Piston Slap

[Mark1Stu]

I’ve a B200E engined 240 with 107k on the clock. It pulls well and sounds sweet at idle when warm. From a cold start however, under any kind of load, it’s noisy until up to temperature. I’ve checked numerous components, reset the valve shims etc. Assuming it is piston slap (it’s a familiar sound) I’m just wondering what expense awaits and how to minimise it. OK, I could live with it for many more thousands of miles, or buy a secondhand replacement engine - perhaps of dubious history. However, I seem to remember my exVolvo mechanic (now retired) say he’s changed the pistons in these engines before ‘because they’ve worn out : and I’ve read and seen engines with more miles still showing cross hatching on the bores. So my question is, would it be possible and in fact perfectly reasonable (assuming no damage to bores found) to simply swap the pistons for replacements and carry across the existing rings set to the same gap location on the new piston as when removed. Or, is the cause of piston slap a combination of wear to pistons, bores, conrod small ends etc

I appreciate I could go for a more comprehensive recondition (Id check the crank shells while I was at it) but given the miles and the fact the engine appears strong and they are known for galactic mileage, is what I’m suggesting realistic?

Interested in your thoughts / experience.

Thanks.

[Chris1Roll]

From my research on the subject, I found that people said their cars started slapping at pretty low miles from new.
Also found a few that rebuilt engines because of it, only for it to come back after a few thousand miles.

My B200E slaps like an abusive stepparent when it's cold, but is fine once warmed up.

The consensus seems to be that they can do (literally) hundreds of thousands of miles like it.

My plan is to ignore until it starts doing it when warm, which will be my excuse to fit a B230E if I haven't already by that point.

I was on the 240/740/940 Facebook group a while back and someone posted a video of a slappy one. The top comment was "It sounds like it's running"

Others my have a different opinion but personally I'm not going to spend the money to rework a B200, I'll rebuild a B230 to put in its place.

[john.wigley]

If the racket is not excessive, I have found in the past that the addition of Molyslip to the engine oil may help to quieten a vocal motor. It is not a 'cure-all', may not work at all and is by no means permanent, but as a low-cost temporary expedient, it might be worth a try?

Regards, John.

[Mark1Stu]

Thanks John. I’ve tried that but I think the piston slap has advanced too far.

[Clifford Pope]

I've always taken this as a case of "they all do it" and ignored it.
I think the 230 is more prone than the 200 because of the wider bore.
If it pretty much disappears when the engine has warmed up I don't think there is anything to worry about.
The engines have never been the kind to idle silently - tock rather than tick

[142 Guy]

In 1985 Volvo introduced a low friction version of the B200 and B230. This included pistons with abbreviated skirts. I had a B230 FT in my 1987 745 turbo and it developed piston slap (pretty much as you described) at about 100,000 km which was most noticeable on the #4 cylinder. I talked to a local Volvo tech about it and he said that all the low friction engines did it and don't bother trying to fix it because it will just re appear in 3-5 years depending on how much you drive the car. Noise always went away after the engine was hot.

I think around 1989 Volvo made some more engine revisions that eliminated the problem (good bye short piston skirts or perhaps the oil squirters?).

[morsing]

Mine's an '89, I've driven it for over 250 000 miles and it's never made any noises.

Regards,
Henrik Morsing

[HWFrush]

I have '20 XC40 with 35,000 miles on it. The noise, when cold, is tremendous. In the summer there is not a problem. It's not the miles in my case because it has been that way from the first cold day. Although, it does seem louder now.