Loss of power at low revs

**dangun82** · 30-07-2008,02:17 PM

Hi everyone,

Yet another newbie question I think, so please take it easy.

I own a VW Golf TDI 100bhp Mk4. Recently I have been experiencing a problem where under low revs I lose power when I put my foot down. It happens in all gears apart from 1st (or at least I have never noticed it).

I can be quite happily driving along in fifth gear about 55-60mph just under 2000rpm. If I ever want to pick up speed quickly to overtake or something I usually put my foot down in the same gear and let the turbo do the work. But now, when I put my foot down the revs will suddenly shoot up to above 2300rpm - 2500 and the turbo would kick in but the revs would then fall to below 2000. The car will then again steadily pick up speed as I would normally expect it to.

One thing to note is that when the revs drop I tested this with my foot on the accelerator and taking the foot off and it didn't seem to matter.

Any ideas what it could be? Any replies greatly appreciated.

Cheers.

**dangun82** · 01-08-2008,12:23 PM

Hi again,

Just to update on things, I have been to a VAG specialist and drove my car and was able to recreate the problem. He seems to think that its my clutch slipping and wants to charge me over £300 for a new clutch.

a) Do you think that clutch slipping is actually the problem? Could it be something else?

b) If it is the clutch, does that price sound right?

**James H** · 01-08-2008,12:53 PM

Hi - a slipping clutch has quite distinctive symptoms and the only thing I can think of that does anything similar is a loss of traction at the road surface - so it's not a difficult diagnosis for the garage to make. Also, your description of the revs shooting up to 2300 or more without a corresponding increase in road speed, and then falling back down again is perfectly consistent with a clutch slipping under the initial torque of acceleration, and then biting again as the car gets moving.

I suspect your garage man is right as to the problem. Can't tell you anything about the cost quoted to rectify, but it doesn't sound that bad to me. You can get the cost of the clutch kit from loads of places (GSFcarparts is one).

Hope this helps,

kind regards,

James.

**dangun82** · 01-08-2008,01:51 PM

Thanks for that James. I will check out some other garages and the Internet for pricing.

Really appreciate your help

**paul b** · 01-08-2008,04:27 PM

As stated, it is quite possibly the clutch.

I assume the specialist ran a fault code read ? And that no fault codes occurred ?

Paul

**dangun82** · 01-08-2008,04:34 PM

No he didn't take a ??vagcom?? read, he just drove it and instantly came to the conclusion that it was the clutch.

I didn't think there would have been any point in looking at that anyway as the engine light didn't come on

**paul b** · 01-08-2008,04:50 PM

Originally Posted by dangun82

No he didn't take a ??vagcom?? read, he just drove it and instantly came to the conclusion that it was the clutch.

I didn't think there would have been any point in looking at that anyway as the engine light didn't come on

Fault codes that are stored don't automatically put a warning light on. As a specialist, I would have thought he would have done that straight away, it takes less than 5 minutes to do.

All evidence suggests the clutch is the culprit, but you could have a fault code read done which costs peanuts, because if you get the car back and its not cured, and you have fault codes, then it is £300 down the drain. Better to be safe than sorry isn't it ?

Paul

**Crasher** · 01-08-2008,05:26 PM

If the clutch is slipping it will be due to the dual mass flywheel failing and that is another £300 to £460 (from VW) on top of the £300. It is no use just doing the clutch. When this loss of power happens, do the revs increase but the vehicle speed stay the same?

**dangun82** · 02-08-2008,01:35 PM

Thanks Paul_b I will get that checked out. It is better to be safe than sorry.

Crasher - When the loss of power happens the revs just shoot up with no massive difference to speed. Then they come back down until the clutch catches again I guess and then I speed up again normally. I'm really not going to be too happy if the flywheel is bust as well, I've only had this car a year (although it is an 02 plate).

**Crasher** · 02-08-2008,06:17 PM

Yes that is classic clutch slip and it will be the flywheel unless there is some oil contamination from an oil leak or the car has covered a lot of miles or been driven by a numpty. If it has been driven badly, i.e. been slipped a lot due to poor driving style, the heat generated will have damaged the DMF and a high mileage car would have a worn DMF anyway. Even if it doesn’t need a flywheel now, there is no way I would do a clutch on a PD and not do the DMF, if the customer insisted I just did a clutch if the DMF appeared OK I would make them sign a disclaimer excluding me from any liability WHEN the DMF fails. I have done them on much newer cars than an 02 and it isn’t a problem confined to VAG, the LUK manufactured DMF is used by many different manufacturers such as BMW, Merc, GM etc and they fail on those as well.