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Access
The timing chain tensioner is located on the passenger side of the
engine. The airbox, serpentine belt and upper idler pulley were removed
to get good access with the tools on hand, and to see better. Removing
the tensioner with all other parts in place is possible, but more difficult. |
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Close-up
Tensioner position behind idler pulley. The picture shows the
tensioner housing with the off-center spring retaining cap at the end.
The pulley was also removed because the pulley bolt did not allow enough
clearance for the 27-mm socket used on the tensioner housing. A standard
socket may be a better fit than the long socket shown below. |
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Removal
The 12-mm spring retaining cap must be removed first, otherwise the
tensioner will extend fully while it is being removed! The spring
and plastic pin come next. The tensioner housing is taken out last.
It can take a fair amount of force to break the housing loose, then it
can be unscrewed by hand, carefully to keep the tensioner pluger from moving. |
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Components
a - spring retaining cap
b - cap seal
c - spring inserted inside tensioner
d - plastic pin inserted inside the spring
e - tensioner housing
f - tensioner plunger |
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Extension measurement
The tensioner range is from about 8 to 18 mm (9 or 10 clicks).
Maximum extension on a normal older engine is probably between 11-15 mm.
Mine was extended to the limit, which explained the chain noise from the
timing cover. |
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Wear Marks
After a little cleaning with a rag and a brush, marks can be seen on
the back of the shaft, showing how the tensioner took up the slack as the
timing chain stretched. 10-11 marks are visible, so the tensioner
started at 7-8 mm and slowly extended to 18 mm over the life of the engine,
before it could no longer keep the chain tight. |
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Reassembly
First the latch on the tensioner housing is pressed down and the plunger
is pushed in to reset the tensioner. After that, re-assembly is in
reverse order, tensioner housing first, tighten to 47 lb-ft, then the cap
and spring with pin inserted. As the cap is screwed in, the spring
tension pushes the pluger out to take up slack in the chain. |
References
Haynes Ch. 2A-6.9
Saab EPC 2-0300
Torque Settings
Plug (spring), 16 lb-ft
Housing, 47 lb-ft |
Tools Used
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3/8 Ratchet, 3" extension, 6" extension
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12 mm socket (spring retaining cap)
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27 mm socket (tensionner housing)
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3/8 to 1/2 drive adapter for the 27 mm socket
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