960 Engine Knocking When Engine Cold

92 960 · Post by **92 960** » 15 May 2004, 14:37

Hi guys, I'm sure you are all aware that most mechanics are on the learning curve with 960. The valves being hydraulic require very different driving habits in this car. I know this is not normal but I would stay away from aditves. Stick to a premium grade if you can and use sythetic oil at 5K interval to prevent further problems. To solve the sticking exust valve rpoblem, warm the car up and take it on the freeway, at about 35 shift to "L" which is (second gear at that speed, not first) get it up to 5000 RPM and keep it there for a good ten minutes. This will rotate the valves and and loosen things up. You cant damge the engine, on the contraire it will idle better and run much smoother after this. Also don't ever start the car to move it a few feet and shut it off befotre warming up. You risk serious valve sticking problems from doing this. I always drive it atleest a few miles before shuting it down. Its a great car as long as the timming belt is changed every 30K (uptil 1994) and the cooliing sytem is new. http://www.brickboard.com

Al 92 960 200K

Volvord · Post by **Volvord** » 15 May 2004, 16:03

A couple of things:

First fuel additive will have no effect on hydraulic lifters, in fact a fuel additive that acts as an injector cleaner is benificial and should be used on a regular basis to keep injectors clean. These additives are not a saving grace solution but they can help maintain good fuel pattern and delivery.

Second thing is hydraulc lifters have been around for years, and although they are new to Volvo every American V8 has used them for over 50 years. Yes they will gum up and stick if you fail to service your engine regularly. Short drives result in higher level of moisture in the engine caused by condensation but there is not an advantage to running the engine for a few minutes vs 10 minutes or a couple of miles. To reduce or eliminate the moisture build up in the engine/oil requires the engine oil temperature to rise to a temperate of about 220 deg, this will take a while. Regular oil changes with high quality oil is a definite, every 3000-5000km with a synthetic oil is the best.

A good run on the highway is always benificial, but running an engine at a constant 5000 rpm is not needed, just a prolonged run where the oil and combustion chamber temperatures are maintained for a long period will "burn off" combustion chamber deposits and result in a better running engine.

And finally do change your timing bely regularly, every 30,000 will definitly prevent you from ever experiencing a broken belt, but for economic reasons for someone who has to have a mechanic change the belt every 50,000km is more often than is recommended by Volvo and you should not have any troubles.

arete · Post by **arete** » 19 May 2004, 07:12

I have a 81 240. It always knocks/noisy on first start until I go several miles. I always figured it was a lub/oil issue. The oil finally is warm enough to fully lub the engine.

LaRy · Post by **LaRy** » 19 May 2004, 11:05

I agree with Volvord that you may hear a slight piston slap. When the pistons are cold there is more clearence between the piston skirts and the cylinder wall, as the engine runs the piston will rock slightly in the bore. As the engine warms up the piston will expand and the noise will dissappear. This is the answer a got from an engineer working for Volvo in Sweden, when I noticed the same thing in my 740. This sound began in 1986 when the B230 enginge was introduced as a low friction engine. The design of the piston was now shorter to reduce the friction, at the same time the piston will rock slightly when it is cold.

ACrombe · Post by **ACrombe** » 23 May 2004, 09:40

The 4 valve/cylinder engines use small valves and the accompanying lighter valve springs. The exhaust valves will on any engine get some accumulation of deposits, primarily from fuel combustion with some portion from oil that seeps through guides for valve stem lubrication, that in some situations can cause the valve to slightly bind in guide.

petershen1984 · Post by **petershen1984** » 23 May 2004, 20:10

The 5500 rpm run is practiced by mechanics, but it sounds very loud and dangerous with the car in motion on the highway, doing 55 mph (88 km/h) in low gear. If you're going to try this, park the car somewhere and rev the engine freely.

Same burning-off effect achieved using less fuel.

A.Baker · Post by **A.Baker** » 25 May 2004, 04:21

There is a tsb from volvo that addresses a noise that you describe in it there is a procdure for changing the front main crank bearing only. go to volvo.com become a member for free and you will have access to everything about your car. some info costs but a lot is free.Once a month I get a list of new TSB's,and updates. hope this helps.
A Baker