Oil Temps and Climbing Mountains

Currently in the 'high country' of North Carolina. On the way up, the climb from near sea level to my destination 4800' over a 45-50mile span, I hit a record high oil temp, which was a bit higher than I was expecting - 246F with some extended time in the 235+ range, outside temps ranging from 95F to 75F with plenty of humidity.

With steady highway speeds 50+mph, the temp cools down with no issues. Car actually ran great and held the cruise set speeds without any major loss of speed during the climbs, some down shifts but nothing crazy. On the switchbacks, I'd venture to say a tuned dsg would be more accommodating but nothing I need to change, very liveable.

Being from South Florida, I believe the highest I've reached was maybe 225 during a regen and some stop and go traffic. At what point is too hot?

Currently, I have a moderate load and drove what I believe to be conservative during this part of the trip but still hit 246F for temp. Between cargo, my passenger and dog I would say 600lbs-700lbs of added weight to the car ( 2 people, 1 large dog, suits cases and other luggage.)

I believe if I went to do some harder & more spirited driving, I could easily reach the 250F+ temps. Running Liquid Moly 4200 Top Tec 5W30, if that matters.

Daily driving my car on the hills I drive (each day I have a 3k climb in altitude over the course of 8 miles doing about 60) I easily reach about 220-225 if memory recalls correctly.

Will be interesting t see what I hit going up Conway Pass in a few weeks headed to our family camping spot. It’s a bit north of Bishop, CA and it’s a good climb. There is another right outside of Bishop that is worse.


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Mine hits 240-245 on the regular. My drive home is 110*full AC and 80-85 mph. Good synthetic oil should be fine.

When I lived in Utah and was driving a Toyota of that era with an oil temp gauge, the oil would often get close to what was out of range for that car at 275°F. I hope that's some comfort.

ProfBrown said:

Daily driving my car on the hills I drive (each day I have a 3k climb in altitude over the course of 8 miles doing about 60) I easily reach about 220-225 if memory recalls correctly.

Will be interesting t see what I hit going up Conway Pass in a few weeks headed to our family camping spot. It’s a bit north of Bishop, CA and it’s a good climb. There is another right outside of Bishop that is worse.


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I'd imagine with some of the other mountain ranges, there has to be some higher temps seen than my little climb. I'd guess you'll be higher with Conway Pass.

DevilDogDoc said:

Mine hits 240-245 on the regular. My drive home is 110*full AC and 80-85 mph. Good synthetic oil should be fine.

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I'm not too worried but felt that I could definitely bump the numbers I saw up, if it was a heavier load and harder driving.

Mike in Anchorage said:

When I lived in Utah and was driving a Toyota of that era with an oil temp gauge, the oil would often get close to what was out of range for that car at 275°F. I hope that's some comfort.

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Sure, I think with my 02 Vette and some hard driving in this same area I was getting numbers in the 260-270F range. But that's expected since the whole intention of the car in the mountains was to carve and blast around.

With a good synthetic oil, no problem- I've seen up to 340 degree oil temps on aircooled BMW twins with no damage, I just changed the oil every 6000 miles or 100 hours whichever came first.

I'd be more curios of the charged intake air temps were, that W2A inter-cooler can only suck so much heat out, max I've seen is 285F, not sure where the limiters are on intake temps and it where it cuts power. 285 for coolant is crazy hot IMO.

Remember EGTs and slew of other sensors monitored by the ECU will pull power if outside safe limits.

My air-cooled Vanagon on a normal summer day blasting down the highway:



That's about 275 F oil temp... with an engine that only holds about 4 liters... moving a box... through only 4 gears.

While the CR TDIs certainly get their oil cookin' along good, there are even hotter places.

740GLE said:

I'd be more curios of the charged intake air temps were, that W2A inter-cooler can only suck so much heat out, max I've seen is 285F, not sure where the limiters are on intake temps and it where it cuts power. 285 for coolant is crazy hot IMO.

Remember EGTs and slew of other sensors monitored by the ECU will pull power if outside safe limits.

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I'm interested as well. I haven't really looked at too many of the monitoring options. I've used the torque apps for other cars but nothing for this VW.

The coolant stuck in the middle of gauge (normal area), fans/waterpumps were running after shutdown.

I have a fair amount of time in the area remaining and may attempt some intended spirited driving to see if i notice anything and just to see how the car does compared to other cars I've driven in this area.

gearheadgrrrl said:

With a good synthetic oil, no problem-.

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What about with a good Dino oil, like the one VW recommends? I live in the desert, should I be looking at a synthetic oil? I've read a lot of good things about the Castrol Dino which is what I am currently using.

That IS a synthetic oil. All current VAG spec oils are.

(it also says so right on the bottle, FYI)

VW stopped using dino oil in what late 90's, early 00's?

