Possible MOT failure?

[Pinch]

Hi Chaps,

I've recently discovered my old Jag is blowing very slightly from one of the exhaust manifolds and to replace the back one is apparently an engine out jobby. :shock:

First up, I need to locate the leak and hope it's the front manifold. It could be one of the manifolds has worked slightly loose from the engine block :eusa-pray: , or one of them has cracked, which is apparently quite common with these old Jags.

My two questions are: (1) Is this an MOT failure? (2) Can a cracked manifold still be welded these days?

I spent much of last night Googling for answers, but I haven't got very far. I can always phone the garage in the week and ask them, but before that, I thought I'd post the questions on here.

She failed the MOT last year on emissions, which cost £500 to have the two oxygen sensors replaced, so she should fly through this year's emissions test. But strangely, since the sensors were replaced last year, I've experienced two minor issues; (1) a slight change in the sound of the exhaust (although the off-side tail pipe was also replaced for the last year's MOT) and (2) there is a slight and occasional misfire. Although at the time, I popped in to see the mechanic who carried out the repairs for the MOT about these issues and his response wasn't very helpful. Trouble is, I rarely use the Jag and the time has flown by - almost a year.

I have tinkered around during the last year, including the replacement of one of the coil packs, a new set of spark plugs and I also replaced the rocker cover gasket while the cover was off. The misfire is still there although very slight and not continuous.

If any of you chaps have knowledge on the above issues, I will be very grateful.

Cheers,

 

[9fingers]

My tame mot tester used to let one of my cars through with a minor leak at a joint which knew was very difficult to keep sealed due to movement. You need a pragmatic tester used to coaxing older vehicle through. The misfire is more concerning as this will affect the hydrocarbon emission figure due to unburnt fuel in the exhaust.
Yes cast iron can be welded but it is a specialist job and might need machining after to remove distortion. You might be able to bodge it with a metal loaded epoxy enough for mot and immediate sale as you clearly don't need the vehicle. I got rid of my much loved 22 year old pug this year. Just not sensible to keep for 200 miles per year.
Good luck
Bob

 

[Malc2098]

Paul,

From my Vehicle Examiner days, we were taught that technically, any escape of exhaust before the tail pipe is a Construction & Use offence and therefore an MOT failure.

In addition, this leak could probably be the cause of the misfire, due to the possibility of reduced back pressure because of the leak.

Not the answer you're possibly hoping for, but any other members with greater experience can shoot me down.

ATB.

 

[Pinch]

My tame mot tester used to let one of my cars through with a minor leak at a joint which knew was very difficult to keep sealed due to movement. You need a pragmatic tester used to coaxing older vehicle through. The misfire is more concerning as this will affect the hydrocarbon emission figure due to unburnt fuel in the exhaust.
Yes cast iron can be welded but it is a specialist job and might need machining after to remove distortion. You might be able to bodge it with a metal loaded epoxy enough for mot and immediate sale as you clearly don't need the vehicle. I got rid of my much loved 22 year old pug this year. Just not sensible to keep for 200 miles per year.
Good luck
Bob

Thanks Bob. I'm not sure if the garage we use for our MOT's is a pragmatic tester for older vehicles - maybe they are. But, when the garage failed the Jag last year on emissions and off-side tail pipe, my mechanic chap carried out the repairs and he would have gone back to the garage for a retest on the emissions (I would have thought), so the garage must have noticed there was a slight leak from one of the manifolds. Before the MOT, there was definitely no leaky manifold, but after Shaun (mechanic chap) replaced the sensors, I noticed the Jag sounded different and it's not been quite right since. I know one of the tail pipes was replaced too, but this difference in sound was coming from the engine bay. I know Shaun had a problem removing one of the sensors and he had to re-tap the thread. It sounds like I'm pointing fingers I know, but it is a bit strange or coincidental. The slight misfire was also a new development since the last MOT repairs and I wonder if it's anything to do with the leaky manifold. I've let this drag on a bit and it's almost a year later. :|

I would like to sort out the manifold properly and I'm up for doing it myself, but if it is the rear manifold and the engine needs to come out in order to replace it, I'm in a bit of limbo. I've just been tinkering around with the Jag today and I'm thinking I might SORN it for a few months and investigate this leaky manifold. I can't see anything at the moment until I remove the manifold heat shield, which is also a swine to remove.

