Hard Start / No Start - Is your intercooler frozen? Check Here!

[El Dobro]

Winter fronts have only been available for MKIV cars. And they're all gone, obseleted by VW. We got our last two for the Golf last week, no more Jetta.

There was a dealer in Canada that had winter fronts for the Mk5, but I don't think he has them anymore.
I believe it was this place.
http://www.southgate-vw.ca/Service/AboutParts.aspx?lng=2

 

[Big_Tb17]

There is less air going through a TDI intake (intercooler included) than a gasser intake. Our cars get better mileage because they get more 'bang' for the amount of fuel and air. At highway speed, our TDI's will be turning 2000rpm. A similar 2.0T gasser will be higher, say 3000rpm. With the same displacement (and boost), the gasser will be flowing 50% more air.

How it's throttled is a separate matter.

Actually, how it's throttled is everything in this situation.

In a gasoline engine car, your right foot is directly controlling the amount of air that is being allowed into the engine. The RPM is being controlled by the amount of air being allowed through the engine. The engine computer simpy provides a metered amount of fuel based on how much air the throttle is allowing through.

At idle the intake is mostly closed and very little air is allowed into the engine. On the highway in your scenario you would likely be a relatively light throttle, maybe 1/4 or so. That means that the intake was only 1/4 of the way open, so only 1/4 or so as much air as possible would be flowing through the engine.

On a diesel engine your right foot controlls the amount of fuel going into the engine. The amount of fuel going into the engine controls the RPM. The intake is wide open at all times, so the maximum amount of air possible is always being pumped through the engine at any given RPM in a diesel, even at idle.

The only time the gas engine's intake is wide open is when the driver is giving full throttle. So, unless you are going full throttle on the highway at 3,000 RPM, the gasser would not be drawing 50% more air through the engine. It would most likely be drawing less air than the diesel, because it's probably at relatively light throttle to maintain speed, meaning the intake is probably 60-80% closed. Meanwhile, the diesel intake is wide open, as always, so it's engine is pumping the maximum amount of air it can.

Obviously at light throttle the turbo won't be spooled up, so you will get some air increase during higher loads in a turbo diesel, but the same is true of a turbo gasoline engine.

 

[bdisco]

It 20F outside. I have a cold. And I don't feel like plugging in the Salamander to heat up the garage and crawl under my new car. I let you guys figure out how to fix this, I'm gonna go play GT5 on my PS3.

 

[ChippedNotBroken]

Yep, #5 on the passenger side is where the goop accumulates. The hose on the driver's side where it attaches to the intercooler is where the oil usually drips.

That would jive with my theory that there is dead space in the intercooler itself that is causing the problem. It would then "leak" out exactly where you are describing. Just a guess, but I bet $5 that you could swap that intercooler out for a better design and no more problemo.

 

[IFRCFI]

but I bet $5 that you could swap that intercooler out for a better design and no more problemo.

Which means VW would never do it unless forced to. The cost of this times the number of TDIs on the road = never going to spend the money.

This will go unresolved by VW. Mark my words.

 

[53 willys]

I hesitate to respond to the sky is falling comments, however, there is a difference between minor quibbles and major design flaws that cause totaling of an engine with no advance warning, or for the car to fail to operate in routine weather conditions. We paid a lot of money for these cars, and it is reasonable at this point in the history of automobile design to have well know issues such as intake icing resolved.
I fail to see how ANYONE with one of these cars should not be EXTREMELY concerned about water damaging their engine due to this issue. If you drive in humid wintry conditions, I can tell you from experience that this problem is real, and happens often. 1 cup or more of water sitting in your intake at startup is a disaster waiting to happen - you can't argue it any other way.
Since the sky is not falling, I guess I will go back to being blissfully stupid about the operation of my car. And I will refrain from posting my concerns or sharing my experience here, I don't want to aggravate anyone by discussing something that isn't a real problem. I'm sure I should be appeased by draining my cooler hoses every chance I get, and happy when my engine grenades in a year or two when its out of warranty because VW's intake was sucking melt-water straight in. After all, I got my warranty period out of the car right? Thats what I paid for after all. No reason I should expect a $25k car to last more than 60k miles.
Going back in the hole I crawled out from - thanks TDICLUB - over and out.

