AGR Cooling: Is it Harmful?

Hello,

A soot pump inspection or cleaning of the EGR system on an ALH G4 is scheduled soon.
When the suction hose is removed, it becomes apparent that the active EGR system has likely been working for at least around 200,000 kilometers and requires some maintenance.

Ideally, the engine should be cool before starting any work (i.e., at least removing the EGR unit). However, this is hardly possible because the car doesn't belong to me and it was only started shortly beforehand.

To avoid damaging anything unnecessarily (especially when loosening the screws on the EGR pipe leading to the turbocharger), I would like to cool down the EGR unit with water.
After a short period of engine operation, the heat from the cylinder head gradually travels through the intake manifold and into the EGR system. Therefore, pouring water into it would cause a sudden temperature drop of approximately 60-70 Kelvin.

Is this critical with regard to thermal material stresses (like in an exhaust manifold), or can the relatively soft aluminum easily withstand such temperature fluctuations?
It would be embarrassing if the relatively expensive EGR unit fails during the process...
I would definitely cover the exhaust muffler from underneath to protect it from water.

Hi Ulf,

I've now gained some experience with hot-rodding in the evenings.

The exhaust manifold EGR pipe is so thin-walled that it cools down relatively quickly. (The pipe was cold, and I even burned my fingers on the valve cover because of it.)
But only the two Allen screws are relevant here, because you can leave the pipe attached to the bend.

You can touch the AGR unit with a glove and remove the three Allen screws that connect to the intake manifold without touching them directly.

I might consider placing a fan above it to cool it down.

Taking a shower would be too risky for me, especially because of the possibility of encountering other people's vehicles.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

A steam cleaner (a high-pressure washer with heating) is very useful for this. Once the exhaust manifold, turbocharger, etc., have cooled down to approximately coolant temperature, you blast them thoroughly with hot steam from the steam cleaner. An assistant stands by the temperature control and slowly lowers it until it reaches around 30°C.

'It works great, and it also cleans the engine. I've used it on my 3B and my AAZ before...'

Nebelwerfer_TDI wrote:

A steam cleaner (a high-pressure washer with heating) can be very helpful in this situation.

"Sure, but first things first: in a parking garage like ours, that's simply not possible."

By the way, when I thought about a shower, I was actually thinking of an old canister that might have been used for antifreeze or something similar.

Quote:

The exhaust manifold EGR pipe is so thin-walled that it cools down relatively quickly. (the pipe was cold, which is why I burned my fingers on the valve cover). But there are only the two Allen screws that are relevant, because you can keep the pipe fixed to the bend.

... and to prevent the Allen keys from falling into the depths of the engine compartment, you have to use your fingertips to carefully unscrew them the last bit and hold them. In my opinion, it's hardly possible not to touch the AGR valve during this process... and wearing gloves makes it impossible to feel how tightly you're holding the screw .
That's why I had the idea of a cold shower.

ulf wrote:

... By the way, when I thought about a shower, I was actually thinking of an old canister that might have been used for antifreeze or something similar. ...

Use a fine mist spray bottle or wrap a damp cloth around it. This will limit the temperature shock because not as much water evaporates at once, while still allowing it to cool down quickly.

joegolf wrote:

Try using a fine mist spray bottle or wrapping a damp cloth around it; this will limit the temperature shock because not as much water evaporates at once, and it still cools down quickly.

Okay, that would be feasible.

. . . certainly, but first of all: in a parking garage like ours, that simply isn't possible.


'That's correct; however, I would request that the person come to me, as I don't have the tools and materials needed for unexpected situations (like a dropped screw) in the parking lot.'