Sell the Jag sir! :shock: You cannot be serious! :lol:

Nah, I won't sell the Jag... I probably drive around 2-3k a year in her with a classic insurance threshold of 3999 miles a year. I've had a few of these over the years and although I don't use the Jag much, when we do go out on a trip, she is such a pleasure to drive and so comfortable.

I've had a few Pugs - lovely motors. My last one was a 406 coupe 2.1 turbo conversion and it went like stink, but that was 10 years ago and I've grown up a little bit since. :|

 

[Pinch]

Paul,

From my Vehicle Examiner days, we were taught that technically, any escape of exhaust before the tail pipe is a Construction & Use offence and therefore an MOT failure.

In addition, this leak could probably be the cause of the misfire, due to the possibility of reduced back pressure because of the leak.

Not the answer you're possibly hoping for, but any other members with greater experience can shoot me down.

ATB.

Thanks Malc. Yep, that would make sense to me, and probably the only way to go really. I do get the odd sniff of fumes in the cabin of the Jag which is obviously coming from the leaky manifold. Ah yes, I wondered that about the misfire and just mentioned this in my above reply to Bob. As mentioned above; before last year's MOT, the Jag was silky smooth and didn't miss a beat, but since the sensors were replaced, she has a leaky manifold and a very slight misfire. The misfire is a strange one... she pulls fine and drives well with the occasional slight miss. The weird one is when you're cruising at say 50 MPH, all is fine and then she suddenly loses power and I have take my foot of the pedal, re apply it and she's away again. It's nothing to do with the pedal by the way. On tick over, you can hear and feel a slight intermittent miss as well.

Again, as mentioned to Bob, I've been tinkering around today with the Jag.. well, I cleaned Mrs P's Mini first (brownie points) (she's off up north tomorrow and then flying to Amsterdam with her daughter to see friends - home alone for the week :eusa-dance: ), and then onto the Jag. She has a flat battery at the moment (first time ever) and she won't jump start from the Betty the Beemer (annoying - I'll have to borrow a booster from a pal) (plus, I can't get the bus into a good position for the leads to reach - day-um!), and, the near side front tyre has a slow puncture, so I've put the space saver jobby on for now until I get the punctured repaired during the week. I'm rambling...

As everything is up for renewal next month, I might SORN the Jag for a few months to give me time to investigate and hopefully sort these issues out.

 

[9fingers]

Paul, I'd somehow formed the view that you were only doing trivial mileage in the Jag and so if it was turning into a money pit, selling would be the right thing to do but a few thousand miles pa does mean you are getting reasonable use out of it.

Good luck with the fixes

Bob

 

[RogerS]

..... It sounds like I'm pointing fingers I know, but it is a bit strange or coincidental. .... :|

You're thinking what I'm thinking. Especially your comment re his attitude...how well do you know him? Is he always like that?

 

[RogerS]

Paul, I'd somehow formed the view that you were only doing trivial mileage in the Jag and so if it was turning into a money pit, selling would be the right thing to do but a few thousand miles pa does mean you are getting reasonable use out of it.

Good luck with the fixes

Bob

So, so tricky with old cars. I've shovelled money into the Discovery recently but it is a convenient workhorse (when not in the garage being fixed again). I've shelled out an awful lot over the last couple of years and the decision is always whether to cut and run or poor in more money.

Fortunately, I know that next year it will fail the MOT due to needing a new sub-frame. I shall sell it when the house is finished.

 

[Malc2098]

Might be off base, but could a manifold leak cause an SU carb's vacuum lift of the piston to be messed up, hence misfire?

 

[9fingers]

Dunno Malc. With Paul referring needing sensors being replaced in the context of emissions, I'd assume this vehicle would have a fuel injection system rather than carburettors.

Bob

 

[Malc2098]

Dunno Malc. With Paul referring needing sensors being replaced in the context of emissions, I'd assume this vehicle would have a fuel injection system rather than carburettors.

Bob

Yes, Bob, I assumed 'cos Paul said 'old' that it would be normally aspirated! In any case, a manifold leak, whether inlet or exhaust, is going to make for some dodgy running, and if exhaust, possibly MOT failure.

I'm concerned that Paul has said he gets the odd sniff of fumes. Paul, that's really dangerous. In a closed saloon, that CO! Carbon Monoxide!

 

[9fingers]

I'm concerned that Paul has said he gets the odd sniff of fumes. Paul, that's really dangerous. In a closed saloon, that CO! Carbon Monoxide!

