Coolant leak

I have a coolant leak that shows up in my garage floor from time to time. It is approximately in the middle towards the passenger side. Previously my Passat had the tandem pump coolant leak fixed ($$) about three and half years ago (fuel pump gasket, cooling hose flange & water temperature sensor R&R. Cooling system flush and bleed).

I also hear quite often the sound of the coolant gurgling when I start driving.

Thoughts?

Coolant doesnt go through your tandem pump on your BHW. Oil, air and diesel. They should not mix.
Its common to have oil or diesel leak from your tandem pump and cause the coolant hoses to swell and break that are directly under your tandem pump at the back of your motor.
This is probably where i would start looking.
Are you sure you are hearing coolant or are you hearing the fuel pump kick on when your key is turned to the on position?

Look at the EGR cooler as that is a leaker when these BHW's age. I should know.

The coolant gurgle is trapped air rushing through the heater core. There is a bleed hole in the end of one of the heater core hoses designed to help purge it.

PickleRick said:

Coolant doesnt go through your tandem pump on your BHW. Oil, air and diesel. They should not mix.
Its common to have oil or diesel leak from your tandem pump and cause the coolant hoses to swell and break that are directly under your tandem pump at the back of your motor.
This is probably where i would start looking.
Are you sure you are hearing coolant or are you hearing the fuel pump kick on when your key is turned to the on position?

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Sorry I was not clear enough. I did not mean that my tandem pump had a coolant leak but rather that my previous coolant leak, a few years ago, was due to what you describe (oil or diesel leak from your tandem pump and cause the coolant hoses to swell and break). This issue has already been addresed so this coolant leak is most likely due to something else.

aja8888 said:

Look at the EGR cooler as that is a leaker when these BHW's age. I should know.

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Thanks for the reply. Yes, this is a good possibility in my case. Did you take it to a mechanic to fix it?

JETaah said:

The coolant gurgle is trapped air rushing through the heater core. There is a bleed hole in the end of one of the heater core hoses designed to help purge it.

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Good to know. I guess this will be fixed along with the coolant leak fix that I need to take care of.

Also if the EGR is the culprit, is the there another risk while it gets fixed (probably in the next few weeks)?

tikal said:

Thanks for the reply. Yes, this is a good possibility in my case. Did you take it to a mechanic to fix it?

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I think I had Robbie replace the cooler. But that was several years ago. It's not a big job since the cooler is just above the turbo on the passenger side.

aja8888 said:

I think I had Robbie replace the cooler. But that was several years ago. It's not a big job since the cooler is just above the turbo on the passenger side.

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Good to know that it is not a big job as opposed the one caused by the tandem pump. I will probably will take it to Das Auto (it has a new updated name I think) since it is not worth it to go out of town for this one.

tikal said:

Good to know that it is not a big job as opposed the one caused by the tandem pump. I will probably will take it to Das Auto (it has a new updated name I think) since it is not worth it to go out of town for this one.

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Right, I know Christian who started that business. He used to live in The Woodlands. He has really expanded and is getting pricey! But he is good.

If it was 3.5 years ago it is quite likely the flange is shot again.

I am sure it is possible but I have not seen an EGR cooler leak externally. Just internally to the exhaust.

I would plan on replacing the coolant flange. I would also delete the cooler for good measure. That normally takes care of the gurgle too.

vwztips said:

If it was 3.5 years ago it is quite likely the flange is shot again.

I am sure it is possible but I have not seen an EGR cooler leak externally. Just internally to the exhaust.

I would plan on replacing the coolant flange. I would also delete the cooler for good measure. That normally takes care of the gurgle too.

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Why in such a short time? Because I should have changed the tandem pump also?

EGR coolant leak?

vwztips said:

If it was 3.5 years ago it is quite likely the flange is shot again.
I am sure it is possible but I have not seen an EGR cooler leak externally. Just internally to the exhaust.
I would plan on replacing the coolant flange. I would also delete the cooler for good measure. That normally takes care of the gurgle too.

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At the shop, several weeks ago, they pressurized the system and there was no leak. Since then I have not seen any coolant spots in the garage floor but I need to periodically add coolant so I suspect that is culprit the EGR cooler. In the recent UOA there was no issues of coolant in the oil so I do not think there are any issues for the coolant leaking somewhere internally in the engine.

