Good tip, but ask them what they spray with or is it straight water,detergent or some bio-degradable solution diluted.
Just watch they are being carefull not to blast with too much force around bearings & UJ's.
Remember detergent can be corrosive, really requires good rinsing
& depending on what they use you may need to re-grease & lube.
At least you are going under a clean motor to do your checks & maintance.
george
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