1/4, needle never touched the LED.

[pics]

Last night I drive from Santa Cruz to Los Gatos and back, over hwy 17, about 20 miles each way.

I set cruise control to 55mph in 4th gear, unless traffic forced me to slow to 45. Max EGT was 1250f, max tranny temp 160, water temp never reached the LED.

I intentionally did not use 3rd gear, I wanted to make as much heat as possible. Rpm was between 2000 and 2400. Outside temp was about 65f.

More testing to follow after longer drives in hotter weather. So far my tranny temp, with no tranny cooler seems very reasonable.

A note about EGT, since my probe is post turbo, I am reporting 250f higher than my gauge shows, to be comparable to EGT probes placed pre turbo on other motors. 55 whole mph 160deg. Try it at 70mph then you will know why you put in a trans cooler.160 is a little hot for 55mph 130-150 is what I am showing. The sender on mine may be in a different place as yours.
My trans temp is the far right gauge bottom the top is the intercooler temp.



gears Wed Jun 05, 2013 2:40 pm

Yep .. huge loads on poor little 4th gear tooth faces in our 4-speed manual transaxles. I'm amazed at how few outright 4th gear failures occur.

I think we're on the right track to greatly increase the longevity of ALL of our transaxles. Alaric's cooler is WAY more effective at combating the problem than the splash plates.

And the way Daryl designed his system (for Jon) is nicer yet, as it directs much of the cooled oil directly on the 4th gear .. MANY times more effective than those SA splash plates.

Both Alika and I were both planning to go the "Full Herman" with gun-drilled shafts and modified pinion bearing race etc .. However, I've come to feel Daryl's version is as far as one needs to go. Draw the heat out of that 4th gear, and mainshaft ball bearing issues go away. (I am however, looking forward to seeing Alika's project. He's already got his shafts gundrilled.)

Oh .. one more thought. I think it's possible to overcool the oil. As some of us have read recently, the EP additives in many gear lubes don't work well at lower temperatures.

Witless Joe Wed Jun 05, 2013 3:01 pm

Alaric, Highway 17 from Santa Cruz is a steep car-killing road.

The 130*-150*F that you generate at 55 mph, is probably a reading taken on a much flatter road than Hwy 17.

Jon_slider Wed Jun 05, 2013 3:52 pm

This afternoon coming back from San Jose to Santa Cruz, I did 15 miles of 70mph freeway before climbing highway 17. Tranny temp was already 160 when I started to climb hwy 17 @55mph in 4th.

By the time I got to the top of 17, Tranny temp was at 190. Next week the cooler gets installed. Temp did not drop below 170, where I have a red light alarm set, until I got to Santa Cruz. It takes a large lag of time and distance (more than 10 miles) for tranny temp to come down.

Here are a couple of shots, when I started building tranny temp going uphill, before I got up to 190F. fwiw, downshifting to 3rd and dropping to 45mph for the last 2 miles of climb did not show any drop in tranny temp over such a short interval.




(add 250f to the EGT you see)


2000rpm is 50mph, you can see my water temp gauge has climbed one needle width


hard to see, but this is just above 170F

My first impression based on these results is that going 70mph on freeway has a much bigger impact on tranny temp than going 55mph on flat ground.

My EGT is the first to climb when Im going uphill, my water temp barely moves, but does climb about one needle width, and tranny temp, climbs with some lag, about 5 miles, behind the actual load presented..

I would think that there are huge temperature spikes in the transaxle gear faces that are not shown by the gear oil temperature, other than to climb higher gradually. Conversely, going down hill, very little load, at 55mph, drops EGT immediately, drops coolant needle in about 2 miles, but takes about 10 miles to bring tranny temp down.

Last night I climbed highway 17, and never saw more than 160F tranny temp, but I started cold after dinner in Los Gatos, so there was no initial freeway at 70mph like today, to preheat the gear oil. I would say it takes at least 10 miles at 70mph to get up to 160f gear oil, after that climbing hwy 17 adds 30 degrees.