Regarding the EGR cooler I have some questions:

1) Is there a negative side effect about deleting the EGR cooler? Other options?
2) Do you have the part number for the EGR cooler and coolant flange?

Thanks in advance.

The only negative i can think of is it takes longer for the heat to work in the car. You're in Texas so this shouldn't be an issue.

Secondly, i believe your ecu needs a tweak when this is done so you dont throw a code. Hopefully someone else will chime in and let us both know 100%. My ecu is at a tuners shop as we speak for many other mods and i was asked about the egr delete.

I have ordered the block off plates. Im still not sure if the delete kit comes with the appropriate hose to finish off the delete, ill know in a few days when ups brings all my parts to me

I have never seen a BHW EGR cooler leak externally.

I have seen a few suddenly fail INTERNALLY, and this was causing a bunch of coolant being pushed into the intake and causing the engine to smoke heavily.

The flange at the rear of the head is a common one, I have also seen one that had the hose that comes off of that flange over to the oil cooler fail and leak... this was one that had a fuel leak at the tandem pump previously, and the shop (dealer) that replaced the pump I guess did not notice the mess underneath .

I have also replaced a few of the vent hose assemblies, the part that goes into the head fails.

Seems all the PDs have a tendency to seep some oil at the rear corner of the valve cover and sometimes the tandem pump seal. Some worse than others. Lately I have had good success with new valve covers, as the gasket alone does not always get it sealed back up totally.

oilhammer said:

I have never seen a BHW EGR cooler leak externally.
I have seen a few suddenly fail INTERNALLY, and this was causing a bunch of coolant being pushed into the intake and causing the engine to smoke heavily.
The flange at the rear of the head is a common one, I have also seen one that had the hose that comes off of that flange over to the oil cooler fail and leak... this was one that had a fuel leak at the tandem pump previously, and the shop (dealer) that replaced the pump I guess did not notice the mess underneath .
I have also replaced a few of the vent hose assemblies, the part that goes into the head fails.
Seems all the PDs have a tendency to seep some oil at the rear corner of the valve cover and sometimes the tandem pump seal. Some worse than others. Lately I have had good success with new valve covers, as the gasket alone does not always get it sealed back up totally.

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Do you have the valve cover part number handy, I have all my leaks fixed but the rear right corner of the valve cover

038-103-469-ae

PickleRick said:

The only negative i can think of is it takes longer for the heat to work in the car. You're in Texas so this shouldn't be an issue.
Secondly, i believe your ecu needs a tweak when this is done so you dont throw a code. Hopefully someone else will chime in and let us both know 100%. My ecu is at a tuners shop as we speak for many other mods and i was asked about the egr delete.
I have ordered the block off plates. Im still not sure if the delete kit comes with the appropriate hose to finish off the delete, ill know in a few days when ups brings all my parts to me

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Ok so bottom line one the best solutions is for deleting the EGR/cooler but I need a tune of some sort to get the engine light off. Correct?

tikal said:

Ok so bottom line one the best solutions is for deleting the EGR/cooler but I need a tune of some sort to get the engine light off. Correct?

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Yes, the ECU will throw a MIL for the loss of EGR valve function. Any tuner can tune this out. Might be cheaper to just replace the leaking EGR cooler (and EGR if it's not working) than pay for a tune. But a tune will wake up the B5.5 (I had one and it was nice).

aja8888 said:

Yes, the ECU will throw a MIL for the loss of EGR valve function. Any tuner can tune this out. Might be cheaper to just replace the leaking EGR cooler (and EGR if it's not working) than pay for a tune. But a tune will wake up the B5.5 (I had one and it was nice).

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Thanks Tony for the feedback. In fact my car does have a tune (from Green Diesel Engineering) so I just emailed them to see if they have a solution for a an EGR delete option.

Does anybody have the part number for the EGR cooler handy? What I am looking at for parts/labor to R&R the EGR cooler?

Also I see there is another option to bypass the EGR cooler by looping the coolant hose and leaving the EGR intact. Would I get an engine light in this way?

tikal said:

Also I see there is another option to bypass the EGR cooler by looping the coolant hose and leaving the EGR intact. Would I get an engine light in this way?

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No, you'll just get superheated exhaust blasted into the intake. The EGR cooler is there for a reason, I'd not try and circumvent its ability to do its job while actually having an intact and functioning EGR.

oilhammer said:

No, you'll just get superheated exhaust blasted into the intake. The EGR cooler is there for a reason, I'd not try and circumvent its ability to do its job while actually having an intact and functioning EGR.

