Hi Everyone,

My '89 740 16V (210 K) just started making a noise today that sounds like a valve tapping or maybe piston slap. I can't tell which. It does it through all rpms,too. I checked the exhaust manifold gasket and that seems OK. Any thoughts? It doesn't run bad, but the noise worries me a bit. The timing belt and valves were redone 2 years ago due to a broken timing belt (done by a Volvo tech).

Cheers,
Dave

Hi Dave,

Hmmmmm, I'm not a B234F expert, but I know a bit about them. It may be a sticking valve. What brand and weight of oil do you use in it? How often do you change the oil? It might be a good idea to pour in a good "engine flush", run the engine (following the instructions) and then change the oil. This might cure the problem if it's a sticking valve. If after you change the oil the noise is still there, try driving the car harder then usual (letting the engine rev higher, etc) for a few minutes, ocassionally this can help a lasy lifter get back on track. Piston slap is usually only apparent at idle or under ~1500 RPM. Sometimes it can be apparent at higher revs, but usually disapears once the engine is warm. Hopefully this will help you :)
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Chris. Halifax N.S. '91 745Ti, 289K km and '91 745 NA, 374K km.

Hi Chris,

Thanks for the quick response. I just bought the car about a month ago. I knew that the cylinder head had been gone through by a local Volvo shop. I use Valvoline 20-50W in it since we usually don't have extremely cold winters here in WV. I also use the Mann filters in all of my Volvos. I'll check for some engine flush at the local auto parts outlet. I've heard from several people on brickboard to use Mobil one synthetic in these cars. I presume it extends the oil change intervals.

Cheers,
Dave

Hi Dave,

I agree with Alex, 20W50 is too thick. According to the Volvo owners manual, the thickest oil that should be used in a B230F/FT or B234F is 15W40 and that is ment for severe operating conditions. I use Shell Rotella T 15W40 (changed every ~3K mi) in my B230F, because it has fairly high mileage (~234K mi), it's a high quality oil and I tend to drive the car a little hard because I'm use to my turbo :) Synthetic oil is great, but before switching over make sure the engine seals aren't leaking. Any leak will get bigger with synthetic oil. I use Amsoil 10W40 in my B230FT and change it every 5K mi. So, I'd get rid of that 20W50 and put in something lighter for sure, wheather it be synthetic or not. If you go synthetic you will have to use an engine flush before the switchover. Hope this helps! :)
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Chris. Halifax N.S. '91 745Ti, 289K km and '91 745 NA, 375K km.

Hi Chris and Alex,

Thanks for the responses. I'll get some lighter oil for sure. I guess I'm used to using the 20W-50 in my MGBs. Several MG enthusiasts have told me to use that weight, but the Volvo's engine is quite different. What about getting a part synthetic oil like the kind that Valvoline makes?

Cheers,
Dave

Hi Dave,

No prob. Yeah, a B234F is quite a bit different then the engine in a MGB, especially with the 16V head. A part synthetic oil would work, but there's really no point. With that you can't safely extend the drain interval so you should just buy a good non-synthetic like Castrol, Penzoil, Valvoline etc. Maybe the "High mileage" version. If you're going with non-synthetic you might want to try a good diesel oil like Shell Rotella T, Chevron, Mobil, etc. It's up to you, non-syn is fine, just make sure you keep it clean. Let us know how you make out.
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Chris. Halifax N.S. '91 745Ti, 289K km and '91 745 NA, 375K km.

Hi Chris,

My main concern about using the synthetic oil is that the '89 16 V already has some oil leaks. The bellhousing of the transmission/rear of the engine stays soaked. I'm thinking maybe it's the rear main seal leaking. I don't see any other leaks though. I'm not sure that I want to pull the transmission right now to fix the leak since it isn't that bad. Then again, it would be better than trying to do it this winter.

Cheers,
Dave

Modern synthetic in best in all engines,fluswh w 1/2 bottle flush drive slowly for 30 mins 25b mph,,that loosened all the crap in my 280.000 mile engine drained all overnight,new filter ,[pull cap wire off so it doesnt start ] put new copper washer,,no leaks for 6 mos!!see if that cures the sound,,

Hello Peter, I haven't heard from you in a while,

Full Synthetic is the way to go, it's made from natural gas instead of crude oil and doesn't have the impurities common to dyno oil that clog up engines.
Mobil-1 tech says use 5W-40 Euro blend in my B230FT.
Castrol and Penzoil are running summer specials, Mobil-1 $20 off ended Aug 31st.
see here for the Castrol promo:

https://www.brickboard.com/RWD/volvo/1689642/940/960/980/V90/S90/castrol_promo.html

Summer is the time to stock up on Synthetic oil.

I got my 945T two years ago and it was always run with dyno oil.
I switched to Mobil-1. In short order the oil turned a very evil black
as the synthetic was cleaning out the mess from dyno oil.

I don't like the idea of a harsh engine flush and the chance to dislodge some evil chunks of gunk in the engine to maybe have it get stuck in some oil passages. A few changes of Synthetic will clean that mess out safely.
I changed out the mobil-1 and Mann filter twice in 3K miles/2 years and on the third shot of 5-40 this latest Castrol Edge API SN/CF is staying clean now

If you have a slow weeping leak you can have luck with Rear Main Seal (RMS) treatments. One local pro mechanic said that a capful (1 tsp) Maximum of brake fluid in the oil will work to swell leaking oil seals.
That's about right, go to the local auto parts and buy RMS treatment: a quart of oil with 1 tsp. of brake fluid for $12.00 + Tax

That reminds me of getting this chemical at the tropical fish store to reduce
acidity. They never told you it was just soda bicarb and sold you an ounce
marked up 2000 %. Business is business eh?

Yes a weeping oil seal weeps a bit more when you switch over to full synthetic,
but it stopped after about 1500 miles with the RMS stuff and full synthetic.
(This was in a 5 cyl 850 that needed major TLC to repair the damage of dyno oil)

Cheers, Bill

Hi Dave,

Well, if your not up to changing the leaking seal right now, then I'd say stay away from synthetic until the leak is fixed. I don't use synthetic in my B230F mostly because of it's mileage and therefore I'm afraid that it'll start leaking. I chose Shell Rotella T for it because it's supposed to be a high quality oil and I wanted something a little thicker then 10W30. I'd recommend you just try something like Castrol, Penzoil or Valvoline non-synthetic 10W30 for now and see how it likes that. You still might consider using an engine flush as it should help with the (sounds like) lifter problem, hopefully.
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Chris. Halifax N.S. '91 745Ti, 289K km and '91 745 NA, 375K km.

That oil is probably way too thick. Go for 5w30 or 10w30. If the noise goes away after a while you've probably got worn hydraulic lifers. Thinner oil should pump up faster in colder temperatures. If the noise doesn't go away, it could be the piston slap that's oh so common on the red block motors. If the noise doesn't change with engine speed, it's probably the fuel injectors.

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alex

'89 765T, 175,4xx mi