High elevation, hill climb, high load overheating?

I made a post a while back about my tdi getting slightly hot on my way up skiing. Reached 233* twice on two different sustained climbs.

VW checked everything at my 10k service and said operating normal. They even opened a tech line with corporate and no concerns.

I finally went up again and this time I was more aware and played with sport mode a bit to increase rims in hopes of keeping out of max boost. It seemed to work better as max temps hit 226.

I'm curious if you guys have any advice or imput on the subject. Above 225 the gauge moves. I don't like having to babysit the gas pedal fr fear of damaging or overheating my car.

Keep in mind this is all with just me in the car. Next week my parents are in town and I will be headed back to the mountains. This time loaded up with an additional 500lbs of people/gear. So I'm a little nervous.

Few questions. Does RPMs affect water flow? I assume our water pump is electric so I'm not sure it works the same as belt driven pump.

My EGT temps stayed pretty constant at 700-900 with upper ranges being near max temp for this past trip. Is this damaging the turbo running this warm? I know it's still less than a regen but I don't know if it's heating the turbo differently than during a regen.

Do diesels tolerate high operating temps like that? 233ish? What point do I cause damage or should I be concerned.

Also does being in sport mode really benefit me in terms of keeping it running cooler?

Thanks for the points. My guess is I need to worry less but I think my concerns are somewhat legitimate. It makes me wonder if temps are like this in the teens. What are they going to be. In summer when its 80+

High operating temp should fine - the only thing to be concerned with is the maximum temp the coolant mixture can handle. As long as you aren't in the red on the temp gauge, I wouldn't worry much about it.

Just to CYA, make sure it's on record that you've expressed concern about this to VWoA - in case there's a head gasket failure or something like that in your future.

Keep updating us, though! I'd like to keep following this.

Does the dsg run fluid through the radiator like a typical automatic? Passat's having the air to water IC getting heat soaked? Just ideas.

Have never seen the temp move off of mid point on 2012 Passat TDI SEL. I live at 8500ft and frequently drive above 11,000ft.

I have not seen this in my 2012 either. But I will pay more attention for next time! All my TDI's have been just fine, never overheat. I live in Aurora also.

Chad are your fans running when the engine gets hot?

VeeDubTDI said:

Chad are your fans running when the engine gets hot?

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That's a good point. Check some relays and see if they are kicking on. It is hard to overheat a car with ambient air temps in the teens or lower.

Jayg said:

That's a good point. Check some relays and see if they (the fans) are kicking on. It is hard to overheat a car with ambient air temps in the teens or lower.

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I agree with this suspicion. I'd have it checked out. Previous Jetta TDI and current Passat TDI never budge off of the middle even on long upgrades in the summer carrying capacity-loads. (My experience not at your altitude but at much warmer ambient temps.)

Went up to Keystone with the better half and her parents today.....as far as the temp (dummy) gauge goes, it didn't move. Clear driving up, snow dumping with stop and go traffic til after the tunnel on the way back.

I'm pretty positive the fans are running. I notice them on anytime the EGT is above 500.

Like I said VW looked over the system and I ave them details of what happened. This time was better but gauge still moved slightly once.

I definately plan to raise a fuss if temp goes up again when I head up on Wednesday.

I'm just trying to arm myself with some more knowledge on these cars. My first diesel and really my first turbo car as well.

Up in frisco right now drive up didn't notice any temp bumps

Dang I wonder what could be causing this since other colorado people are not having the issue.

does anyone know about our water pump? is it electric?


I'm headed back up to Breck tomorrow in blizzard like conditions so I'm not sure I will have the speed to get my temps up but we shall see. I will post results.

The water pump is turned by the timing belt. I've never seen an electric water pump in a car.

d2305 said:

The water pump is turned by the timing belt. I've never seen an electric water pump in a car.

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Not sure I've seen a stock electric water pump but aftermarket, they're all over.

The intercooler loop has an electric water pump.

d2305 said:

The water pump is turned by the timing belt. I've never seen an electric water pump in a car.

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ok so the timing belt is spun according to RPM's correct? so faster I rev the more water flow?

yeah "I think" some manufactuer's are starting to use them stock. kind of like electric powersteering pumps are becoming pretty common now.