Im on your side bud I agree its a problem and it does piss me off...I am thankful you posted in the mk6 forum I don't really check mk5 section that much....I drive in nasty weather on my commute all the time and just "dealing" with the sludge and trying to ignore it is not the answer..
I will be pulling my IC hose today for a look.
If I find crap in there I will be filing a complaint to vw..the more exposer this gets the better chance vw might try to come up with a fix.

 

[ChippedNotBroken]

I will be pulling my IC hose today for a look.
If I find crap in there I will be filing a complaint to vw..the more exposer this gets the better chance vw might try to come up with a fix.

Mmmmmm, Utah heh? I'd be shocked if you had this issue. While it may get cold there I doubt you see anywhere near the moisture we see here in the NE.

 

[El Dobro]

On a diesel engine your right foot controlls the amount of fuel going into the engine. The amount of fuel going into the engine controls the RPM. The intake is wide open at all times, so the maximum amount of air possible is always being pumped through the engine at any given RPM in a diesel, even at idle.

On the new CR engine, the intake has valves that control the air. They vary the air flow, depending on the engine's needs.

 

[back2vw]

Well I guess this would explain the rough start and hard idle a few mornings ago at about 2 degrees F. Great. My dealer is terrible and my back/neck is in terrible shape so I cannot get under there to drain it right now...

 

[Big_Tb17]

On the new CR engine, the intake has valves that control the air. They vary the air flow, depending on the engine's needs.

Correct me if I'm wrong, but I believe it's used for emission control in conjunction with the EGR system, not for modulation based on engine needs.

On topic, I only have 3,900 miles on my 2010 Golf so far, but I may check my intercooler hoses later today if I get a chance. I'll post the results if I do.

 

[Bob_Fout]

Actually, how it's throttled is everything in this situation.

In a gasoline engine car, your right foot is directly controlling the amount of air that is being allowed into the engine. The RPM is being controlled by the amount of air being allowed through the engine. The engine computer simpy provides a metered amount of fuel based on how much air the throttle is allowing through.

At idle the intake is mostly closed and very little air is allowed into the engine. On the highway in your scenario you would likely be a relatively light throttle, maybe 1/4 or so. That means that the intake was only 1/4 of the way open, so only 1/4 or so as much air as possible would be flowing through the engine.

On a diesel engine your right foot controlls the amount of fuel going into the engine. The amount of fuel going into the engine controls the RPM. The intake is wide open at all times, so the maximum amount of air possible is always being pumped through the engine at any given RPM in a diesel, even at idle.

The only time the gas engine's intake is wide open is when the driver is giving full throttle. So, unless you are going full throttle on the highway at 3,000 RPM, the gasser would not be drawing 50% more air through the engine. It would most likely be drawing less air than the diesel, because it's probably at relatively light throttle to maintain speed, meaning the intake is probably 60-80% closed. Meanwhile, the diesel intake is wide open, as always, so it's engine is pumping the maximum amount of air it can.

Obviously at light throttle the turbo won't be spooled up, so you will get some air increase during higher loads in a turbo diesel, but the same is true of a turbo gasoline engine.

Great post! This is exactly the difference between an air-throttled stoich engine like a gas engine, and a fuel-throttled variable AFR engine like a diesel.

 

[Ski in NC]

On the new CR engine, the intake has valves that control the air. They vary the air flow, depending on the engine's needs.

As I understand it, the valves in the intake plenum close off one of the two intake ports to increase air swirl in the cylinder under some low load conditions. So it probably does not really affect cylinder filling.

