1988 Volvo 340 engine query

Hi all,

I have become slightly concerned by a faint, loose rattly type noise from the engine of my Volvo 340 (1400cc). A typical egample of when the noise last occured, was when I was making my way along a dual carriageway at a steady 55mph in fourth gear. When climbing a gradient, the loose sounding noise started after I pressed the accelerator in order to maintain the same 55mph. It then disappeared after the climb. It also occurs if you increase speed from 50mph to 60mph, for example, when making the engine work.

The strange thing is, I have heard a similar type noise from other cars' engines when the drivers are labouring them, i.e. Too low a speed for the gear, making the engine struggle. Except mine is not struggling at that speed.

The engine appears in good condition and does'nt use any oil. The tappets have recently been checked, and I change the oil & filter around every 3,000 miles. Car has covered about 58,000 miles and I use castrol GTX magnatec Semi-synt oil.

Any ideas what this might be? I would be grateful for any comments.

Thank you, Matzur

[pettaw]

rattling under load? Would need to hear the noise personally but I would suspect worn big ends unless anyone has any other suggestions.

You could possibly check the propshaft clamps for tightness as they can work loose and cause a rattling/grinding under heavy load. Other than that I dunno!

[srtames]

Sounds like pinking . Check your plug colour. If they are white you may have a blocked main jet (take off carb top and main jet is at bottom of bowl for Weber) or an air leak on the inlet manifold.

Regards, Steve

[sheerwater]

If I remember right the 340 was originally designed for a higher octane fuel than todays 95 unleaded. Wasnt there an adjustment that could be done by moving/swopping/adding a wire to the ignition unit to let it accept lower grade fuel?? Maybe someone can advise. Cheers Nige

I had a strange grinding rattle at a particular Rev. which turned out to be a broken top pipe on the exhaust. It was a crack that was impossible to see without taking it out. I had it changed and the same thing happened to the new one after a week. Maybe it is a common fault???
The second one fitted has been OK for a few months.
Petter

[pettaw]

Yep, on the 340 1.4s you can ground the 'B' terminal. But only on pre 1987 models All post 87 models already have the conversion done

Andy

Thank you everyone for your suggestions.

I think I will treat this problem as pinking, as one of you mentioned, and try to find the likely cause.

The reason for this is because I have read that engine damage can result if left untreated, and the car does show the classic symptoms of pinking. Therefore, I plan to have the car serviced at a recommended garage.

I would be most grateful if those of you in the know would kindly list all the things that need to be checked (in addition to the replies above) with this problem, so I can show the mechanic what I want him to check, in case he should overlook something.

I'll let you know of my progress when I eventually have enough money in my account to be able to pay the garage a visit.

Thank you all again for your help, and fingers crossed,

Matt.......