Failed MOT due to exhaust emissions + major oil leak

Technical Area Engine, Transmission, Exhaust etc
2

Hello folks,

Wasn’t sure where to put this but I’m after some serious advice, I’m not really sure where to start but I’ll try and cover everything that is troubling me with my 1.8l 1994 Eunos Roadster. Firstly I put it in for an early MOT today and it failed on exhaust emissions, below you can see a screenshot of that failure as well as the printout included on the exhaust emissions:

First question is, is this being tested correctly as from what I’ve read it should be tested as an import and have to meet different emissions than a UK car? Secondly, if it is correct then what would be the most likely cause of this in an NA? Cat, Lamba sensor, the aforementioned oil leak? (FYI. My exhaust is also blowing at the Cat but I doubt this would be the cause)
I’m just not wanting to get ripped off here and have to fork out a fortune for something that is an easy fix or even something that hasn’t been tested correctly.

 

Next is the oil leak, I was initially under the impression that this may be the rocker cover but looking myself it obviously isn’t, there is no oil around the rocker cover, there is oil everywhere else. All over the rear of the engine is oil and looking underneath, the whole underside of the engine is caked in oil. I didn’t realise it was this bad of an issue until actually looking at the amount of oil, according to MOT records, on and off the existence of an oil leak has been present since 2012 but due to it not appearing on all MOTs, I put this down to other minor leaks that have since been repaired.

See the images below for some crap shots of the amount of oil on the engine.

(right click image -> open image in new tab - for full size images)

Now after taking it to one garage, they said it looked like it was coming from a cam sensor, taking it to my main garage, they said the same thing a few weeks ago but when I handed them the keys over for MOT today and asked them to fix the leak, they’ve said after having a better look at it that it could be coming from the cylinder head but if that’s the case then worst case scenario, I’m probably looking at an engine rebuild. 

 

Lastly, on top of the dreaded ticking on start when the engine is cold, I also get a terrible grind at around 2000RPM, sounds like it’s coming from the transmission but it also happens when I push down the clutch, I’m guessing fitting a new clutch kit would be the first thing to do for that?

 

I realise the images are poor and the information is a bit vague but I’m kind of panicking at how much this is all going to cost and any help would be much appreciated.

I only took the bloody thing in for MOT early to see if any of the rust would cause it to fail so I could get that sorted but it’s come back with a myriad of other problems instead and no mentions of the rusty bits.

Any recommended garages for MX-5/Eunos MOT/servicing/repairs would also be welcomed, I’m in the West Midlands but am happy to travel a reasonable distance.

 

Thank you in advance, if any more information is required to more successfully answer these questions then please let me know.

John

3

Looks like it’s time for a new Car!

4

Oil leaks are really difficult to diagnose.

Most on the MX5 are CAS ‘O’ ring or rocker gasket so I would recommend renewing those. I had a persistent leak on our Eunos and eventually cleared it by fitting a genuine Mazda rocker gasket where several aftermarket ones had not worked for me.

Has it failed the MOT on this? - there may be an advisory but it should not fail on a small oil leak.

If you have a leaking cat, emissions and lambda will be all over the place. In your position I would replace the cat and give the car a good service - oil, filter, air filter, plugs. leads, etc. It passed on hydro carbons but that reading is very high for a healthy car - mine was about 9 ppm at the last MOT IIRC. With the air leak and possible service items requirement, you have not really given your car a fair crack of the whip on emissions. 

Car has high mileage but if it still has good compression and does about 30mpg, can’t be a lot wrong.   

5

I had an oil leak at the back of my engine it was the cas oil seal and rocker gasket, I was having the clutch changed at Sam Goodwins in Nuneaton  they have been working on MX5’s since they were first made so asked Steve to check for my oil leak as it was dripping out the clutch bell housing and smelt of steam engines, he said the bell housing was full of oily crud as it was working it’s way from the back of the engine.

All fixed in a day and no more leaks.

6

I shall try and get both of those replaced (time to book a week off work to properly get the thing sorted, I reckon.)

No the oil leak was not a failure, just an advisory.

 

I took the car to London and back around a month ago (300 mile round trip) and it averaged 33mpg. Nothing wrong with the fuel consumption, as soon as the engine is warmed up the car usually feels just fine to drive.

Is a replacement cat expensive? I’ve heard figures as high as £900 thrown around but it isn’t something I’ve really looked into.

 

Additionally, the amount of oil the engine is using (ignoring the leak itself) seems just fine (according to the dash anyway) and the engine temperature is fine, although the transmission tunnel does get very hot on a long run.

 

Thanks for the help so far.

7

I’ve heard a lot about Sam Goodwins, I’ll look into it and give them a go, thanks for the suggestion.

 

8

You’ve had the correct test for your car (basic emissions test) Not sure how up to date this is but have a look here

http://mazdamenders.net/forum/viewtopic.php?f=17&t=3236&start=0

You could fit a decat pipe which is significantly cheaper than a replacement catalytic converter and still be OK? As others have said, the oil leak (more than likely) is cam cover gasket/CAS O ring, neither being expensive or hard to do. Rhino666 is spot on regarding service items? Always worth doing and again not expensive? A really good blast before the test, with engine good and hot, won’t forget any harm either?

Barrie

9

My previous MOT tester (of many years experience but recently retired) advised me that they had been warned by VOSA not to allow any car that had a cat convertor removed to pass the MOT test, at risk of losing their licence. In any case, doing so would make CO emissions worse - the cat is only there to convert CO to CO2.

In view of the oil leaks, as well as emissions problem, I’d also want to thoroughly clean out the engine venting system (whatever it is on the NA, I have never owned one).

10

Went into the garage today and they reckon either the lambda sensor or oxygen sensor is at fault for the emissions and they’d see about replacing those and getting it through MOT next Thursday., I might try a fuel additive though just to make sure I can get the lowest reading possible and be good for another twelve months.

11

What was the outcome please? I’m having a similar problem with emissions 

12

Emissions could be the o2 but in our case on our 1990 it was the AMF, we opened it and adjusted the spring and all was well.   As the OP mentioned there is a different test for older cars so its important to point out the manufacturing date not the import date when having it tested.

13

You could try the diagnostics socket. There are guides on this forum and internet in general on how to read and decipher the fault codes. That was how I tied my failing emissions down to the O2 sensor

 

14

Bit late to jump in here but the eunos shouldn’t have failed as theres no emissions data for imported vehicles which the eunos is so it should have been a 3.5% limit 

when the car failed the first test it should have been then tested with a full cat test this requires make model engine size etc , these details are not available in the emissions data for an eunos only an mx5 .

15

So, here’s what happened.

After this whole MOT thing, the car still had MOT left on it, so we went for a drive to Windsor (we’re from the West Midlands btw) during this trip I managed to ruin the engine, the valve stem seals had gone and so for the past month my Eunos has been having an engine swap. When I got it back, it passed emissions fine, so I’m guessing it was the fact that almost every seal was leaking and the engine was on it’s last legs.

Not very helpful for others but that’s how the situation panned out.

16

Personally I’d try Redex with premium fuels (Shell V-Power) to try and give things a clean. That and a good service is all I can really recommend, not being a mechanic and all

 

17

It’s being scanned on Sunday to check for faults, but a service and Redex sounds like a good shout