Yes but faster doesn't necessarily mean more cooling.

VeeDubTDI said:

Yes but faster doesn't necessarily mean more cooling.

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Right, more rpms can mean more heat generated too. I assume your heat is blasting as you are driving up there too right?

Could it be a malfunctioning thermostat? If it is stuck in the open position, it can potentially make the coolant temperature rise if it isn't staying in the radiator long enough to release enough heat.

I traveled between Denver and Rifle on I-70 in July, and my temp gauge didn't move, even maintaining the speed limit on the run up to the Eisenhower Tunnel.

Jayg said:

Right, more rpms can mean more heat generated too. I assume your heat is blasting as you are driving up there too right?

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well my thought and I could be wrong is that higher rpms will flow more water and I'm finding most of my high temps are generated when I am stead at about 2k rpm which I assume is max boost.

if I keep it in sport mode. it shoots the rpms into the upper 2k range and I assume I'm not max boost anymore (no idea) but if I am at least i have better water flow to offset?

I don't think it's a malfuntioning thermostat as I only have had this issue when climbing the rockies

I'm driving up again today at somepoint but there is a "blizzard" here and my parents plane has not left the runway in AZ

ChadS99SVT said:

well my thought and I could be wrong is that higher rpms will flow more water and I'm finding most of my high temps are generated when I am stead at about 2k rpm which I assume is max boost.

if I keep it in sport mode. it shoots the rpms into the upper 2k range and I assume I'm not max boost anymore (no idea) but if I am at least i have better water flow to offset?

I don't think it's a malfuntioning thermostat as I only have had this issue when climbing the rockies

I'm driving up again today at somepoint but there is a "blizzard" here and my parents plane has not left the runway in AZ

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Boost is not tied directly to RPM. You can be at any rpm and not make any boost if you accelerate slowly enough. I wish these cars had a boost gauge stock so you could see how it works.

Even at full boost your aftercooler for the water to air should be fine with that low of ambient temps and snow hitting it.

Assuming you're traveling the same road, 5th gear should run less boost than 6th gear at a steady cruise (example, climbing a mountain @ 70 mph). Your EGTs will also be less in 5th than in 6th.

Jayg said:

Boost is not tied directly to RPM. You can be at any rpm and not make any boost if you accelerate slowly enough. I wish these cars had a boost gauge stock so you could see how it works.

Even at full boost your aftercooler for the water to air should be fine with that low of ambient temps and snow hitting it.

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I'm not a total noob haha.

I'm talking under a load. Basically what Veedub is stating.

Yeah I wish we had a gauge or the scan gauge could pick up on it. Any chance an update of some sort will allow that in the future?

ChadS99SVT said:

I'm not a total noob haha.

I'm talking under a load. Basically what Veedub is stating.

Yeah I wish we had a gauge or the scan gauge could pick up on it. Any chance an update of some sort will allow that in the future?

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Ok I thought you were implying they were linked. For so many people these cars are their first turbo cars and first diesels.

Perhaps in your cause I'd get the bluetooth obd plug and torque app and watch what your boost is doing the next time you go up.

Faster water flow doesn't necessarily equate to more heat removal either. If it is circulating too fast it can't pick up enough heat from the engine as well as lose it at the radiator.

Well made it up to frisco for tonight then staying in Breck the next few nights. Car did fine this time max temp was 224. I still was dropping it into sport mode when temps climbed up though.

It's frigid up here tho weather.com reporting -14 temps. Hope my fuel doesn't gel

I think something is up with your car. It shouldn't be getting that hot when it's that cold outside.

I have a vagcom. We both live in Aurora. Hmmm..... Seems like a plan is forming!

VeeDubTDI said:

I think something is up with your car. It shouldn't be getting that hot when it's that cold outside.

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Yep. 224 is the ragged edge of what your car should be doing when its towing a trailer in 90 degree weather.

jaydhall said:

I have a vagcom. We both live in Aurora. Hmmm..... Seems like a plan is forming!

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Hmmmm what would be able to do. I'm a noob with that stuff.


On a side note it was -14f this morning and car started right up. No crazy sounds either.