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Thanks OH. So no looping but an option would be an EGR/EGR cooler delete.

That would be an option, yes, if you like. Just remember, besides emission control, the EGR system (and cooler) does have some benefit. It does help bring waste heat from the exhaust into the heater core for cabin heat (that is why the EGR cooler is in the heater core loop), and that also makes the engine come up to operating temp faster which is better for the engine and better for fuel economy.

It also makes for a smoother, quieter idle (anyone that doubts this, sit and let your car idle for a few minutes, and you will notice right away when the ECU closes the EGR).

With USLD, plus the fact that the PDs never really had as much of an issue anyway, the intake clogging horror stories from years ago is in the past, and under most all normal operating conditions is a non issue. Plus, the tuners can actually use the EGR strategy to exploit the above mentioned benefits while also giving an extra bit of available power to the engine when called for.

My BHW has been tuned longer than not, and it still has its EGR system intact and [within the confines of the tuner's software) still working. Closing in on 200k miles now.

Ok, thanks for pointing out the trade-off of deleting or not the EGR.

Here is my BHW dilemma at this point: I have visible dry coolant residue on splatter pattern below coolant outlet overflow hole and today at the local shop I can see fresh coolant spots downward of the area (shop is a short 20 minute drive from my house all City traffic). Is it possible for an EGR cooler malfunction to force combustion gases into the coolant system and force the coolant out in this fashion?

Depending on the answer I need to make some important decision on how to proceed and could mean $$$ vs. $

tikal said:

Ok, thanks for pointing out the trade-off of deleting or not the EGR.
Here is my BHW dilemma at this point: I have visible dry coolant residue on splatter pattern below coolant outlet overflow hole and today at the local shop I can see fresh coolant spots downward of the area (shop is a short 20 minute drive from my house all City traffic). Is it possible for an EGR cooler malfunction to force combustion gases into the coolant system and force the coolant out in this fashion?
Depending on the answer I need to make some important decision on how to proceed and could mean $$$ vs. $

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See post #16, as that is the only way I have ever seen an EGR cooler on a BHW fail.

It is easy to pressure test the cooling system to find any external leaks. Takes less than a minute.

I hear you Brian. The pressure test was done at the end of February and nothing was shown to leak externally. Basically my conclusion is that all the coolant being lost is by the reservoir 'spitting' through the overflow hole which points downward. Basically the coolant is sprayed in the area and I can clearly see the residue marks. The little coolant that makes it further down does not reach the garage door but it evaporates.

So at this point with your inputs the EGR cannot be the culprit and I am facing the worst case scenario of the head gasket leak causing combustion gases to overpressurize the coolant system and forcing it out. I did some research on this forum and I see other 'victims' of this failure mode (head gasket leak) such as users quattroluvr (see his post on 1/22/14), Waldo lemieux (same thread), 96Brian (5/4/16 post), thebarnowl (mid 2016 time frame) and auntulna (5/17/16 post).

I bought my Passat with around 120K miles in 2012 and I have taken care of it as well as I can but I cannot say the same thing from the previous owner ��

Any other thoughts telling me I am not in the right track.

oilhammer said:

See post #16, as that is the only
way I have ever seen an EGR cooler on a BHW fail.
It is easy to pressure test the cooling system to find any external leaks. Takes less than a minute.

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A compression test or leak down test will allow you to diagnose that issue. A bore scope will also allow you to find it in many cases. Find a cylinder void of all carbon on the piston top? There is your cylinder that's getting water! Its amazing how nicely water will clean a cylinder.

Just to be clear, just because I have not SEEN a failure mode of a BHW EGR cooler as you describe, doesn't mean it cannot happen. Every 3.2L diesel Transit's EGR cooler fails like. So many, Ford extended the warranty on them.

But, it is pretty easy to see... start the engine up cold, and the coolant bottle will right away start gurgling. There is also a combustion byproduct testing device (gas and diesel are different) that can be placed over the bottle to see if the source of the sudden extra pressure is from that, but that alone will not isolate an EGR cooler or head gasket.

Compression test won't tell you squat. The engine has PLENTY of compression, an allowable difference in percentage would easily eclipse the amount of combustion passing into the water jacket to build up pressure.

Pumping high pressure into each cylinder might, but again you'd need a LOT of pressure, well beyond what any normal shop air can provide.