Agreed Malc, more info is gradually coming out indicating that it needs fixing properly.

Bob

 

[Tusses]

AFAIK any exhaust leak is a fail .. and dangerous .. hence the fail.

As bob said, metal epoxy might bodge it , even permamently

I'm with Malc on the confusion when you say "old" .. and then "sensors" ! lol ...

as for the misfire .. need to know more about how "old" it is !
Sensors can be a pain to troubleshoot.

Carbs can be systematically cleaned. and air tubes/ vacuum tubes checked for leaks etc.
WD40 is good for that. If it's missing, and you spray a tube/hose and the engine note alters, then that indicates and air leak / deteriorated hose

 

[old]

Are you sure its engine out with a straight 6 engine within a large car two manifolds rearmost leaking seems unlikely to me if the above applies.

 

[Malc2098]

Just to assist with the legal position : -
The Road Vehicles (Construction and Use) Regulations 1986
CONTROL OF EMISSIONS

Silencers
54.—(1) Every vehicle propelled by an internal combustion engine shall be fitted with an exhaust system including a silencer and the exhaust gases from the engine shall not escape into the atmosphere without first passing through the silencer.
(2) Every exhaust system and silencer shall be maintained in good and efficient working order and shall not be altered so as to increase the noise made by the escape of exhaust gases.
(3) Instead of complying with paragraph (1) a vehicle may comply with Community Directive 77/212, 81/334, 84/372 or 84/424 or, in the case of a motor cycle other than a moped, 78/1015.
(4) In this regulation “moped” has the meaning given to it in paragraph (5) of Schedule 9.

So the, debatable issue for a pragmatist is , are the gases escaping before passing through the silencer. So if the tail pipe is dodgy, that may not be an MOT failure if the gasses have already passed through the silencer. Any escape upstream of the silencer has therefore got to be an offence.

 

[Woodster]

When I trained as a mechanic I was taught that any leak of exhaust gasses before the tailpipe was dangerous. A blowing exhaust manifold would have been an immediate MOT failure where I worked years ago.
There was a young lad recently that killed himself and his girlfriend by carrying out modifications that allowed exhaust gases into his car. If you can smell exhaust gases you shouldn't drive it until you can get it fixed. Even if you don't care about yourself you could end up killing someone else if you pass out behind the wheel.

http://www.bbc.co.uk/news/uk-england-essex-39339063

 

[Pinch]

Paul, I'd somehow formed the view that you were only doing trivial mileage in the Jag and so if it was turning into a money pit, selling would be the right thing to do but a few thousand miles pa does mean you are getting reasonable use out of it.

Good luck with the fixes

Bob

Cheers Bob. Yep, I agree. I've double checked and in two years of owning the Jag, I've put just over 4k on the clock and most of that was in the first year. Since the last MOT, I've done around 500-700 miles. I would have driven more, but the issues have put a damper on things.

 

[Pinch]

..... It sounds like I'm pointing fingers I know, but it is a bit strange or coincidental. .... :|

You're thinking what I'm thinking. Especially your comment re his attitude...how well do you know him? Is he always like that?

Cheers Roger. It's a tricky one... Shaun's garage is on the same farm as my workshop, although on the other side of the estate. I only started going to him a couple of years ago when one of my work neighbours recommended him, so too did the farmer (the landlord), who takes all of his vehicles to Shaun. So, a couple of years ago, he trial tested my work's van (the bus) before the MOT. He stopped a weeping brake pipe leading to the n/s rear drum brake, and welded a broken down joint in the exhaust - it did sound better afterwards, although I wasn't aware it was blowing - it sounded okay. Anyway, I collected the van (only a 10 minute walk from my shop) that night ready for the following day's MOT.

As I drove the van to the MOT centre the next day (about 5 miles away), I could smell a burning of friction, but wasn't sure if it was coming from outside. I arrived at the MOT garage (same garage who have MOT'd my van for the last 4 years), handed over the keys and sat in the waiting room. The MOT tester came in after the test saying everything is fine, BUT, the rear n/s brake is almost jammed. I quickly put 2&2 together and told him the story. The MOT chap told me to get the van back to Shaun to rectify his carelessness and return the van back to the MOT garage before 5pm for them to issue a pass.

