Previous owner flushed engine every year...bad idea ??

bishbosh89

bishbosh89

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Hi

I bought an old b5 1.8t with FSH last week. I was wondering on the merits of engine flushes at garages.

Normally, I wouldn't touch them with a barge pole, in fear of dislodging ten tonne of crap, but I notice the previous owner of ten years had his mechanic perform an ' engine flush' every year with his service.

Should I continue with this as the car runs very nicely, or leave it.

I think the guy was very anal, he did the fuel filter and spark plugs every year for gods sake.

Any input would be appreciated,

Jamie
 
On a regularly serviced engine no problemo , but on a poorly serviced or unknown servicing , no.

Personally I'd just change the oil every 6 months.

There's no guarantee the garage actually performed a flush , spark plug and fuel filter changes as they knew it would function perfectlying without.
 
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I've flushed seriously grotted up engines before without any issues.

Personally, i change my engine oil every 5k, but dont bother flushing it. If i buy a new car, i'll tend to do 3 oil changes in quick succession, perhaps 200miles apart, as the fresh oil tends to dissolve all to crud into it anyway and that acts as a gentle flush.
 
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audi upgrades
Thanks for the reply. That makes sense to me, I never trust a garage has actually done what they say they have. Always best to do these things your self hey.

Nice motor by the way

Jamie
 
aragorn said:
I've flushed seriously grotted up engines before without any issues.

Personally, i change my engine oil every 5k, but dont bother flushing it. If i buy a new car, i'll tend to do 3 oil changes in quick succession, perhaps 200miles apart, as the fresh oil tends to dissolve all to crud into it anyway and that acts as a gentle flush.
Click to expand...


I don't like the 1st part but agree with 2nd .
 
Thanks Aragorn, another good recommendation, my mind is at ease, I'll just do 5-6 k oil changes.

Thanks all
 
Gazwould said:
I don't like the 1st part but agree with 2nd .
Click to expand...

Its certainly not ideal, but sometimes theres little other option.

I bought a cheap MOT failure A4 1.8T so i could have its engine for my track car, sight unseen off ebay for £250, and had it delivered. When it arrived, the engine sounded like a bag of spanners and the lifters were all hammering away. I drained the oil out and it came out literally like treacle, dripping out in big clumps. Nothing to lose at that point, so i filled it with 50:50 mix of engine oil and diesel fuel, started it and ran it for 10 minutes at 1800rpm. After about 7-8minutes, the engine quietened down and you could hear the lifters closing up and starting to work properly.

After the 10 minutes, i drained the mixture out and refilled with the same again and repeated the process. This time with 30seconds the engine had quietened right down and sounded almost healthy. Drained after 10minutes and refilled with normal engine oil and ran it up and it sounded more or less perfect.

After all that it ran fine, but at hot idle the oil pressure was a little bit low, so when i pulled the engine out the A4 i whipped the sump off and replaced the oil pump for a "new-but-used" one i got off ebay for a tenner. I also cleaned the sump out which was still a bit manky, but the pickup pipe was pretty clear after all the flushing. The engine as so far managed a 4 hour track day without blowing up!
 
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Very interesting post Aragorn, never thought of using diesel in such a way. Defiantly was worth it in your case. Not sure I'd do it on a daily driver but very clever none the less!

I'll see what the oil looks like when I drain it, thanks for your comments certainly food for thought.

Jamie
 
I've used this trick on my old Zetor 6748 tractor fuel pump governor.
It was rusted up and full of treacle-like hypoid oil.

Diesel is a light oil, so helps thin out the crud and wash it whilst still lubricating.
I wouldn't do it for too long though - and remember it is more volatile than 20-50!

I've also used a form of Kerosene to do the same
 
Yeh, I noticed that most engine flushes are little more than kerosine. Obviously they come in a small 500ml can and your diluting it into 4+ litres of engine oil, but its essentially exactly the same thing.

I refuse to pay a fiver for an engine flush knowing that its just kerosine, but kerosine isnt readily available these days, whereas diesel fuel is very similar and is available everywhere for about £1.20 a litre.

