Polo Classic oil leaks, mechanic blames sump blowby (2000 model 1.6 engine)

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lukezim
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Car Model: 2000 Polo Classic

Polo Classic oil leaks, mechanic blames sump blowby (2000 model 1.6 engine)

Post by lukezim »

Hello everyone

I have been the owner of a 2000 Polo Classic for almost 2 years now and have had continual oil leak issues over the past year or so.

I started getting major oil leakage around March this year. I got the cam and crankcase seals replaced as well as the tappet cover and the leaks stopped for a while.

After a month or so, I started noticing oil leaks once again, but not as serious as the first time round. I eventually took it back to the same mechanic who kindly enough inspected it again for free and replaced the top seal, and did some resealing of the tappet cover. He suggested that it was possible the seals kept blowing due to blow-by.

Unfortunately, the car was still leaking after this. So I took in for a third time and they once again inspected for free and told me the top seal had again blown. He said he could do it again but it would just keep blowing due to the blow-by. I asked about a compression test, but was told that because the pressure was coming from the sump, it wouldn't be picked up in a standard compression test. Does this sound plausible?

I am intending to buy a more reliable car soon and was hoping to at least sort out the oil leaks before selling but seems it is a losing battle and the only solution is an engine overhaul which I don't intend to do.

I just wanted to ask here what people thought about the sump pressure explanation for the issues with the seals? I've had no reason to mistrust this mechanic before and their place is certainly well regarded based on their reviews. I just can't find much information on the issue of sump compression.

My only reason for suspicion is that I have discussed the issue of selling the car with him from earlier on in the year and I know he would be willing to buy it off me. So I just wonder if he could be making out that the engine basically needs to be replaced/overhauled, in the hope that I would sell him the car for cheap?

Sorry if I am being too cynical but would appreciate any thoughts form someone with more knowledge then me. For what it's worth, the car is on 197 000 km mileage.
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Jetta2
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Re: Polo Classic oil leaks, mechanic blames sump blowby (2000 model 1.6 engine)

Post by Jetta2 »

Based on your experience with this "mechanic", if I was you, I would take the car to someone who actually knows what they are doing.

A normal compression test will tell if one or more cylinders are down on compression and that would lead to sump compression due to rings being worn.
That test will take about 10 minutes to do and if he cannot/will not do that, take the car somewhere else.

By top seal you mean head gasket? If so and he has replaced it twice, he definately does not know what he is doing.
Where are you based so that we can recommend a decent proper mechainc to take care of your car.
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lukezim
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Car Model: 2000 Polo Classic

Re: Polo Classic oil leaks, mechanic blames sump blowby (2000 model 1.6 engine)

Post by lukezim »

Wow that is interesting. I'm not too sure what he meant by top seal and he never invoiced/charged me for it so I don't have it written down either.

Dubious comments around the compression test aside, is it possible that blowby could be causing such issues?

I'm based in Cape Town. A good mechanic in Southern Suburbs would be ideal as that is where I work and live.
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Re: Polo Classic oil leaks, mechanic blames sump blowby (2000 model 1.6 engine)

Post by missioner »

Sump compression, cylinder blow by, crank case pressure are names for the same thing.

Combustion gases are leaking past the piston rings and then exiting the motor via the crankcase ventilation system. Continuous oil leaks, excessive oil consumption, smoke from the exhaust when starting, driving and acceleration are all symptoms of this.

Sadly the only good solution is to rebuild the engine.

The one way to see how bad it is, open the oil cap when the engine is idling and warm, it should not have any smoke coming out and also have a slight movement of gas in and out. If there is "smoke" (oil vapours) leaving the motor with some pressure, that is a sign of a less than healthy engine.

This is not true for all engines as designs differ and emissions systems can also play a role, but you can use this as a general guide to quickly assess engine health.
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Re: Polo Classic oil leaks, mechanic blames sump blowby (2000 model 1.6 engine)

Post by missioner »

Jetta2 wrote:Based on your experience with this "mechanic", if I was you, I would take the car to someone who actually knows what they are doing.

A normal compression test will tell if one or more cylinders are down on compression and that would lead to sump compression due to rings being worn.
That test will take about 10 minutes to do and if he cannot/will not do that, take the car somewhere else.

By top seal you mean head gasket? If so and he has replaced it twice, he definately does not know what he is doing.
Where are you based so that we can recommend a decent proper mechainc to take care of your car.
A compression test combined with a cylinder leakage test will accurately determine the condition of the engine internals.
'87 Golf 1 Olde Skewl OEM+
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