I phoned Shaun on route and gave him a bollocking!.. Telling him to be ready as I was going to be at his garage in 5 minutes. When I arrived, he was ready with nothing on the ramp, so I drove up onto the ramp and he sorted the problem while I watched him. He said, "I thought you were going to drive the van home last night, which would have freed the brake before the MOT." :shock: I felt like giving him both barrels. Instead, I gave him a glance and drove off.

That was that... I went back to him 6 months later for a minor repair on the van and that was okay.

I then took the Jag to him for last year's MOT check up.

Although I haven't been to him since, it was convenient as it's an easy drop off and walk back to the workshop. His attitude isn't good at all, which I found amusing and maybe, this rattled him - I really don't know. Other folk still highly recommend him. If he is responsible for the leaky manifold on the Jag, he's cost me a few quid. :|

 

[TrimTheKing]

Sounds to me like you've had 100% poor experiences...

Mark

 

[Pinch]

Sorry chaps, the Jag is 23 this year (1994). I know that's not vintage, but still old.

The fuel system is injected - 3.2 straight six.

Malc, yes, cheers matey, I know it's dangerous, which is partly why I don't drive her that much at the moment. The fumes are occasional, it isn't constant by any means, and my window is always open, even during the winter months. But, yep, any exhaust fumes entering the cabin isn't good. Thanks for the legality info by the way, very interesting notes.

 

[Pinch]

Sounds to me like you've had 100% poor experiences to me...

Mark

Yep, certainly with Shaun... I'll go and park a darky in his garage when he's not watching! :lol:

 

[TrimTheKing]

Sounds to me like you've had 100% poor experiences to me...

Mark

Yep, certainly with Shaun... I'll go and park a darky in his garage when he's not watching! :lol:

:shock: :lol:

Where's that poop emoji??!! :lol:

 

[Pinch]

AFAIK any exhaust leak is a fail .. and dangerous .. hence the fail.

As bob said, metal epoxy might bodge it , even permamently

I'm with Malc on the confusion when you say "old" .. and then "sensors" ! lol ...

as for the misfire .. need to know more about how "old" it is !
Sensors can be a pain to troubleshoot.

Carbs can be systematically cleaned. and air tubes/ vacuum tubes checked for leaks etc.
WD40 is good for that. If it's missing, and you spray a tube/hose and the engine note alters, then that indicates and air leak / deteriorated hose

Thanks Rich, all mentioned above matey - 23 years old and fuel injected. I've actually wondered whether the mechanic has installed them the wrong way round.

 

[Pinch]

Are you sure its engine out with a straight 6 engine within a large car two manifolds rearmost leaking seems unlikely to me if the above applies.

Cheers Chris, this is purely by what I've researched on the internet - I don't know. I'm going to SORN the Jag and when time allows, I'll remove the heat shield and investigate further. I must admit, removing the engine to remove the rear manifold seems like a very unfair task.

 

[Pinch]

When I trained as a mechanic I was taught that any leak of exhaust gasses before the tailpipe was dangerous. A blowing exhaust manifold would have been an immediate MOT failure where I worked years ago.
There was a young lad recently that killed himself and his girlfriend by carrying out modifications that allowed exhaust gases into his car. If you can smell exhaust gases you shouldn't drive it until you can get it fixed. Even if you don't care about yourself you could end up killing someone else if you pass out behind the wheel.

http://www.bbc.co.uk/news/uk-england-essex-39339063

Cheers Woodster, that's sad - silly boy!

Indeed, it's a good job I do care about myself and other people around me.

 

[Pinch]

Just thought I'd share...

My little Beemer has recently passed the MOT and while I was there, I asked the chap about the Jag's slight blow from one of the manifolds. He said if the blow is slight and it doesn't affect the emissions test, it will be okay.

 

[9fingers]

I could see how an inlet manifold leak would screw up emissions but a minute leak for an exhaust manifold should have minimal effect on exhaust back pressure and should not get picked up.

Sound like a sensible, pragmatic guy. If the computer says "no" on the test he just cannot ignore it as the printout has to be filed. But if it is just a little noise then not a problem.
My chap always let a slight blow under the floor through as he knew that even if sealed up the joint would flex on the next pothole and blow again. You eally had to know the sound of the car to detect the leak and the sooty tell tale mark was tiny over a years motoring.

Fingers crossed for you

Bob

 

[Pinch]

Cheers Bob.

Yep, I'll unsorn the Jag in a few weeks and give her a try.

:text-bravo: