Mk5 2.0gti cut out and loss of compression - advice
Mk5 2.0gti cut out and loss of compression - advice
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joeyb01

Original Poster:

1 posts

Yesterday (17:13)
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Hi all.

so today I went to view a mk5 2.0 gti 2006 with 97,900 with my frienI’m qualified to level 3 IMI standards in vehicle repair and he had just had his old corsa d VXR blow up on him yesterday so he needed something decent. I’ve always had a soft spot for golfs and bought myself a mk6 2.0 gt a few months ago, so recommended a golf to him.

we went to view it and he loved it straight away. I got my topdon plugged in whilst he had a look around. The engine started fine and didn’t miss a beat, he took it for a drive with no issues. My topdon finished its scan with historic codes only.

there was only a few things I picked up on; heavy corrosion subframe; typical wing rust and the gearbox caked in old engine oil. At this point he was handing the money over as he wanted it. I asked when the timing belt had last been replaced but seller said he didn’t know, and upon review of the service book it showed it hadn’t been done since 2015.

Halfway home, the STOP! Oil pressure warning light came on, at which point we were on the motorway. As the engine sounded ok, I advised to get it off the motorway onto services and go from there, although my tools were all at home including my oil pressure test kit.

we didn’t make it to any services. The car started making what I can only describe as a screeching sound, it then cut out and we had to pull onto hard shoulder. When we tried to restart it, it sounded like the engine had lost compression. In the end we got it recovered home and in now going to have to take it all apart.

there was no smoke, no loss of power (just cut out) no bangs and no loss of either oil nor coolant.

The timing belt seems to still be under tension and intact.

The following codes are present:

P0299 - Turbo Under Boost
P3138 IMRC
P000A Camshaft Pos Slow Response
P0333 Knock Sensor Circ High Input
P0100 Fuel volume regulator circuit open

The engine then did start but runs very very rough with no throttle input, then cuts out and goes back to sounding like no compression.

I don't want to spend too much time on it but would like some idea's what could've happened

thank you all

Doesitdrive

1,361 posts

8 months

Yesterday (17:21)
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Had the complete opposite with the 2007 101k one I bought blind for 2k around 4 years ago, been excellent but had care, as well as another hard 65k.

One issue that caused power loss was leaking air pipes , they are 20 years old now, a smoke test revealed which needed replacing but did them all.
No eml since, no power loss since, no rough running since, might be somewhere to start.

ManicMunky

665 posts

147 months

Yesterday (20:51)
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Not being funny, but there's some very basic troubleshooting here that your "qualified" friend should know how to do.

si_xsi

1,309 posts

222 months

Yesterday (22:45)
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Oh dear sounds like a nightmare. Oil pick up pipe would be my guess, they can get clogged up, then oil starvation and lack of pressure.

Dr G

15,900 posts

269 months

Could be one, multiple, or snowballing faults there.

Oil pickup, timing chain stretch, boost leaks...

That's one where you'd start with the basics and address/eliminate as you go. It's an old car, usually modified, and usually poorly maintained so I wouldn't be surprised to learn that a failure had unearthed other weaknesses.