Just completed a WP/TB swap on my daughter's 97 Intrepid Sport yesterday. The car just rolled 100K so, I thought I'd do some preventative maintenence on it. It had a 6 bolt WP, but parts store showed it to have a 3 bolt WP for a 97 3.5L. I've done 4 of these swaps now, years ranging from 94-97, and all but this 3.5L had a 3 bolt WP. My question is... how does one ID if a 3.5L has a 3 bolt or 6 bolt WP before teardown?
My 94 Concorde, 97 Concorde and 94 LHS all have a 3 bolt. My 97 Intrepid has a 6 bolt.
6 bolt w/p's are more expensive tho. When the engine blew up on the Intrepid, I swapped out the timing belt covers to switch over to a 3 bolt. I have 4 of them on the shelf.
Can anyone tell me why Chrysler switched to the 6 bolt pumps on 3.5L's? Is it 97 only thing? Premature failure on some years? For example... I have a 94 LHS. When I bought it from the original owners, it had 67K on the odometer, (now 76K), and the pump was weeping a little when I bought it. When I swapped the WP/TB in it, I was expecting to see OEM parts still in it, considering the low miles. To my surprise, the WP/TB had already been changed once, but while I was there, I did it all.
IIRC, all 1st gen 3.5's were produced at the Trenton, MI plant. It appears the first and only year for the 6 bolt w/p was 97. After comparing the two, the 6 bolt pulley is larger. An artical on Allpar.com states this slows down the impeller, reducing wear on the bearings. The timing belts are the same for both, as the tensioner mount has been moved slightly closer to center.