Blue smoke, erratic idle (once hot) leading to stalling

[RustyNuts]

Is that a head gasket or piston ring?

 

Obviously the lump is beyond saving either way but i'm just curious which one it is.

 

Thanks

[Fabergé Greggs]

Sounds like a perfectly healthy 2 stroke.

[Squire_Dawson]

Could it be an excessively rich mixture leading to flooding I wonder? What colour are the sparking plugs?

[sierraman]

Piston rings

[r.welfare]

What's the oil consumption?

 

I had a Mazda with buggered piston rings and/or valve stem seals (it smoked a lot at cold start and also shot out smoke/oil droplets when revved warm), that was consuming a litre every 200 miles but the idle was rock steady and it didn't stall.

[AMC Rebel]

Surely worth checking the PCV and associated pipework?  Depends what car - but my old Volvo 240 smoked like a bugger when the PCV was blocked.

[billyboy406v6]

Blocked crankcase breather ?

[RustyNuts]

Hi guys sorry for the long delay replying..

 

It won't be the PCV or breather as i did those on this engine just before it came out of the donor car (that was in 2013.. but its not been used since). Anyhow the parts were all cleared / replaced.

 

I'm thinking that its either the rings, valve stem seals or the HG. It IS loosing coolant.. but there is no oil in it.. but there is blue smoke and erratic idling but only when hot. When its cold it idles nicely.

[Felly Magic]

If it was OMGHGF, the smoke would be white, this does point to kippered rings & valves

[RustyNuts]

Is there any way to determine which of the rings / valve stem seals it is?

 

If its the rings i'm obviously done for.. but the stem seals i'd be tempted to DIY. There must surely be a way to determine which is at fault?

[RustyNuts]

Well i found this on another motoring forum - anyone able to confirm if this is the case?
 
 

[Guest Hooli]

My experience of it is -

 

Rings smoke like a bastid & are worse on the throttle

 

Valve seals smoke like a bastid on the overrun

 

 

TBH if you're thinking of doing it yourself then rip the head off & have a look.

[STUNO]

The bit about not used since 2013 may be a bit of a clue. It may need a bit of time running to settle down. If it is not chuffing out white smoke (steam) or filling up the sump with water the water loss is probably external. As said blue smoke at all times and especially when foot to the floor is rings , after a nice long downhill with foot off the pedal and then foot down to go is most likely valve guides/seals. I had a Mazda 1300 that could put out a thick smokestream after a hill like that ! My current Mazda never smoked much, but when pulled apart the oil rings had completely collapsed.

[RustyNuts]

Hmm.. this is tricky either way as the car is sorn so can't even take it out for a test drive! As for taking the head off i'm trying to avoid that as the sheer cost of stretch boits alone will kill me financially yet alone a new gasket... and i don't even know if the head is straight as i've a funny feeling about the head gasket!

 

Bloody engines lol. Well i guess the only thing i can do is bodge the cooling system and then try and bodge it down the road to an MOT... at least that'll give me some sort of idea whats happening smoke wise lol.

[STUNO]

I think you have got the correct Autoshite way. Bodge, and if that is no good bodge some more 

[castros_bro]

Compression tester.

[RustyNuts]

I thought that too.. but apparently that won't diagnose duff oil piston rings or stem seals.. although good for the gasket which is dubious too. I'll dig it out later once pip squeek has gone to nursery..

[castros_bro]

Quote 

 

"""Cylinder compression tests are performed to identify any cylinders that may have poor compression. Inject oil into the weak cylinder after a normal cranking compression test has been performed. This is known as a wet compression test. It will indicate whether there's a bad valve, head gasket, or worn piston rings."""

 

 

 

http://www.freeasestudyguides.com/compression-test-injecting-oil.html

[twosmoke300]

Compression test won't show knackered oil control rings or stem seals though !

[sporty-shite]

Isn't there some sort of oil flush stuff that can free off sticky rings (FNARR FNARR). Can't remember the name of the stuff, but I remember using it in a particularly smoky 205 GTi, to good effect. 

[twosmoke300]

Snake oil I believe !