15TDICommuter said:

I'm interested as well. I haven't really looked at too many of the monitoring options. I've used the torque apps for other cars but nothing for this VW.
The coolant stuck in the middle of gauge (normal area), fans/waterpumps were running after shutdown.
I have a fair amount of time in the area remaining and may attempt some intended spirited driving to see if i notice anything and just to see how the car does compared to other cars I've driven in this area.

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Torque with custom PIDs allows you to see all the sensors. The dash gauge is sooo buffered its kinda a joke, I don't think it moves until engine coolant is above 240F. Also the coolant for W2A IC probably isn't factored into it as it's a separate system/radiator.

oilhammer said:

That IS a synthetic oil. All current VAG spec oils are.

(it also says so right on the bottle, FYI)

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That's good to know....I must have looked at it 3 times and didn't see the "full synthetic". So this will be my first vehicle running synthetic.

We will be climbing some mountain passes in Arizona tomorrow, first North of Tucson at Dripping Springs which if I recall is 7%-8%, then the el Capitan pass coming into Globe with 7 miles of 7% and 2 miles of 8%. Then the Salt River Canyon with it's varied grades and curves. All of this will be in desert temperatures till we finally climb out of the canyon heading toward Show Low. I'll make note of oil temps and post back.

bigb said:

We will be climbing some mountain passes in Arizona tomorrow, first North of Tucson at Dripping Springs which if I recall is 7%-8%, then the el Capitan pass coming into Globe with 7 miles of 7% and 2 miles of 8%. Then the Salt River Canyon with it's varied grades and curves. All of this will be in desert temperatures till we finally climb out of the canyon heading toward Show Low. I'll make note of oil temps and post back.

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Sounds like a climb. Interested to see your numbers.

I'll be taking the Cajon Pass, followed by Deadman summit, then followed by Conway Summit and everything in between on my way to a camping location climbing to nearly 12,300 feet on Conway summit. Can't remember if Matterhorn Peak is in there, but it might be... I'll let you know how my oil temps look. I'll be at the end if not a tad over my 10k mile life on my oil as well. Should be a warm one, in the 90s according to weather now. Car should have me, my girl, some bags and maybe a couple coolers? Planning on setting the cruise to between 70-75 for the whole trip, will be interesting to see what my mileage will be on that long of a trip!

ProfBrown said:

I'll be taking the Cajon Pass, followed by Deadman summit, then followed by Conway Summit and everything in between on my way to a camping location climbing to nearly 12,300 feet on Conway summit. Can't remember if Matterhorn Peak is in there, but it might be... I'll let you know how my oil temps look. I'll be at the end if not a tad over my 10k mile life on my oil as well. Should be a warm one, in the 90s according to weather now. Car should have me, my girl, some bags and maybe a couple coolers? Planning on setting the cruise to between 70-75 for the whole trip, will be interesting to see what my mileage will be on that long of a trip!

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Definitely report back.

I think the west coast has a more aggressive climb but the east coast ranges have the humidity nearly all the way to the top, our ranges are half the size of yours as well.

I did about 750 miles and had an average speed of 66mph over the 11 hr 22min ride. The info center showed 49.2mpg - which is likely 45-46mpg hand calculated. Cruise set at 73mph for about 90% of the drive, one fuel stop and 2 potty stops - 3 total stops. On my way home in about a week I'm planning 1 stop for fuel only since I'm loosing my passanger. But will be going downhill for about 90 minutes.

I do a periodic 2500ft climb up to a ski resort, and with my old ALH and my 2015 GSW it is evident the turbo is very hot when done - can smell a real hot smell. I let it idle at least five minutes before shutting off to let it all cool down a bit.

Full report: Ambient temps varied from 95-100. Oil temp reached 250 on the long stretches of 8%, ECT hit 220. AC on or off didn't seem to change anything so we left it on. Speed was 65, dropping to 60 didn't change anything either. Coolant drops quickly after the summit and oil much slower as I expected. On level ground oil averaged 210-225 and coolant averaged 195-200. Delta between ECT and EOT seems to be right around 20 degrees.

One thing I learned like 740GLE stated, the factory temp gauge just sits on 200 no matter what, it never budged even though actual ECT ranged from 194 to 220 during the trip.

Even with the old ALH, the temp gauge never budged from dead center, which always perplexed me. I finally found out that VW programmed it that way, that if the temp was in a twenty degree range, that it would make the gauge read one value, so the operator would not be "disturbed" by normal variations in temps. So even a basic temp gauge is apparently computer controlled.

davidlp said:

Even with the old ALH, the temp gauge never budged from dead center, which always perplexed me. I finally found out that VW programmed it that way, that if the temp was in a twenty degree range, that it would make the gauge read one value, so the operator would not be "disturbed" by normal variations in temps. So even a basic temp gauge is apparently computer controlled.

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Honestly doesn’t surprise me one bit lol. It’s a German car. I had a bmw that had an mpg gauge, conventional thinking would’ve been that it was vacuum controlled. Nope computer. And that was in the late 90s lol!

