Garage wrongly diagonsed problem

[Debtworry]

Hi all,

 

I have had a problem with my Golf TDI, when i started i would get a knocking sound that would last a few seconds then stop, it wouldn't happen all the time just when the car felt like it, either hot or cold.

 

As i wanted to sell the car, i took it to a VW specialist who removed the rocker cover and told me i had camshaft problems, i told them to carry out the work at a cost of £1200 as i needed a new cambelt water pump tappets and belts.

 

Anyway, a day or two after getting the car back, the knocking sound is still present

 

I had to borrow half the £1200 so there is no way i can afford to have more work done.

 

A friend of mine said to go back to the garage and ask for the £1200 back as it clearly wasn't what they said, and they have charged me for something that didn't need doing, he said if they dont play ball take them to a small claims court.

 

So thats the reason i am here, to ask for your advice.

 

Thanks

[saintly_1]

Hi I have moved your thread to the Garage Services Forum

[heliosuk]

On the face of it, the diagnosis is plausible, the water pump questionable as is the total cost.

 

The knock you hear initially is usually due to the hydraulic tappets not holding pressure and is not unusual for high mileage engines. The noise should disappear within 2 to 3 seconds of starting. It's not right but is concurrent with high mileage engines or engines that have not had regular oil changes.

 

As you have had this done and the problem is still there then I'd look at the oil pressure relief valve spring and seating. This obviously presumes they have changed all the tappets. Then I'd look at the oil pump pressure itself.

 

Tis hard to say based on this info above.

 

My neighbour has one of these so will look if it's possible to change the tappets without removing the head. The water pump, unless showing signs of leakage, sould not require changing but I can understand them doing this at the same time as a belt and braces so to speak.

 

Cambelts should be changed everytime they are removed but does depened on " engineers opinion". For example, if I had one on my own car that needed to be removed again after 1500 miles then I'd use it again but if it had done 10K miles then I'd have it changed.

 

Perhaps give the mileage and we could give advice as to likely cause. Also where in UK are you. If in south east/London then 1200 could be reasonable.

[Debtworry]

Thanks for the reply,

 

All the tappets have been changed, and the reason they changed water pump was because they changed cambelt and if the water pump failed then it will be expense to replace as the cambelt needs to come off again.

 

I am in South East London, hence the price, but with the knocking sound still present i am £1200 out of pocket with the same problem, that the garage told me would be cured as the camshaft was worn.

[heliosuk]

Ok, so we seem to have a relativly sensible garage. So far they have done everything correctly and in your best interests.

 

However I have an issue with the camshaft being worn.

 

If this was the case, why was it not changed. Your hydraulic tappets compensate for wear on the camshaft up to a certain extent. Basic feeler gauges would have told them this and if the cam was worn beyond limits or not.

 

The tappets rely on oil pressure to work correctly. There is a fraction of a second when the engine starts when it will be low but the tappets should hold this pressure so no noise. I think based on what you have said it is highly unlikely there is a faulty/worn cam shaft.

 

I would be looking at the feed to the tapetts. Again I' need to know the mileage and year.

 

To cure ( based on mileage and service history ) I'd drain oil, run up on flushing oil to try and clear out the oilways and releif valve.

 

It's an oil pressure problem you have here. It should not really involve anymore dismantling at the moment.

 

Frankly, depending on age and mileage, it might be an idea to leave it alone. Provided the oil level is correct and the knock does not go beyond 1 to 2 seconds then I'd leave it.

[Debtworry]

Thanks again for replying mate.

 

The car is 2002' on 104k miles with full service history. Around a month ago my brother-in-law flushed the engine twice.

 

If it wasn't for the fact i wanted to sell the car, i would have left the knocking, but on one or two occassions it has knocked for longer up until i drove then it went quiet.

 

So need to know where i stand in regards to the garage telling me it was camshaft when it clearly isn't, and as i'm not mechanically minded i had to take there word for it.

[blipvert]

Did the garage use a mechanics stethoscope, have you thought about using one, they are very simple to use and may yield vital clues. If you can find the source of the knocking using one then I'd say the garage were negligent.

[Conniff]

Why do garages always jump in at the deep end, is it profit motivation or a simple lack of professional experience.

 

104, would push me towards tappets, but I wouldn't just renew the whole top end.

 

You need to have a talk with the manager and ask him what he intends to do about the mis-diagnosis. You could insiste that he removes all the new bits (not cam belt and bits) and puts back your old stuff.

[heliosuk]

I don't think they have a wrong diagnosis here. Replacement of all tappets is a recommended procedure for many manufacturers and good engineering practise. It is wholly unreasonable to ask them to remove the parts replaced. On the basis of info provided so far I think the garage have done the right thing. The cam being worn is the questionable one as if it was then there is no point in replacing the tappets.

Go back to the engineering basics chaps. If the cam is OK, tappetts replaced and still knocking then there is obviously a pressure problem somewhere.

 

However, at 104K miles, a proper head overhaul would not be un reasonable at the least.

 

I get tired of seeing posts criticising garages who are obviously trying to help the customer save money. The only mistake they make in these instances is trying to help the consumer out by cutting a few corners which can work out but invariably backfires. Consequently they are the ones chastised.

 

Conniff, I'm very surprised at your last post to this, so what would you recommend?

[Conniff]

I have always been about saving the customer money and my first course of action would have been to check the oil pressure. A 15 minute job that can tell so much. I don't think that going for a cam and hydraulic follower change in the first instance is helping the customer (as proven here) save money.

It could just have easily been the strainer or the pump itself, and then we are talking a (usually), cheaper bottom end dismantle and not top end.

 

Unless you have owned a car from new, you can never be sure if oil changes have been done on time or have been missed, or if cheap oil has been used leading to over saturation of the suspension chemicals and a reduced flow through the strainer.

 

Of course, even if the bottom end was the cause, cleaning the strainer and even changing the pump may not cure the top end rattle, the damage could already have been done.

 

My first examination of the top end would be a check on the tappet spin, lack of, as you know, is a good indication of carbon build up around the tappet and/or lobe wear, and a simple change of the followers would not necessarily cure that. After removal, a seizure check of the hydraulic followers should be an automatic next move. I know they are relatively cheap, but rarely are a complete set required.

 

Tappet rattle for a few seconds after first starting is also a good indicator of other engine wear allowing the oil to drain back from the head galleries.

Edited September 21, 2009 by Conniff

[heliosuk]

Thanks for the reply, Conniff is spot on with his remarks. I get a bit upset with people having a go at garages who frankly cannot afford to employ people like me and him. However that is a seperate issue.

 

In getting back to the issue concerned, conniff is spot on. As I supposed earlier and have reiterated, low oil pressure causes this which can be caused by many things as described by coniff. It's hard to give a fix to all of this but I still stand in saying is not unusual at this mileage and frankly cost of rectification does not justify repair costs. In fact use as is or sell.

 

It's not a basket case but you have to look at the economics.

 

As a matter of interest, when hot does it do the same thing?

[Debtworry]

Thanks for the replies.

 

Not sure if the garage used a stethoscope, i left the car with them then get a call to say they have removed the rocker cover and can see that the camshaft has worn.

 

I was thinking oil pressure maybe a blockage? As it will only knock briefly when hot or cold, but it doesn't always knock just now & then.

 

I dont mind the work they have done, i just cant afford anymore work to be done, and now the car is making a rumbling noise as if the exhaust is blowing, not sure if this is related to the knock or not, but i haven't investigated.