how to tell if my timng belt has slipped by visual inspection? on 1991 Volvo 940

need to determine if my timing belt has slipped by looking at it

Asked by for the 1991 Volvo 940
You would need to remove the timing cover and verify timing marks, or bring number 1 cylinder up to top dead center and see if the valves are closed in that cylinder. If the engine runs it should produce 18.5 to 21 in HG vacuum, lower vacuum may indicate incorrect timing. Autozone have some popular workshop manuals for free on line once you register (for free) on their website There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate