How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Matt Your Own Question

Matt
Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21117
Experience:  BEng hons Mech engineering, in auto industry 22 years
12772297
Type Your Car Question Here...
Matt is online now

my grande move failed the MoT . The exhaust emissions are too

Customer Question

my grande move failed the MoT . The exhaust emissions are too high. The engine does use more oil now. Are there any common problems with the exhaust emissions?
Submitted: 2 years ago.
Category: Car
Expert:  Matt replied 2 years ago.
Hello

If the cars has a high oil consumption and struggles to pass an emissions test its likely to be burning the oil and not leaking it out.

The first thing I'd check is the crankcase pressure relief valve (PCV) these are sprung loaded and are only meant to 'burp' excess pressure every now and then. The exiting gas is piped back to the inlet , however should the valve stick open then the engine tends to suck the air out of the crankcase all the time and this carrys oil over with it.

If you remove the air intake pipe and look inside where the crankcase breather is plumbed in you may find evidence of oil.

If you do find oil replace the valve. If this is all OK then its possible that the valve stem seals are past their best and are drip-feeding oil into the intake. These can be replaced without removing the head by a competent garage in half a day or so

an engine flush may also help if you've got a sticking oil scraper ring so its worth a go, as for the oil if you go up a grade / use slightly thicker oil then this is less readily drawn into gaps and less likely to be burnt off

Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21117
Experience: BEng hons Mech engineering, in auto industry 22 years
Matt and other Car Specialists are ready to help you
Customer: replied 2 years ago.

Thankyou for the information. Will changing the cat convertor help reduce the emissions enough to pass the MoT test.?

Expert:  Matt replied 2 years ago.
Hello Bill

quite possibly but before changing that out I'd try a bottle of this first as I've had good results with it

http://www.cataclean.com/

What Customers are Saying:

 
 
 
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil
< Previous | Next >
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C.
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex
 
 
 

Meet The Experts:

 
 
 
  • Greg

    Greg

    Technician

    Satisfied Customers:

    1067
    Automotive diagnostic tech
< Previous | Next >
  • http://ww2.justanswer.com/uploads/IN/indytech/2013-8-8_102717_SantoDomingo146598x6402.64x64.jpg Greg's Avatar

    Greg

    Technician

    Satisfied Customers:

    1067
    Automotive diagnostic tech
  • http://ww2.justanswer.com/uploads/35/350matt/2012-6-7_182356_matsavatr.64x64.jpg Matt's Avatar

    Matt

    Mechanical Engineer

    Satisfied Customers:

    4197
    BEng hons Mech engineering, in auto industry 22 years
  • http://ww2.justanswer.com/uploads/TE/techmachine/0601821347169_717372168_8940977_39623330_o.64x64.jpg Ross's Avatar

    Ross

    Diagnostic and repair technician

    Satisfied Customers:

    452
    Licensed diagnostic and repair technician
  • http://ww2.justanswer.com/uploads/RO/RobMechanic/068.64x64.JPG Rob's Avatar

    Rob

    ASE Certified Technician

    Satisfied Customers:

    82
    30 years trade experience
  • http://ww2.justanswer.com/uploads/UK/ukiaibal/2012-11-9_205920_SAM0109.64x64.JPG uk_iaibal's Avatar

    uk_iaibal

    UK Car Mechanic

    Satisfied Customers:

    1
    Verified Car Mechanic.
  • http://ww2.justanswer.com/uploads/NA/nabilc/nabilc_avatar.64x64.jpg Billy's Avatar

    Billy

    Trainer/ Master Technician

    Satisfied Customers:

    38
    Trainer 8+ years, master tech. 10+ years, SAE member
  • http://ww2.justanswer.com/uploads/MI/mikeamechanic/2013-4-2_175558_photo.64x64.JPG Mike Kelly's Avatar

    Mike Kelly

    Auto Service Technician

    Satisfied Customers:

    1256
    17 years experience as an auto mechanic, foreign and domestic. 5 years running my own repair business.