Seat Leon knocking sound from engine?

Tails142

So I went with my girlfriend last night to collect her new second hand car. It was arranged through her father who has getting it off a friend who sells cars so we figured it was a good deal, certainly a good price anyway, €3000 for a 00, 55k miles on the clock.

Anyway got up, it was dark, first rule of buying a car broken Anyway, car looked in pretty good condition exterior and interior wise, but started up the engine and was greeted with an awful loud knocking sound in rhythm with the revs.

My initial thoughts were oh crap, run away from this piece of crap. Anyway seller said he had just got it serviced cause he too was concerned about the tapping sound. He said the mechanic said this was a nromal sound for this year/model and they all do it. I checked the oil cap and noticed that there was some white residue on the cap which I believe suggests dodgy gasket/cylinder head and collant in the oil.

We decided to buy the car in the end as the seller said he would stand over the car if a fault arises in relation to the knocking. I tended not to believe him but he is a friend of a family friend :rolleyes: And given the price if the car does need some mechanical work up to say a grand, the car still will have been a good deal I think...

What do you guys reckon, is he right and saying this knocking is normal for this model or is the car experiencing some terminal bottom knocking that will probably kill it within a few months... feel like we may have made the wrong decision...

bazz26

Tails142 wrote:

So I went with my girlfriend last night to collect her new second hand car. It was arranged through her father who has getting it off a friend who sells cars so we figured it was a good deal, certainly a good price anyway, €3000 for a 00, 55k miles on the clock.

Anyway got up, it was dark, first rule of buying a car broken Anyway, car looked in pretty good condition exterior and interior wise, but started up the engine and was greeted with an awful loud knocking sound in rhythm with the revs.

My initial thoughts were oh crap, run away from this piece of crap. Anyway seller said he had just got it serviced cause he too was concerned about the tapping sound. He said the mechanic said this was a nromal sound for this year/model and they all do it. I checked the oil cap and noticed that there was some white residue on the cap which I believe suggests dodgy gasket/cylinder head and collant in the oil.

We decided to buy the car in the end as the seller said he would stand over the car if a fault arises in relation to the knocking. I tended not to believe him but he is a friend of a family friend :rolleyes: And given the price if the car does need some mechanical work up to say a grand, the car still will have been a good deal I think...

What do you guys reckon, is he right and saying this knocking is normal for this model or is the car experiencing some terminal bottom knocking that will probably kill it within a few months... feel like we may have made the wrong decision...

No idea what the knocking sound is but I would not take the word of the seller's mechanic that this is normal. A bit late now but it is always worth having someone mechanically minded with you when your sure of buying a used car. Maybe you should have your own mechanic check that knocking sound out just for peace of mind if nothing else.

Also the white residue on the inside of the oil cap may not mean the head gasket is on the way out, it could easily be as a result of the car being only used for short journeys. 55k miles (I presume is genuine) on a 7 year old car is rather low so this may this. Again a mechanic can check this. Was there any service history with the car to indicate what kind of use it got?

crosstownk

I agree with bazz on the white residue.

However - this 'knock' - is it an actual knock or is more like a sharp tapping sound? My guess is that it is a tapping sound and could easily be a faulty bucket tappet or possibly piston slap (less likely). Hydraulic tappets do give a bit of bother in VAG engines.

craichoe

Tails142 wrote:

So I went with my girlfriend last night to collect her new second hand car. It was arranged through her father who has getting it off a friend who sells cars so we figured it was a good deal, certainly a good price anyway, €3000 for a 00, 55k miles on the clock.

Anyway got up, it was dark, first rule of buying a car broken Anyway, car looked in pretty good condition exterior and interior wise, but started up the engine and was greeted with an awful loud knocking sound in rhythm with the revs.

My initial thoughts were oh crap, run away from this piece of crap. Anyway seller said he had just got it serviced cause he too was concerned about the tapping sound. He said the mechanic said this was a nromal sound for this year/model and they all do it. I checked the oil cap and noticed that there was some white residue on the cap which I believe suggests dodgy gasket/cylinder head and collant in the oil.

We decided to buy the car in the end as the seller said he would stand over the car if a fault arises in relation to the knocking. I tended not to believe him but he is a friend of a family friend :rolleyes: And given the price if the car does need some mechanical work up to say a grand, the car still will have been a good deal I think...

What do you guys reckon, is he right and saying this knocking is normal for this model or is the car experiencing some terminal bottom knocking that will probably kill it within a few months... feel like we may have made the wrong decision...

Jesus .. I think i know the guy that sold this car ! Does it have big alloys with low profile tyres on it ? Seal is gone on the passenger side door too. Cork reg perhaps ?

stevenmu

Is it a deep knocking noise, or more of a higher clicking or ticking noise ? The latter can be caused by a carbon filter (iirc it's between the engine and exhaust to reudce emmissions further before getting to the cat). If it is this you should be able to hear that it clearly comes from the drivers side of the engine bay when you have the bonnet up, it should also go away after driving for a while and it warms up. I didn't think they were fitted untill 01 or 02 models, but if that's what it is, then yes it's perfectly normal and nothing to worry about, but to be sure you should really get a mechanic to take a look.

crosstownk

stevenmu wrote:

Is it a deep knocking noise, or more of a higher clicking or ticking noise ? The latter can be caused by a carbon filter (iirc it's between the engine and exhaust to reudce emmissions further before getting to the cat). If it is this you should be able to hear that it clearly comes from the drivers side of the engine bay when you have the bonnet up, it should also go away after driving for a while and it warms up. I didn't think they were fitted untill 01 or 02 models, but if that's what it is, then yes it's perfectly normal and nothing to worry about, but to be sure you should really get a mechanic to take a look.

I don't think it's the carbon filter - the OP seems to indicate that the knock is related to engine speed

Tails142 wrote:

an awful loud knocking sound in rhythm with the revs.

junkyard

If it's anything like a VW I'd be walking away from it if I was you, what's the point in paying money for something your going to have to spend more money on? Why not buy a decent car to start with in the first place? Most of the VW's I've come across in this age bracket have major engine issues, piston slap is a lot more common than you may think, I'd say most of them suffer from it.

~~SKYHIGH~~

vw engines get very tappety, it's either the tappets that are gone OR the bottom end bearings are gone. If its tappets you can live with it but bottom end is another story as engine would be on the way out. Even if the car has just 50 odd k on the clock there is a chance the oil could have ran dangerously low at some point and did damage to the bottom end shells resulting in a distinctive knocking noise and increases as engine is revved higher. As time goes by it literally chews up the engine to pieces and a new engine would have to be installed.
I wouldnt have bought a car with any white gunky crap under the oil filler cap. I have seen cars with less then 30k have head gaskets go...

Friend or no friend it's no excuse to buy a lemon!