 

[IndigoBlueWagon]

So one of you guys with a MKV or VI should get a scan gauge, record IATs in varying conditions, block off half the IC/radiator sandwich, and see if they change. IATs in the summer will run 100+ degrees. If you got them up into that range in winter I bet you wouldn't have any moisture accumulation. And blocking off half the IC should be easy. Sheet of cardboard would do it if you don't mind being a bit ghetto.

 

[tcp_ip_dude]

So one of you guys with a MKV or VI should get a scan gauge, record IATs in varying conditions, block off half the IC/radiator sandwich, and see if they change. IATs in the summer will run 100+ degrees. If you got them up into that range in winter I bet you wouldn't have any moisture accumulation. And blocking off half the IC should be easy. Sheet of cardboard would do it if you don't mind being a bit ghetto.

Unfortunately Scangauge II won't report IAT on a the 09-10 (don't know about 11), at least not that I can get working (just reports null), I even sent mine back to have the firmware upgraded so I could use the XGauge customizations. I tried a whole variety of XGauge codings and still cannot get MAP, IAT. Only temp I've been able to get is Water Temp.

If you know something I don't, I'd love to hear it as I'd really like to have MAP, IAT, EGT and oil temp.

 

[tcp_ip_dude]

Correct me if I'm wrong, but I believe it's used for emission control in conjunction with the EGR system, not for modulation based on engine needs.

As I understand it, the valves in the intake plenum close off one of the two intake ports to increase air swirl in the cylinder under some low load conditions. So it probably does not really affect cylinder filling.

You are absolutely correct, it has very little effect on overall flow volume and is not intended to throttle airflow. It's well detailed and diagrammed in the VW Self Study Guide (page 9, Flap Valve Function), see excerpt below.

Flap Valve Function
During idling and at low engine speeds, the flap valves are closed. This leads to high swirl formation, with results in good mixture formation.
During driving operation, the flap valves are adjusted continuously based on the load and engine speed. Thus for each operating range the optimum air movement is available.

Starting at an engine speed of approximately 3000 rpm, the flap valves are completely open. The increased throughput of air insures good filling of the combustion chamber.

 

[jaberoo]

I experienced this problem last weekend. Some posts on this issue on other TDI forums and/or threads have talked about changing the air flow from the intercooler to the engine using duct tape. Pardon my ignorance but:

A: Do they mean effectively eliminating the turbo? If so, what would that do to engine power?

B: Exactly what is being recommended? How is it done?

 

[GraniteRooster]

I experienced this problem last weekend. Some posts on this issue on other TDI forums and/or threads have talked about changing the air flow from the intercooler to the engine using duct tape. Pardon my ignorance but:

A: Do they mean effectively eliminating the turbo? If so, what would that do to engine power?

B: Exactly what is being recommended? How is it done?

Think NASCAR style - duct tape over the outside of the exterior fins to eliminate cooling airflow past the intercooler. That will allow turbo warmed air to go into the engine without as much temperature drop through the intercooler. Some sort of plate arranged in would work too.

No changes are made to the internal pressuized intake side...

Not sure how many people have done this yet if any on the new CR's... I might do it but don;t have any tools to monitor intake temps before/after. More heat cant be a bad thing...

 

[El Dobro]

Correct me if I'm wrong, but I believe it's used for emission control in conjunction with the EGR system, not for modulation based on engine needs.

When you shut down your engine and hear the noise under the hood for a few seconds, that's the valve that controls the EGR. It's setting itself for the next start-up. That's not the little valves leading to the intake ports.

 

[El Dobro]

Starting at an engine speed of approximately 3000 rpm, the flap valves are completely open. The increased throughput of air insures good filling of the combustion chamber.

And when you aren't doing 3000rpm (which is most of the time) they are either closed, or adjusting to the load.

 

[dzcad90]

"Goop" in the intercooler and intake tract is nothing new for TDIs. This has been reported here since the first 1Z was torn apart.

The PCV vents into the intake tract and this is the source of the oily residue in the intake tract just as it does now. The CR supposedly has some kind of special CCV vent that is supposed to help reduce intake tract fouling, but the vapor still contains oil.

