MOT fail due to CO non lexus

jackcramerr · April 2, 2017

The car is consuming oil. Lots of it but no smoke. Last year did a compression test and results were ok but I am going to perform it again.

In case it is a pass, is it safe to say it will be valve seals? How can I confirm it?

And for valve seals, I saw vidoes that does not require head to be removed. Having no experience, do I have to remove the cams completely? I think answer is yes, generally speaking, what will that entail?

What bolts will need to be undone and what will I need to replace? Will I need to remove the timing chain as well?

madasahatter · April 2, 2017

1 hour ago, jackcramerr said:

The car is consuming oil. Lots of it but no smoke. Last year did a compression test and results were ok but I am going to perform it again.

In case it is a pass, is it safe to say it will be valve seals? How can I confirm it?

And for valve seals, I saw vidoes that does not require head to be removed. Having no experience, do I have to remove the cams completely? I think answer is yes, generally speaking, what will that entail?

What bolts will need to be undone and what will I need to replace? Will I need to remove the timing chain as well?

What make of car? Best thing to do have a look on utube at some body doing what you propose to do. Failing that google is your friend.

jackcramerr · April 3, 2017

Mazda 3. They tend to take ford engine. Very unreliable car.

johnatg · April 3, 2017

Why not ask the question on a Mazda3 forum?

I look after one (which is perfectly reliable) - but the answer to your question depends on the year and exact engine - most have Zetec-derived engines but there are several different capacities etc and recent ones don't have Ford engines.

madasahatter · April 3, 2017

3 hours ago, jackcramerr said:

Mazda 3. They tend to take ford engine. Very unreliable car.

My mates Maxda 6 takata drinks 2 litres a week no tell tale blue smoke. No obvious leaks had it on a pit can not find anything, card under car no drips.

My last car drank a litre every 1000 miles Skoda Vrs its within the bounds even mentions it in the hand book.

jackcramerr · April 3, 2017

It's a 2006 2.0 petrol.

There used to be mazda 3 forums uk version but I did not find people friendly or knowledgable.

I might try mazda US forums.

I am not very convinced that consuming oil is a normal thing. No smoke can be due to Cat converter blocking it, right?

The car failed CO emissions once and barely passed the second time. If oil consumption is not related to it then I can sleep over it but if it is, it will go worse.

As for valve guide seal, I think I have to remove side cover and remove the chain. Big job. So first need to learn how the timing adjustment is done. Also brings the question if it is indeed the seals or something else.

madasahatter · April 3, 2017

http://www.mazda3forums.com/61-powertrain-2004-2009-mazda3/377727-excessive-oil-usage.html

This i what i told my friend the Pcv valve not breathing properly. On certain vehicles revs rise while in stationary traffic 2000 to 2500 revs then drop

back down again.

jackcramerr · April 3, 2017

I replaced the PCV last year because of oil consumption. The original one was perfectly fine as well.

It did not make any difference.

The reason I also changed PCV was if engine is running, and I remove the cap for oil fill hole, air blows out of it. So I thought it might PCV. It did not help.

If you check is250, when car is started and remove the oil fill cap, you will notice suction instead of air blowing out.

johnatg · April 3, 2017

Maybe it's a LF model.

The tappets are buckets which sit on top of the valves, then the camshafts are directly on top of the tappet. There are shims which sit in the bucket to adjust the valve clearance - if they need adjustment you have to measure the existing clearance and the shim, then buy new shims of the new size you've worked out. It is sometimes possible, with an arrangement like this, to winkle the shim out whist you hold the valve compressed with a special tool which presses on the edge of the bucket. The official way is to remove the camshafts - you don't need to remove the timing chain but you do need special tools to lock it all up whilst you remove the camshafts.

And I reckon changing the valve stem oil seals is going to involve removing the head. As you say, pretty major job.

If the oil isn't leaking it must be being burnt. Most likely past the piston rings if it's done a high mileage. Either live with it or budget for a pretty major overhaul.

Or there is some stuff advertised in Car Mechanics every month which claims to restore engine compression and improve oil consumption, especially for the Mazda RX8 which has a ****el (edit - oh - ridiculous - that's a rotary) engine and it is notorious for high oil consumption (in fact it's designed to burn oil to save the rotor tips). I can't remember the name and I don't have a copy of the mag to hand, but it might be worth a try (but it could well be snake oil). I'll try and remember to send you the name when I get home towards the end of next week.

johnatg · April 3, 2017

2 hours ago, jackcramerr said:

The reason I also changed PCV was if engine is running, and I remove the cap for oil fill hole, air blows out of it.

Excessive crankcase pressure - worn engine/piston rings - probably.

Shahpor · April 3, 2017

You can't say ****el on here?

Edit: Guess not

jackcramerr · April 3, 2017

Thanks John.

I do not feel loss in power.

I will re-do compression test. Maybe the values changed now but last year it were to spec.

It sometimes takes longer to start the car but that's the only thing I have noticed.

You can do seals without head removal. To hold the valve up, either fill the chamber with air or use rope. So you feed the rope in as much as you can, then bring the piston up to force hold the rope aginst the valve. Seen a few vidoes of it now.

jackcramerr · April 3, 2017

The biggest problem at the moment is not topping up but is possible mot fail.

I always wonder how the cars on the road that produce cloud of smoke pass mot...

doro708 · April 4, 2017

On 2/28/2017 at 1:22 AM, madasahatter said:

Cataclean works briliantly.

I had the same experience with the Cataclean on a Vauxhall Astra 1.6 and it passed me the MOT on emission after the first bottle .

madasahatter · April 4, 2017

On 07/03/2017 at 4:00 PM, johnatg said:

Maybe wait until next time - but do it a month or so before the test at least and put the Cataclean in a half full tank and run it near to empty. Try and do some spirited driving on the way. And use the car more regularly - or sell it!

Redex and similar fuel cleaners are more for cleaning the fuel system and injectors (which certainly can help emissions) - Cataclean is more specifically for cleaning the oxygen sensor and cat. But it can't restore totally shot stuff.

I have used this before and does work to a degree.

http://www.ebay.co.uk/itm/Quality-Car-Oil-Top-Up-Addative-Built-In-Engine-Stop-Leak-Gasket-Seals-Sealer-/360911133273?hash=item5407fada59:g:5qIAAOSwB-1YorKh

rayaans · April 5, 2017

On 4/3/2017 at 0:06 PM, madasahatter said:

My mates Maxda 6 takata drinks 2 litres a week no tell tale blue smoke. No obvious leaks had it on a pit can not find anything, card under car no drips.

My last car drank a litre every 1000 miles Skoda Vrs its within the bounds even mentions it in the hand book.

High oil consumption is normal on some cars - the only reason its not "normal" is because some owners cant be bothered topping it up and make the engine blow

Few examples are the VAG group 1.4l supercharged and turbocharged engine in the fabia vrs, polo gti and Ibiza Cupra. I believe some rotary engines love oil as well.