What are these stains?

[Wantabus]

Any idea the source of these stains underneath?
Is it coolant or oil?
Could this mean a big expenditure?

5 window short bus gmc 6 L gas engine

 

[o1marc]

All buses leak. Yours doesn't look like a major leak, just a small film, not an issue to worry about IMHO.

 

[Johnny Mullet]

Maybe transmission cooler lines. Inspect carefully and fix immediately.

 

[Tango-SKO]

Clean it up with a pressure washer, then monitor those areas till you find the source.

 

[solleks]

thats the rust prevention coating :biggrin:

 

[FamilyCircus]

In my humble opinion, thats not enough to worry about. DOT wouldnt bother unless its a puddling oil drip, thats just wet. Just keep an eye on the fluids and drive it.