Searching some older posts in the other fourms will reveal the creative solutions that folks came up with to prevent this from happening.

It would seeem to me that there would have to be EXCESSIVELY damp air to cause any significant volume of water to accumulate. I'm talking wet air filter type damp. Every time you run the car the intake tract should be blown dry by both the force and the temperature of the charge air. If the air were that damp, I'd expect there to be frost in the entire intake tract after a good cold soak.

 

[El Dobro]

"Goop" in the intercooler and intake tract is nothing new for TDIs. This has been reported here since the first 1Z was torn apart.

The PCV vents into the intake tract and this is the source of the oily residue in the intake tract just as it does now. The CR supposedly has some kind of special CCV vent that is supposed to help reduce intake tract fouling, but the vapor still contains oil.

Searching some older posts in the other fourms will reveal the creative solutions that folks came up with to prevent this from happening.

It would seeem to me that there would have to be EXCESSIVELY damp air to cause any significant volume of water to accumulate. Every time you run the car the intake tract should be blown dry by both the force and the temperature of the charge air. If the air were that damp, I'd expect there to be frost in the entire intake tract after a good cold soak.

Have you checked yours?

 

[dzcad90]

Have you checked yours?

Not on the CR, but I have on the 1Z and the ALH and both had oil in the intake tract.

 

[GraniteRooster]

It would seeem to me that there would have to be EXCESSIVELY damp air to cause any significant volume of water to accumulate. I'm talking wet air filter type damp. Every time you run the car the intake tract should be blown dry by both the force and the temperature of the charge air. If the air were that damp, I'd expect there to be frost in the entire intake tract after a good cold soak.

Water should not accumulate during normal operation, I believe the intake velocities if you ever get above 2000rpm are simply too high for any sort of puddle to collect, including if you are driving through a rainstorm sucking water through the intake.

I think the subtlety in this case is the following:

Say its 15 degrees F and very humid. Moisture may or may not be precipitating from the air. The intercooler and charge pipe are exposed to 15 degree cooling air flow around the engine.

Steady cruising at 70 mph, you might be 1/4-1/3 throttle, 2000 rpm, and turbo maybe making 6-8 lbs boost, maybe more or less, any one know?

At 8 lbs boost, that little turbo is probably heating the intake charge well past freezing temperatures (32 F), and now you have warm, moist, liquid/vapor entrained in the airflow headed for the intercooler.

The intercooler is 15 degrees, and liquid water condensing on a 15 degree surface will ice. This icing would be greatest at the outlet and cold side pressure pipe The ice can buildup throughout a long drive.

Intake velocities under typical driving are high enough that any water should get blown through, but not sticky goop, or ice coating the walls.

When the car has an opportunity to warm, the ice melts to form a pool in the bottom of the charge air/intercooler system. Then, on startup, your engine cylinders have to immediately deal with whatever degree of icing happened during your last trip(s) since it was last melted out.

I should mention that as written up on my service report -tech had to use a "pick" to reach up into the IC outlet pressure hose and chip out the ice.

 

[dzcad90]

Water should not accumulate during normal operation, I believe the intake velocities if you ever get above 2000rpm are simply too high for any sort of puddle to collect, including if you are driving through a rainstorm sucking water through the intake.

I think the subtlety in this case is the following:

Say its 15 degrees F and very humid. Moisture may or may not be precipitating from the air. The intercooler and charge pipe are exposed to 15 degree cooling air flow around the engine.

Steady cruising at 70 mph, you might be 1/4-1/3 throttle, 2000 rpm, and turbo maybe making 6-8 lbs boost, maybe more or less, any one know?

At 8 lbs boost, that little turbo is probably heating the intake charge well past freezing temperatures (32 F), and now you have warm, moist, liquid/vapor entrained in the airflow headed for the intercooler.

The intercooler is 15 degrees, and liquid water condensing on a 15 degree surface will ice. This icing would be greatest at the outlet and cold side pressure pipe The ice can buildup throughout a long drive.

