Hey team,

I am going to visit a Skoda Octavia Estate MK3.5 (2018 plate) tomorrow that (potentially) had a failed timing belt.

I asked the owner what happened and he mentioned that it was ripping or making noises so he had it replaced. He maintains that it didn't actually snap or completely fail, but didn't have much life left in it.

The owner has sent across invoices and service history.

I can see one of the invoices is for "Diagnosing potential faults from timing belt failure, s&f new timing kit", as part of this invoice there is a new timing belt, water pump, and injector seals. And a compression test was done.

Cylinder 1 - 20 Bar (290 psi)

Cylinder 2 - 20 Bar (290 psi)

Cylinder 3 - 17 Bar (247 psi)

Cylinder 4 - 19 Bar (276 psi)

"Test was performed on a cold engine once timing had been rectified, and visual inspection of roller rockers and valve stems revealed no obvious faults"

To me, compression on cylinder 3 seems a bit low. It is less than 10% variance compared to the others. I tried to google the compression required for the 1.6 TDi and I think I found a compression ratio of 16.2 which is around 238psi (16.4 Bar).

Apart from this the car seems in good nick, has been serviced regularly, and has new rear brake discs/ pads. It also had a major service at 93,000 miles by a Skoda garage, change of oil, fuel/ air/ oil filters, and brake fluid change.

The car is now at 94,000 miles.

I guess my question to you guys, is, are there any specific questions you'd recommend I ask the owner, or any general car-buying advice you have for me? Does something seem suspect here, with the low compression on cylinder 3, could there have been some damage to valves with a timing belt failure, that results in lower compression? Or is the lower compression within the realms of factory tolerances?

Hello, welcome to the forum. Was this cambelt incident recent - and is this a private sale?

I'd suggest extreme caution - I think the low compression in #3 does indicate a possible problem with valves. Not entirely happy with #4 either.  

Hi Warrior193, thank you for the welcome

 

This is a private sale.

 

Cambelt incident was at 89,792 mileage, invoice dated 16 February 2023. 

 

Major skoda service carried out at 93,936 miles on 04 October 2023. 

 

The car is being sold now at around 94,500 miles.

 

These are the private sellers exact words "It didn't completely snap. We've changed it in time. But the old one didn't have much life in it", vs the invoice labour description of "Diagnosing potential faults from timing belt failure, s&f new timing kit" completed by JBM Performance in Sheffield. 

 

I feel like something isn't quite right.

I agree with you, I suspect owner is seeing or feeling something worrying and has decided to unload it. That TDI has also not really covered sufficient mileage since the incident to rule out possible DPF issues. 

My tuppence worth.

 

1. If it's a private sale, the owners words are next to useless. If he was misleading you, you'd need to prove it. That said, he seems very open. If I were selling the car I'd just have simply said it had a belt change and leave it at that and nobody would have any reason to question it.  What benefit is in telling a potiential buyer that there were strange noises etc?  

 

2.  You go to the expense of changing the timing belt. If it was a diesel ( you mention 1.6tdi elsewhere )  then water pump really would have benefitted from being changed at the same time. Was that done?

 

3. You then service the car at a main dealer - not many owners would chose that option at 93k!

 

Sounds like this owner is being very honest and has looked after the car. 

 

You don't mention previous owners. How many owners has the car had? When did the current owner buy the car?  What I find strange is the owner forks out on a timing belt, he forks out on a main dealer service, the car has new rear discs and pads so why has he decided to sell the car?

 

 

 

 

Edited 7 December, 20232 yr by kodiaqsportline

It seems reasonable to me, its an interference engine and the outcome of belt failure is bent valves on all cylinders and zero compression, its binary, low compression is like saying someone is half a virgin!

 

Another it was the auxiliary drive belt that failed and while doing so ripped into the timing belt cover which in turn frayed the edge of the timing belt which was replaced together with the water pump etc.

 

I would go by my own judgement of how the engine felt, if I had any doubts I would do my own compression test, I do not believe a word the motor trade says especially when they are being asked to write it down by the person paying their bill.

2 hours ago, kodiaqsportline said:

When did the current owner buy the car?  What I find strange is the owner forks out on a timing belt, he forks out on a main dealer service, the car has new rear discs and pads so why has he decided to sell the car?

 

That is a pertinent question but only if looked at in relation to his previous vehicle ownership.

On 04/12/2023 at 14:41, Major-Frodo said:

Test was performed on a cold engine once timing had been rectified

 

Those are the words that would compound any doubts that I have.