If you want to replicate the off-the-shelf flushes, just pour in half a litre of diesel and run it for 10 minutes like you would with a branded flush.
 
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You can drain some off to prevent overfilling.
If you're not at the very top of the stick I wouldn't worry.

Kero is easy to get if it's your heating fuel - do not use coal as a substitute!
(Although28 sec. Kero is 'gritty' compared to Diesel as it hasn't a lubrosity agent such as is found in a Kero fuel like Jet A1. This has gotten worse due the the 'Low Sulphur' Kero, as the sulphur had a lubrication property too I believe)
 
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Checked my oil level today, and under the cap. Black and filthy oil and the same look under the cap. Defiantly going to try the half litre diesel trick. I'll change the oil and filter with some 15w40 Diesel engine oil mixed with half a litre of diesel.

I'll drain it after 10 minutes and refill with the good stuff.

Results shall be posted on here with pictures next week
 
Interesting thread!

Spoke to a new mechanic a few weeks back and he suggests running some engine flush for about 100 miles prior to replacing my pick up pipe rather than just 10 minutes.

Anybody run engine flush for a significant time (100 miles)?
 
Not sure mate. Wouldn't actually driving the car with the newly dislodged 'bits' pose more of a threat to the engine ? It's lovely to think of cleaning the engine in such an easy way though!
 
This was my concern. I asked him, but he reckoned that just 10 minutes wasn't enough to dislodge much.

I want the pickup pipe cleaning, but as you say don't want to kill it trying to dislodge engine crap!
 
i've heard of folk using ATF added to their engine oil for extra cleaning, but i'm not sure it will really do much.

I wouldnt run the flush in the engine for a long time, though i suspect if you ensured the oil pressure and temperature remained acceptable, there wouldnt be too much issue of running a small amount of diesel in the oil. Some DPF equipped cars can end up with 5-10% diesel in the oil due to the regenerations.
 
Yeh i mean anything more than the 10-15mins suggested.

Like i say, i suspect in reality it wouldnt do much harm, many a faulty diesel engine has ended up with significant dilution of its engine oil with fuel without catastrophic engine damage.

Obviously if you were going to try it, i'd suggest one decent long journey of maybe 20 miles to allow the engine to reach maximum operating temperature, and avoid large throttle openings and high RPM's, then back home and drain it out while still hot and thin.
 
A good middle ground I think, would be a good half an hour idle as opposed to just ten minutes. That's what I shall be doing this week end. I don't want to over do and I think actually driving with the flush in would be just that.

Good to hear so many ideas and opinions, so good to be back on here!
 
Dont leave it idling. You want 1500-1800rpm to make sure it maintains oil pressure.

If its getting regularly serviced you really dont need much, drive around in the car to ensure the engine is fully warmed up (oil temp guage at 80c) then pour in your can of flush or your 3-400ml of diesel, and run it at fast idle for 10minutes, then shut it off and drain immediately. Leave to cool for a bit before putting fresh oil in, you can do the filter etc while your waiting, and make sure you pre-fill the filter with clean engine oil before installing.
 
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Ok mate, I'll do as you say, but why is idling no good, surely the oil is circulating just under less pressure ?
 
The oil pressure falls because less oil is flowing round the engine. Thin oil causes the pressure to drop further, and prolonged idling on very thin, very hot oil especially on a higher mileage engine can allow the pressure to drop danerously low.

My old 1.8T used to start clattering its lifters if you left it idling hot for more than a few minutes. I fitted an oil pressure guage and it would get as low as 8psi at idle, when the Audi specified minimum is something like 18. Lifting the revs to even 1200rpm would bring the pressure back up to 20ish.
 
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Update

I went to change the oil today before the diesel/oil flush and the sump nut will not budge.

It's now rounded off so I'm stuck for now.

Changed filter only, will do until I can get the oil done.

Any suggestions for the sump nut?

If I have the sump replaced I would be able to also change the oil pump and pick up. Correct?

Worried as to why the nut has seized.
 
I don't use the sump plug anymore

R262766-01.jpg
 
Heard about those. In through the dip stick guide?
 
Lovely offer mate, but I'm near North London. Thank you any way.

Ordered an oil extractor pump from ebay.
 
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