Intake velocities under typical driving are high engough that any water should get blown through, but not sticky goop, or ice coating the walls.

When the car has an opportunity to warm, the ice melts to form a pool in the bottom of the charge air/intercooler system. Then, on startup, your engine cylinders have to immediately deal with whatever degree of icing happend during your last trip(s) since it was last melted out.

All of the above is assuming that the charge air temperature at the outlet is 15 degrees, which it's not. The intercooler may be surrounded by 15 degree air, however the temperature of the charge air warms up the intercooler as well as the entire intake tract. The air coming out of the intercooler as well as the outlet is not 15 degrees. I'd wager it's much higher than freezing during normal operating conditions.

 

[Bob_Fout]

Rooster,

At 70 MPH on flat ground, on previous TDIs, it's been 1 to 3 PSI, but I don't know if that correlates to the new ones since they are turning less revs.

 

[Bob_Fout]

All of the above is assuming that the charge air temperature at the outlet is 15 degrees, which it's not. The intercooler may be surrounded by 15 degree air, however the temperature of the charge air warms up the intercooler as well as the entire intake tract. The air coming out of the intercooler as well as the outlet is not 15 degrees. I'd wager it's much higher than freezing during normal operating conditions.

Steady state, IATs with the factory VW FMICs should be 5F to 10F above ambient. Under heavy boost it's gonna be much more though.

 

[IndigoBlueWagon]

I've had lots of rotary pump engined TDI intercooler systems apart, and oil vapor is always present (if the CCV is attached) but I've never seen any liquid. And if the car is running properly there shouldn't be more than a few teaspoons of oil in the intercooler. I doubt anyone has seen the kind of goop pictured here come out of a rotary pump TDI unless the car has a problem.

Air intake temps (measured at the MAP I think, correct me if I'm wrong) are very close to ambient on my ALH when it's not under heavy loads. So it's likely that on a 15 degree day at a 70 MPH cruise the intercooler will be at the outside temperature. Certainly below freezing. If the OP drove relatively gently on a 15 degree day I think it's entirely possible to never get the intercooler above freezing.

 

[GraniteRooster]

All of the above is assuming that the charge air temperature at the outlet is 15 degrees, which it's not. The intercooler may be surrounded by 15 degree air, however the temperature of the charge air warms up the intercooler as well as the entire intake tract. The air coming out of the intercooler as well as the outlet is not 15 degrees. I'd wager it's much higher than freezing during normal operating conditions.

I have read other members reports here of intake charge air 10 degrees above ambient in wintry conditions - so in my example the IC outlet would still be 25 degrees, enough to freeze. But if that number is wrong drop ambient temp a little and the same scenario still happens. Air warmed by turbo heads to cold IC below freezing and ices.

My car choked at 14 degrees and falling. When first in LIMP mode the car could hold 70mph on flats in 6th gear, and 60 on hills in 5th. It continued to loose power for the next 30 min then evened out for the next 40 min. In the end it struggled to maintain 65 and then low 60's on flats and big hills was 4th gear 45mph tops

 

[dzcad90]

Ok. I can accept the fact that at 25 degrees the air would be cold enough to freeze water, but at 25 degrees it takes longer for water to freeze than it does at 15, 10, -10 etc. There's also constant airflow through the intercooler and the intake tract, which should be moving air fast enough through the intercooler to prevent any water vapor from sitting on the intercooler long enough to freeze.

I would still say it would take almost unheard of humidity for this to happen. And my $64K question is - Why didn't we see this on the older TDIs?

 

[tcp_ip_dude]

And when you aren't doing 3000rpm (which is most of the time) they are either closed, or adjusting to the load.

They serve only to generate 'swirl' in the combustion chamber for increased mixing of fuel. Review "Flap Valve" section of the VW Document "Self Study Program #826803 2.0 Liter TDI Common Rail BIN5 ULEV Engine" if you doubt me or please cite references to the contrary.