I imagine the load last night was just as high as today, the tranny temp just did not have time to average the extreme heat being produced at the gear faces, hence a low tranny temp reading. Bottom line, yes, going 70mph warms things up, and climbing steep hills adds to that.

> The 130*-150*F that you generate at 55 mph, is probably a reading taken on a much flatter road than Hwy 17.

agree completely, the following data was on a flat road
"This morning I drove from Santa Cruz to Davenport and back at 55 mph. It is about a 20 mile loop.
Outside temp was about 55f and my max tranny temp was 140f."

gears, thanks for all your input. I would prefer not to have an operator switched tranny cooling system. The thermostat for the tranny cooler is supposed to trigger at 150F, although Blair reports it seems to actually trigger around 127F based on his scangauge type device reporting his water temp.

Hopefully you agree there is no need to use a manual switch with the thermostat in the system... since the gear oil goes to 140-160f in 55-70mph flat road conditions. By that I mean, the tranny cooler will already be running, before I get to any hills.

Also, gears, I wonder if the EP additives are activated by the extreme heat at the gear faces, even if the average gear oil temperature is not as high?

Alaric.H Wed Jun 05, 2013 4:34 pm

Witless Joe wrote: Alaric, Highway 17 from Santa Cruz is a steep car-killing road.

The 130*-150*F that you generate at 55 mph, is probably a reading taken on a much flatter road than Hwy 17. If you look at the GPS it is reading 72mph with the cruse on and in my opinion highway 17 is a sissy road. These roads here are pretty tough on vanagons as you can not set the cruse control because of all the slow people in front of you.




Jon_slider Wed Jun 05, 2013 4:40 pm

> If you look at the GPS it is reading 72mph

thanks for your input Alaric, sorry I got confused talking about my 140F tranny temp, when youre talking about your 131F coolant temp.

Can I please see a photo of your stock coolant temperature gauge when your gauge pod coolant temp says 131F at 72mph?

are you saying my stock coolant temp gauge needle running below the LED is normal for your 2.5 TDi van also, or not?

Alaric.H Wed Jun 05, 2013 5:02 pm

Jon_slider wrote: > If you look at the GPS it is reading 72mph

thanks for your input Alaric, sorry I got confused talking about my 140F tranny temp, when youre talking about your 131F coolant temp.

Can I please see a photo of your stock coolant temperature gauge when your gauge pod coolant temp says 131F at 72mph?

are you saying my stock coolant temp gauge needle running below the LED is normal for your 2.5 TDi van also, or not? The coolant temp is the one that reads water the trans temp is the one reading 131F far right bottom number.

Jon_slider Wed Jun 05, 2013 5:13 pm

> the trans temp is the one reading 131F far right bottom number.

ok, thanks, you have a very nice low transaxle gear oil temperature.. I take it that is with a tranny cooler running, yes?

I do not have a tranny cooler yet, just a tranny temp gauge..

when your water coolant temp on your gauge pod says 191f, thanks for the picture, what does it look like on your stock coolant temp gauge?

does your stock coolant temp gauge needle sit below the led also? Can I see a picture please, at 70ish on flat ground?

Alaric.H Wed Jun 05, 2013 6:54 pm

Jon_slider wrote: > the trans temp is the one reading 131F far right bottom number.

ok, thanks, you have a very nice low transaxle gear oil temperature.. I take it that is with a tranny cooler running, yes?

I do not have a tranny cooler yet, just a tranny temp gauge..

when your water coolant temp on your gauge pod says 191f, thanks for the picture, what does it look like on your stock coolant temp gauge?

the point of the question is to follow up on crazyvwvanmans comment that my stock coolant temp gauge reads too low because my needle does not touch the LED, and is usually one needle width below it, on flat ground.

does your stock coolant temp gauge needle sit below the led also? Can I see a picture please, at 70ish on flat ground? At the time I did not have a cooler on the first picture. AS far as your needle it is just fine as our motors run much cooler than a WBX. Half way up is about 200-210F on a stock motor.In the winter I drive around with the espar on at slow speeds so I can have some heat. Fan almost never comes on.



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