GMC 1993 Suburban Owner's Manual page 366

It is important for you or a service station attendant to perform these
under-hood checks at each fuel fill.
8
Check the engine oil level and add i f necessary.
Q
Check the engine coolant level in the recovery bottle and add i f
*
Check the windshield washer fluid level and add if necessary.
necessary.
See these items in the Index for information on how to check them.
i
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