Smoking VR

[Will 0]

Just been reading some of the threads on reasons for smoking VR6 engines. Had mine for over a year now and it has been a bit smokey on occasion from day one but it's getting worse and think I'm going to tackle the problem in the next couple of weeks.

Thing is, the car doesn't smoke on idle, mostly hard acceleration but every now and then I see random plumes of smoke in the mirror when just driving along normally - then nothing again for ages.

It does drink a lot of oil and 1 or 2 of the spark plugs are wet but the water never needs topping up.

Is there anyway I can tell if it's valve seals or something more worrying like piston rings..?

[sciroccotune 0]

Free wheel in gear down a hill then boot it at the bottom, if you see smoke its the rings if not its the seals.

 

Well something like that ill check with my dad tomorrow for which way round it works..

 

:-D

[RW1 0]

Thing is, the car doesn't smoke on idle, mostly hard acceleration but every now and then I see random plumes of smoke in the mirror when just driving along normally - then nothing again for ages.

 

More likely to be the rings are getting worn with this. Start up puff is usually the valve stem seals.

 

 

"It does drink a lot of oil and 1 or 2 of the spark plugs are wet "

 

If its No. 1 & 6 may have broken rings, quite common, the cylinders on the back off side corner and the front nearside corner. There is a thread back 8 weeks ago on this. basically need to do some tests such as compression to determine.

[Kevin Bacon 5]

What usually happens is bores 1 and 6 get scratched as they run the hottest....they have cooling jackets half the size of cylinders 2, 3, 4 & 5. It's a design fault. Due to the 2.9 making more power and torque, and therefore more heat than the 2.8, the former doesn't exhibit this problem half as much...not to mention working in a bigger engine bay in the MK3 golf, passat etc.

[Will 0]

Right thanks, doesn't sound too promising then! I'll get the compression tester out tomorrow morning...

[RW1 0]

Sorree for the bad news but better prepared for the possibility than hit bluntly later.

[dazzyvr6 0]

what grade oil do you use?how many miles has your car done and how much oil does it use?

[Will 0]

what grade oil do you use?how many miles has your car done and how much oil does it use?

 

I use 10/40 oil (the silver quantum or magnetec) and the car's got 98k on the clock. Not exactly sure about oil comsumption as it seems a bit random but i'd estimate 1/2 a litre between fill ups.

 

Just did a compression test with the following results:-

Cyl 1 - 159PSI Cyl 2 - 167PSI Cyl 3 - 167PSI

Cyl 4 - 180PSI Cyl 5 - 181PSI Cyl 6 - 171PSI

 

Also plugs look pretty oily (see pic). They've been in less than a year - the NGK on six is due the the Bosch one packing up about 6 months ago.

 

Not sure if this sheds any more light on the situation. Happy to do a recon job on the head and was going to do the chain soon anyway but not keen on a full overhaul. Might be cheaper to look out for a engine with a few less miles then flog mine on the cheap...?

 

Thanks again for the help.

[Dutch24V 0]

You should really be using the NGK plugs all round btw as they're much better than anything else in a VR and will last longer.

 

I'm no expert but think you should try a thicker oil to start with and see how it goes from there. 10/40 is too thin for a VR. I use 15/40 and might change to 20/40 soon.

 

Those plugs look alright to me for 6 months use too, except 6 of course. My plug 6 is getting more fouled up than that every couple of months so don't think you have too much to worry about for a while.

 

Also, those compression readings aren't to bad either for a 10 year old engine (from my limited knowledge anyway!), but I might be corrected shortly be someone with more no-how! My cyl. 6 has a reading of 6 BAR - not sure what that is in PSI but alot lower than any of your readings.

 

Anyhow, change the plugs to NGK all round, put thicker oil in and go from there. I don't think you have too much to worry about for a while yet!

 

 

Dutch

[RW1 0]

Are you sure they are oily and it's not running too rich?

 

Agree the 1 to 5 plugs are the wrong type. And the VR6 is designed for one plug only in mind, the NGK. Spark uses the insulator as well as the gap to bridge across the plug.

 

Photos for me not too clear, the black looks a little dull for oil. May just be the photos. Obviuosly as stated, it is using oil. Check ignition lead resistance is 5k to 7k ohm resistance just to be sure there are no problems getting the spark in the cylinders.

 

10w40 to 15w40 in the UK won't make that much difference if it's oil getting into the cylinders.

[dr_mat 0]

The other plugs look like they're just sooty, not oily.

[Kevin Bacon 5]

Crusty deposits is burnt on oil. Plugs that black also suggest over fuelling and lots of short stop/start journeys, I'd get it on VAG-COM to make sure none of the sensors are out. All 6 should be light brown around the centre electrode and mid grey on the ground leads.

 

The 2.9 is a curious engine. Cylinder number 1 on mine gets a little oiled up after a few K and mine's on 120 thou, but it was dynod 2 weeks ago and developed 199bhp and 190 torque, so a rebuild simply isn't justified at the moment and I'm living with the occasional puff. It's a 10 year old engine used daily and is totally reliable, so I can forgive it a little oil useage here and there.

 

I would recommend a remote oil cooler and a thorough overhaul of the water cooling components to make sure it's running as cool as possible. I have a remote cooler on mine and it rarely gets over 100 degrees on the MFA. The cooler the oil is, the more stable it's viscosity will be.

 

There's no denying the VR6 is a fabulous engine when it's running right, so hang in there and try and sort it if you can afford it.