Hoppeltest failed? Next steps: Compression or what now?

Hello,

I urgently need some advice:

I test drove a Ford Galaxy (1.9L TDI AFN, 81kW, manufactured in 1999, 150,000 km) and performed a bounce test.
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.
done.
'In the first gear, I measured 20 jerks. Three cylinders showed relatively consistent readings with an average of 7.7 seconds (average values for each cylinder were 8.0, 7.9, and 7.25 seconds), while one cylinder had a reading of 5.36 seconds (ranging from 4.97 to 5.86 seconds), resulting in a ratio of 1.44/1 between the three cylinders and the one cylinder.'
Since up to 33% seems to be acceptable, it suggests that something might be wrong.
The paper test also shows some wear, but not much more than my colleague's A3 with 80,000 km (approximately 50,000 miles).
The airflow test revealed approximately a 5% reduction in performance.
Otherwise, the car was actually okay.
The turbo kicks in at approximately 1600 RPM and pulls smoothly all the way up to over 4000 RPM without any dips.
With a warm engine and without fully accelerating while idling, there is no smoke visible from the exhaust.
The engine is externally oil-free and has some minor saltwater stains, so it hasn't been cleaned. The timing belt was replaced at 83,000 km, and the mass airflow sensor (MAF) was replaced approximately 10,000 km ago.

Apart from the difference of one cylinder during the compression test, I would like to buy this car.
Can you help me interpret the test results?
What can be checked next to find out what's causing the problem, or what needs to be done/implemented?

Thank you in advance for your help!!!
Best regards, Roland.

RoBro wrote:

Apart from the difference of one cylinder in the hop test, I would like to buy the car. Can you help me interpret the test results? What can be checked next to find out what's causing the problem, or what can/must be done?

Definitely request a proper compression test before making a purchase. If the values are still within the acceptable range, then this result is valid (please post it here!!).
-> While the Hopel test can provide some indications regarding compression, it cannot produce an "official" result.

If the compression test is refused, my advice would be: stay away from that car...

The compression test is likely fine, as I can't imagine that all the values were determined correctly. And as Ulf already said: do a compression test, and then decide!

Hi,

If the compression test is good (meaning the compression is within the acceptable range), how should I interpret the results of the 'Hoppeltest,' which seems to indicate a clear problem?

If the compression is bad (how much less can a cylinder have, or is there only a minimum value?), does that mean you should just give up on it, or can you determine the cause with a reasonable amount of effort?
If it's due to worn cylinder liners, there's not much more that can be done.
Could there be a problem with the valves, the injectors, or the glow plugs?

Best regards, Roland.

Another question (regarding the previous ones).
What is a reasonable price for a compression test on an AFN engine?
Best regards, Roland.

RoBro wrote:

If the compression test is positive (meaning the compression is good), how should I interpret the rather clear result of the "Hoppeltest"?

The "impractical" very low speed and pressure levels used in the "Hoppeltest" can create different impressions than those that are relevant when the engine is actually in operation.

I don't have the target values and wear limits readily available -> should I use the search function?

Is a compression test typically performed by cranking the engine with the starter?
How many revolutions per minute does it normally run at?
Regards,
Roland.

During a compression test, isn't the engine cranked using the starter, or?
How many revolutions per minute does it normally run at?
Regards,
Roland

Even that is again a case for the search function!

I've been searching, and I found that it takes approximately 300 RPM to start it up, so I'm guessing around 400 RPM. Is that correct?


How many fewer cylinders are allowed, or is there only a minimum value?

I only found the minimum values (wear limits), but nothing about how uneven they can be.
If the minimum requirement is 24, and 3 cylinders each have 32, and one has 26, then all cylinders are still above the wear limit, but does it matter that one has significantly fewer?

Regards,
Roland.
P.S.:
Perhaps I'm not entering the right search terms. As a complete novice, you don't always know which technical terms you need to search for...
I hope you can still help me.

Okay, I just got a price for the compression test, and it's 30 euros (isn't that a bit low? I'm obviously happy, but I was expecting more).
When asked what can be checked if it fails, the response was that you can pour a cleaning agent into the tank and drive a full tank of fuel to clean the valves.
Unfortunately, I can't drive the deregistered car, which I don't even own, for 800 km until the tank is empty .
What do you think the next step should be after the compression measurement?
Regards,
Roland.