[RustyNuts]

Well thanks to my useless gunson compression testor that has the threaded part bent at a slight angle (how did they manage that) which is the second one from halfords to be like it, I had to test the cylinders twice.

 

Initially cyls 1,2,5 all came up low. 3&4 were at 220psi, 1 was at 190, 2 was 200 and 5 was 195. Because the tester doesn't screw in properly and puts more pressure on one part of the o-ring than the other side i ran the test again. This time tightening with all my might.. the three low cylinders all came up at 220 to match the other two.

 

So i (via a totally unreliable compression tester) have 5 cylinders with matching compression. And yes.. I know using an unreliable tester isn't ideal.. for some fucked up reason in my life all of my DIY / diagnostics / anything ends up relying on intermittent / useless crap lol. No idea how that works, it's just always ended up that way. My multimeter is intermittently reading current too.. somehow life expects me to work with that..

 

I've got onto gunsen about the tester.. its the second one with a fubar screw in part. The other one was a replacement for another that had a pressure valve decide to break half way through a test!!!

 

On a positive note the engine is still showing signs of mayo under the oil cap yet apparently i have normal compression on all 5 cylinders (according to my totally untrustable compression tester) so surely i can't have HGF?

[twosmoke300]

A head gasket can go between oil and water ways and not a/effect compressions at all . 

[twosmoke300]

5 cylinders ? is it a volvo turbo?

[castros_bro]

Could we have a hint as to what this engine/boat anchor* is?

Does it bung up fault codes?

Does the cooling system get over pressure is a very short time?

How long after starting and running on fast tick over does it miss behave?

Does it have per/post cat lambdas?

Does the crank case vent through the inlet filter? What is the state of the filter element?

Can you run it with the crank vent going to a "drip can" and not the inlet?

Do you have a friendly local with an exhaust gas analyser?

 

 

* delete as appropiate

[RustyNuts]

A head gasket can go between oil and water ways and not a/effect compressions at all . 

 

Theres no oil in the coolant though so i can't see that being the case. It's one reason i think the car is bloody haunted as its showing the symptoms of HG failure but not showing the signs other than mayo - which i'm told is probably condensation from the engine being sat outside for 2 years on a pallet.

 

5 cylinders ? is it a volvo turbo?

 

Close, renner safrane.. a pain in the arse safrane i may add. That reminds me i'm supposed to have started a dedicated thread with photos for it.. 

 

Could we have a hint as to what this engine/boat anchor* is? see reply to last comment and multiply the pain in the butt thing a couple of times

Does it bung up fault codes? No reader and i don't know anyone who has one that will fit this socket.

Does the cooling system get over pressure is a very short time? I have no idea to be honest with you. I have noticed the coolant is dropping but as the compression test is producing semi satisfactory results i can't see it being a leak into the cylinders or it would presumably blow the colling system apart?

How long after starting and running on fast tick over does it miss behave? 5-10 minutes.. then it starts to misfire slightly and gets progressively worse until it just refuses to run or restart.

Does it have per/post cat lambdas? Pre cat lambda.

Does the crank case vent through the inlet filter? What is the state of the filter element? Yes I think so. The breather on this is quite a complex murky beast but it does connect up to the air inlet pipework so I think thats what you mean.

Can you run it with the crank vent going to a "drip can" and not the inlet? No idea - normally on these lumps disconnecting any pipework seems to guarantee a stall.

Do you have a friendly local with an exhaust gas analyser? Possibly.. i'll have to ring round.

 

 

* delete as appropiate Done lol.. anchor is far more appropriate at this time lol.

 

Thanks for your continued help lads

[twosmoke300]

Is it a turbo ?

[RoadworkUK]

My header tank (turbocharged Audi) filled up with thick, viscous yellow/brown goop - I feared head gasket. Compression test was A-OK, so I looked elsewhere and found that the oil-cooler had gone south and was letting oil into the water.

[RoadworkUK]

Going by previous answers, I'm not sure that this is helpful.

 

Ben

OP mentioned signs of Mayonnaise. I'm pointing out another possible cause that could belay his HG fears.

 

Chris.

[RoadworkUK]

But the OP also "mentioned" that the mayo was not in the water or oil.

 

Ben

 

I'm not sure how your point helps.

 

Ben