Loud knock when starts from cold........any thoughts?

[House]

My '96 Griff has developed a loud knock/thud from engine area when first starts up from cold. Sometimes followed by a couple more knocks once started. No other problems and runs fine. It's not driven that frequently this time of year (prob once or twice a month). Had a crawl underneath and nothing appears to be loose. Any idea what this might be/similar experience?

[rev-erend]

Could be anything .. from a broken engine mount rubber to .. well anything.

Best get someone to start it while you observe it. you ears will soon pin point the area the noise is from and a screw driver held on the ear and near the source of the noise normally pin points it.

[yellowgriff]

If this only happens when cold. The 1 & only journey should be to a mechanic who you trust..If its the bottom end of engine every time you start the car the more damage you are causing. The bigger the bill,hopefully it isn't to bigger job but if you leave it engine can in mechanical terms be FU,,ED... Get some one to look sooner than later....

[rev-erend]

yellowgriff said:

If this only happens when cold. The 1 & only journey should be to a mechanic who you trust..If its the bottom end of engine every time you start the car the more damage you are causing. The bigger the bill,hopefully it isn't to bigger job but if you leave it engine can in mechanical terms be FU,,ED... Get some one to look sooner than later....

Heck - if the noise is that bad then an AA low loader to a garage might be in order.

Or DIY if you are compitant.

[steve-V8s]

Is there clearance between the exhaust manifolds and the chassis rail both sides? You should just be able to slide your hand in. If one of the engine mounts has failed could be the engine is resting on the manifold on one side and that is what you can hear. Both of my manifold have dents in the lower tube so I guess it has happened in the past on my car.

[House]

Thanks for all suggestions. Will have a good rummage under bonnet at weekend and hope nothing too serious...

[350Matt]

From the sound of it, I don't think its bearings as these tend to rattle not give a 'donk'

Matt

[short_t]

as you dont appear to run the engine frequently you could disconnect the low tension and turn over the engine a few times, then re connect and see if you still get the same same noise, hopefully you will and its not engine orientated!!

[Loubaruch]

short_t said:

as you dont appear to run the engine frequently you could disconnect the low tension and turn over the engine a few times, then re connect and see if you still get the same same noise, hopefully you will and its not engine orientated!!

Might not proove anything!

As Steve-V8 has suggested banging against the exhaust due to worn engine mounts is highly likely and it will be the kick as the engine fires that causes the extra movement. Just cranking on the starter is unlikely to produce the required jolt.

[House]

.....first prize goes to rev-erend - it was a perished engine mount rubber - now replaced. Thanks for all advice and suggestions.

[rev-erend]

House said:

.....first prize goes to rev-erend - it was a perished engine mount rubber - now replaced. Thanks for all advice and suggestions.

Just have to decide where to put the trophy

Glad you sorted it..

[steve-V8s]

Can I have second prize please because I said the same thing, was just a few centiseconds later clicking the Submit button, go on, please, award me ssecond place, have got some room in the trophy cabinet.

[spend]

Just put the trophy in Steves cabinet Alan & then everyones a happy bunny

Whoever claims third place is going to get pants though