04 Renault Espace 2.2dci - Low Compression - any ideas? - xena_wales

Hiya, my bf's Espace has been running a bit rough for a couple of weeks now, sounds bad at idle and low power at low revs.

He took it into a garage yesterday and they performed a leak off test and compression test, with the diagnosis that it has low compression (150 cyl 4, 250 cyl 2+3 and 300 cyl 1).

They suggested an engine rebuild??!

Am possibly grasping at straws here, but is there any possibility it could be something less serious? I've heard of sticking piston rings - might that give similar symptoms?

Why an engine rebuild? - what's the root cause of low compression - is it cylinder head gasket, or worn piston rings, and how to tell which? It just seems a bit of a generic diagnosis and am wondering if it's possible to narrow it down a bit?

Many thanks for any replies.

04 Renault Espace 2.2dci - Low Compression - any ideas? - Oli rag

Has there been any loss of coolant or contamination of the oil (mayonnaise) prior to the rough runnning problem.

Has the car done a huge mileage?

Has it been regularly serviced, no missed oil changes?

Could be just a head gasket problem, however sounds unlikely with those readings.

04 Renault Espace 2.2dci - Low Compression - any ideas? - xena_wales

Haven't seen the car since the diagnosis (bf still using it) so will check water and oil in the light tomorrow morning.

Mileage = 100k, servicing, not sure, he hasnt had it for that long so would need to ask him the history.

Thanks for the reply, that's just the kind of advice I'm after - what other things I need to check in order to get a clearer picture of the problem :)

Will update ASAP.

04 Renault Espace 2.2dci - Low Compression - any ideas? - Fernando P

I am sceptical about the low compression diagnosis but accept that anything is possible. At 100k the engine should be running efficiently and can be expected to reach >200k if it has been properly and frequently serviced. The oil required is synthetic 5W40 (diesel) and should be changed at <9k / annually. If this has not been done then beware. Does the engine start up easily and without much smoke being emitted? Does it pull away as it should? When was the cam belt last changed? The inlet manifold is "plastic" and some have been known to warp resulting in rough running. But the manifold can be checked out. Consideration of an engine rebuild should be way down your check list at the moment.

04 Renault Espace 2.2dci - Low Compression - any ideas? - xena_wales

I'm sure we were told it's been regularly serviced and cam belt done or it would've rung alarm bells when we bought it. I'll look through the book later.

It starts absolutely fine and no smoke that I've noticed. Just sounds a bit tractor-like. As long as you keep the revs up it drives pretty much ok, but stuff like moving off in 1st gear is difficult if you allow the revs to drop too much as it bogs down really bad.

Will double check service history and maybe take a vid of it starting and running and post back. Many thanks!

04 Renault Espace 2.2dci - Low Compression - any ideas? - unthrottled

If the rings are not sealing properly, then the amount of blowby must be pretty horrendous. Is there any sign of the dipstick being forced out of its tube or oil around the end of the dipstick tube?

Poor low speed running is consistent with low compression. Unfortunately, head gasket failure is the least expensive possibility with low compression.

04 Renault Espace 2.2dci - Low Compression - any ideas? - Fernando P

Regarding (diesel) compression testing, all the cylinders should have similar pressures. A material difference is an indication of a fault. Where the cylinders are worn, low compression, which gradually increases as the engine is turned, is the normal pattern. Low compression at the start of the testing, which does not build up, indicates leaking valves or a failed head gasket. If two adjacent cylinders read low, this is an indication that the head gasket has failed between them. Another issue to consider is that the Exhaust Gas Recirculation (EGR) valve of the 2.2Dci engine needs to be cleaned out every 18-24 months especially if shorts runs are regular. Typical symptoms of the EGR valve and surrounding area being sooted up are sluggish pulling away after stopping, accompanied by a big puff of black smoke, as power is applied and the revs are increased. Is that description familiar? I think that could be first on my action list from your report. There is also the issue of possible mis-fuelling to consider if the engine is not running smoothly!

 

Value my car