My truck was the same way. Gauge said 210, actual temp sensors said 200-208. Don’t think honestly that this is much of an odd ball thing. Most cars will change temps all the time, instead of a gauge making all willy nilly they give it a range. Sure everything from commuter cars to big trucks do this. Cruising on the highways at low rpms on any car will make it cool down, or going downhill. Where as idling in traffic when it’s 100 ambient will make it a few degrees hotter.


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ProfBrown said:

Honestly doesn’t surprise me one bit lol. It’s a German car. I had a bmw that had an mpg gauge, conventional thinking would’ve been that it was vacuum controlled. Nope computer. And that was in the late 90s lol!

My truck was the same way. Gauge said 210, actual temp sensors said 200-208. Don’t think honestly that this is much of an odd ball thing. Most cars will change temps all the time, instead of a gauge making all willy nilly they give it a range. Sure everything from commuter cars to big trucks do this. Cruising on the highways at low rpms on any car will make it cool down, or going downhill. Where as idling in traffic when it’s 100 ambient will make it a few degrees hotter.


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I think most all vehicles have "gauges" like that, not really a gauge but a glorified idiot light. Even on the older stuff the "gauges" were stepped and they moved to the next step at a pre-calibrated interval. I agree they don't want the average owner to freak out and be bringing it in for un-necessary warranty service. Same reason you only see the check engine light when there is an emissions related fault which is govt mandated. If the CEL illuminated on every fault the service dept lines would be overloaded.

Finally got a OBD Adapter that allows for Torque to work.

Some more time in the high country today with 4 adults and some items in the trunk area - solid load.

CACT peaked at 322F, oil hit 250F and coolant hit 228F - realtively aggressive climb in elevation and speeds ranging from a tight switch back speed to 35-40mph total distance is roughly 5 miles. Base temps in the valley are 190 coolant, 210ish oil and CACT 240s, once you hit the climb - temps climb quickly.

Also hit a few longer straightaways where it's highway speeds 50+, temps start to climb and CACT is the first to spike in the high 200s.

It's been muggy 80-90F out and I'm driving pretty smoothly without any real overly aggressive driving style.

Boost seems to be off at idle reading 12.7 or something, I need to find the forum on here. It was listed in the thread I downloaded the PIDs from. Max boost clocked in at 34.7 or something so 20lbs? Not sure might need to do my homework on that.

15TDICommuter said:

Finally got a OBD Adapter that allows for Torque to work.
Some more time in the high country today with 4 adults and some items in the trunk area - solid load.
CACT peaked at 322F, oil hit 250F and coolant hit 228F - realtively aggressive climb in elevation and speeds ranging from a tight switch back speed to 35-40mph total distance is roughly 5 miles. Base temps in the valley are 190 coolant, 210ish oil and CACT 240s, once you hit the climb - temps climb quickly.
Also hit a few longer straightaways where it's highway speeds 50+, temps start to climb and CACT is the first to spike in the high 200s.
It's been muggy 80-90F out and I'm driving pretty smoothly without any real overly aggressive driving style.
Boost seems to be off at idle reading 12.7 or something, I need to find the forum on here. It was listed in the thread I downloaded the PIDs from. Max boost clocked in at 34.7 or something so 20lbs? Not sure might need to do my homework on that.

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Mind sharing the PIDs you used for CACT and EOT?

bigb said:

Mind sharing the PIDs you used for CACT and EOT?

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Sure - post #8 in the link. Directions worked for me, like I said boost is off but likely my phone being in a different unit.

http://forums.tdiclub.com/showthread.php?t=391922

15TDICommuter said:

Sure - post #8 in the link. Directions worked for me, like I said boost is off but likely my phone being in a different unit.
http://forums.tdiclub.com/showthread.php?t=391922

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Thanks...I had downloaded that csv a while back and didn't remember, added the gauge tonight

I discovered the other day pulling my long hill at 110 with ac going full blast that the stock gauge moves to the next line off the middle when you hit 230*. I was very pleased that it moves before it overheats. Cooled right down to 215 after I got back on lever ground. Oil temps got to 250 at their highest. I read that the flashpoint for the factory Castrol is around 350 so I think I’m ok

DevilDogDoc said:

I discovered the other day pulling my long hill at 110 with ac going full blast that the stock gauge moves to the next line off the middle when you hit 230*. I was very pleased that it moves before it overheats. Cooled right down to 215 after I got back on lever ground. Oil temps got to 250 at their highest. I read that the flashpoint for the factory Castrol is around 350 so I think I’m ok

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110 as in 110mph? If so, good luck.....


Car stock cools down great. But the same car stock seems to heat up pretty quickly when climbing. Not that it really matters but I will be bringing up my C5Z in the next year on the same roads, it will be interesting to see where the temps land on that car. Likely to be the same but might take some rpms to see the numbers.

15TDICommuter said:

110 as in 110mph? If so, good luck.....
.

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When I read that it registered as 110 degrees but looking again I think you're right, it's 110 MPH. One thing I noticed a lot of guys here have in common with the guys over on the Mercedes diesel forum, they like to go fast.