Does My Engine Need Replacing?

[Guest Straker]

Hi,

 

I (stupidly) bought a mk 3 ford mondeo, 2.0 litre, zetec (with duratec engine), manual, petrol. It is a low mileage x reg (feb 2001).

 

The engine makes an unearthly klonking noise. I immediately took it to my local garage and, before I stepped in the door, the mechanic came out and told me it needed a replacement engine. He basically said the engine was knackered. It is definitely an internal engine problem rather than a structural or driving problem as it is in sync with the engine turning over. The thing I don't understand is that the car seems to drive perfectly, power feels good and the klonking noise does not seem to have any effect on the running of the engine. Having said that it really is loud and I was quite anxious when driving to the garage as I wasn't sure that I would make it there.

 

Could it be that replacing the whole engine is a bit drastic and some internal parts might be renewed instead? I realise it is extremely difficult to give advice without hearing the noise but anyone's thoughts would be greatly appreciated.

 

thanks

[Guest j_mchattie]

Theres not many people with x-ray eyes (although there was this one guy....), so a garage that makes an opinion without even opening the bonnet needs a slap or seven.

 

Can you describe the sound at all? Is it metallic? Bassy? High pitch or low? Clonk? Rattle? Is there any vibration?

 

You mention it co-insides with revs, is there a rev range where the sound goes quiet?

 

Does pushing the clutch down make any difference?

 

I guess all your fluids are ok, and that its not just collapsed tappets? Is the rattle from the engine - or nearby? Left or right? Gearbox? High/Low? Clutch?

 

Does it get worse/better under heavy load?

 

I wouldnt take 'your engines knackered' as an answer - there will be tons of good parts, and only a few to replace if the engine still runs ok. But like you say - its difficult to describe on a forum.

[Guest Straker]

Hi,

 

Thanks for the reply.

 

I could only describe the noise as being 'clonky'. Coming from the engine but I couldn't say whether it was from the upper or lower section. Not really metallic, quite bassy rather than high pitched, a bit like someone frantically trying to batter their way out of a wardrobe. After initially saying the engine needing replacing (before inspecting anything) the mechanic flipped the bonnet and removed the rocker cover. He then confirmed his initial diagnosis and mentioned something about the pistons hitting something, apologies I can't be more specific. My question to this is - if the pistons are making the noise when battering something shouldn't the noise be a lot more rapid, ie - in time with the revs of the engine? Whilst the engine does clonk quicker in sync with revs it does not clonk exactly as quickly as the revs in the engine. By this I mean when the engine is at 2000 rpm the noise is not clonking 2000 times per minute. My ignorance concerning mechanics probably means this does not have to be the case in order to indicate that the pistons or something similar are hitting something. Furthermore, if it was as severe as that would the performance of the car not be effected?

 

I have possibly just confused the matter with this reply but your thoughts are greatly appreciated.

 

thanks

[Guest Straker]

Sorry, I should also add that from the drivers seat I did not feel any vibrations. The engine seems to take a few minutes to warm up before clonking starts and there seems to be a lag sometimes when accelerating before the klonking also accelerates.

 

I am taking it to a Ford dealer today so hopefully they will give me an alternative diagnosis.

 

I shall let you know what they say.

 

thanks

[Guest j_mchattie]

It sounds like the pistons are hitting your valves!

 

Which would tie in with it not sounding 2000 times at 2000rpm - but less.

 

I would however be suprised if the engine even ran if the timing was incorrect - let alone with full power still there.

 

Its perhaps a good sign that it only happens when the engine is warm - indicating that the oil may have something to do with it. Maybe its thick enough to stay in the hydraulic tappets when cold, but too thin when hot and it leaks past the valve. But this would just cause tappet rattle - not the bass you mention.

 

It could be that simply the ECU is making the spark plugs fire too early - and ramming the valves closed before they should be.

 

If the head gasket has blown, the engine could be forcing very high pressures into the oil system which would certainly cause your tappets to fill all the way up. This in turn would hold your valves slightly open all the time, and allow the piston to collide with them. It might only happen when hot - as you mention.

 

If your pistons are colliding with anything else, then there is something drastically wrong - but you would know about that! You would have loads of excess vibration.

 

So I would go with:

 

a)Sticky Valves

b)Wrong Oil

c)Blown Head Gasket

 

If the Valves have been hit - they will need replacing, as might the head (which is a good excuse for a new head gasket anyway). See what Ford say - and let us know