Piston Slap: Ronnie Schreiber Gets Piston Slapped

Sajeev Mehta
by Sajeev Mehta

TTAC’s analyst extraordinaire, Ronnie Schreiber writes:

My daughter has a Volvo 940. The local Volvo mechanic said that the noise it’s making is the #1 piston hitting the head because of a sloppy big end bearing, which explains the low oil pressure at idle. I was thinking that 60 or 70 years ago, a mechanic might have fixed just the bad bearing, without rebuilding the engine. I was thinking just to do a quick fix, I could drop the oil pan, take off the offending rod cap, mic the crankshaft journal, buy the best fitting bearing per the crank measurement, and bolt everything together with the new bearing. So, Sajeev, with this true piston slap question, is it worth it to try a cheap engine repair like this?

Sajeev replies:

I’d run with that plan, though a small part of me insists on pulling the motor and replacing all bearings. And gaskets, since you’re going in there. Or, conversely, getting another motor if you have over 200k on the clock. That said, let’s bring in TTAC’s resident Volvo-guru, Alex Dykes:

Alex replies:

Ronnie, sounds like you’re on the right track to me. Given the age of the 940 I’m assuming you’ve probably put on more than 100,000 miles already? Since it sounds like you’re a handy guy, I’d give this fix a try before I did anything else. If this doesn’t fix it, then I’d just run out and grab an engine of the same displacement from any Volvo 740, 780, 940 or 960. The 700 and 900 series are often considered the last of the “bullet proof” Volvos so overall I’d say this fix, or even a used engine would be a worthwhile repair. Be sure to check out prices on used 940s, 960s and S90s before you explore a used engine, with the recent trends in used car values, you might be able to pick up a whole car cheaper.

[Send your queries to mehta@ttac.com]

Sajeev Mehta
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  • Steven Lang Steven Lang on Sep 21, 2009

    Ronnie, if you're in Atlanta I have an engine and tranny with 105k, leather seats, and a whole lot of other doo-dads for the same model. Let me know if you are...

  • ZZ ZZ on Sep 21, 2009

    A few quick words since it's a busy Monday for me. #1 - Brickboard.com and 700/900 Series FAQ. #2 - If there are more serious problems, it would almost have to be more cost effective to pull the engine out and swap with a good one from a yard. Don't know where you're located, but they should be plentiful enough to find a decent example with mileage somewhere in the 100k range. Access is pretty easy in the engine bay - a little more crowded than a 200 series, but still everythign is there. (currently at 278k mi on my 1990 245DL, eyeballing a '92) Best of luck. Z

  • Lichtronamo Watch as the non-us based automakers shift more production to Mexico in the future.
  • 28-Cars-Later " Electrek recently dug around in Tesla’s online parts catalog and found that the windshield costs a whopping $1,900 to replace.To be fair, that’s around what a Mercedes S-Class or Rivian windshield costs, but the Tesla’s glass is unique because of its shape. It’s also worth noting that most insurance plans have glass replacement options that can make the repair a low- or zero-cost issue. "Now I understand why my insurance is so high despite no claims for years and about 7,500 annual miles between three cars.
  • AMcA My theory is that that when the Big 3 gave away the store to the UAW in the last contract, there was a side deal in which the UAW promised to go after the non-organized transplant plants. Even the UAW understands that if the wage differential gets too high it's gonna kill the golden goose.
  • MKizzy Why else does range matter? Because in the EV advocate's dream scenario of a post-ICE future, the average multi-car household will find itself with more EVs in their garages and driveways than places to plug them in or the capacity to charge then all at once without significant electrical upgrades. Unless each vehicle has enough range to allow for multiple days without plugging in, fighting over charging access in multi-EV households will be right up there with finances for causes of domestic strife.
  • 28-Cars-Later WSJ blurb in Think or Swim:Workers at Volkswagen's Tennessee factory voted to join the United Auto Workers, marking a historic win for the 89- year-old union that is seeking to expand where it has struggled before, with foreign-owned factories in the South.The vote is a breakthrough for the UAW, whose membership has shrunk by about three-quarters since the 1970s, to less than 400,000 workers last year.UAW leaders have hitched their growth ambitions to organizing nonunion auto factories, many of which are in southern states where the Detroit-based labor group has failed several times and antiunion sentiment abounds."People are ready for change," said Kelcey Smith, 48, who has worked in the VW plant's paint shop for about a year, after leaving his job at an Amazon.com warehouse in town. "We look forward to making history and bringing change throughout the entire South."   ...Start the clock on a Chattanooga shutdown.
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