30 euros sounds like a good price!

Regarding the fuel additive, I wouldn't put too much faith in it. We've had tests here before with diesel additives, and the results showed it only improved performance by a small amount, maybe 1-2 times better.

I believe that the only real solution is either replacing the parts or proper rework.

hmm...
Swapping parts in a car that doesn't belong to me...
It would be great if it were possible to find out, using reasonably affordable methods (like the €30 mentioned), what's causing the problem and what the approximate costs will be.
I can't just say, 'Let's have the compression checked and then we'll see,' because it's not my car, and it's not registered. And I don't think the seller would be happy if I kept picking up the car every day to take it for a new test, or even left it at a workshop.
'In that case, he'd rather sell it to someone else, even if it takes a week longer.'

And even buying something and then repairing it isn't ideal, because in that case, I wouldn't have needed to do that 'bouncy test' in the first place.

Regards,
Roland.
P.S.:
I also searched for information about compression, and found a lot of interesting things, but nothing about further testing options.

You're probably getting way too worked up about this! Either the car suits you and you like it, and you accept the risk of needing repairs, or you let it go. The seller certainly won't be thrilled, but if they have nothing to hide, they'll understand. Is the car being sold by a private individual or a dealer? If it's a dealer, you're actually on the safe side. In that case, they should be able to prove that everything was in order at the time of delivery within the first six months. On the other hand, even with a private purchase and your intense focus on the engine, you might overlook some other important things.

Okay, if it makes you feel better, get a compression test done, post the results here, and then we can see what to do next. Complaining about 'what if' and 'but what if not' and all that won't help anyone. No one here can read minds! And without facts, it's difficult to make a proper diagnosis remotely!

Okay, I'm getting a compression test done tomorrow.

If the compression test is good, then the car is practically as good as bought.

If the seller (a private individual) doesn't want to do it (I'm happy to pay for it myself), or if the compression test fails, then the car is probably not for me.
The mechanic just said on the phone that if the compression is bad and there's no visible leakage (e.g., at the glow plugs or injectors), then the cylinder head definitely needs to be removed in order to make a further diagnosis.
'I'd rather look for a different car, because I'm not interested in spending a few thousand euros on repairs for a used car that only costs 9,000 euros.'

I was hoping there might be more 'insider tips' here on how to check other things with simple methods that are related to this.
So, if anyone still has any ideas...

So, for example, I'm very glad I found this 'Hoppeltest' (bouncing test) here, otherwise I would have bought the car yesterday. Now I'm going to do a compression test, which I wouldn't have done otherwise.

I will definitely post a comparison of the compression measurement and the Hoppel test later.

Regards,
Roland.

What other insider tips are there? If the 'hop test' didn't go as you hoped, a compression test will provide clarity! That's it!

'If the compression test is negative, the cylinder head might need to be removed. However, it's also possible to measure the crankcase pressure, although that won't give a definitive answer either. Removing the cylinder head isn't the problem. If the car has been reasonably well maintained, the wear on the cylinder walls should be within acceptable limits, and the oil scraper and piston rings should be in good condition. If that's the case, the problem might be the valves, which shouldn't be a major issue or cost a lot to fix. Of course, if you rely on a workshop, it will naturally be more expensive. But as I said, without values, there's no diagnosis, and any diagnosis is only tentative. Please don't forget to inspect other things during your engine test!'

Does it include a complete service history booklet?

The service booklet was maintained by a Ford dealership until 2002, and then by ATU in 2003 and 2004, although I had already been to ATU before.

Air is escaping from the oil filler neck, noticeably, but not in a violent rush. I'd be interested to hear your opinion on my theory regarding this.

/viewtopic.php?t=68&highlight=roland

I might need to turn off the KGE (Kondensgasentfeuchter) and repeat the paper test.

Well, apparently there's no other way to check the valves than to remove the cylinder head .
And as an electrician, I unfortunately need a workshop to handle something like that.
Do you think you could give me a VERY ROUGH estimate of what it might cost to have the cylinder head removed, the valves/lifters tested, and then reassembled?
Best regards, Roland.