NCT broken exhaust emissions

steve3194

Hi all, I had my car in for NCT this morning. It failed on emissions Lambda 1.18 on high idle shouldn't be above 1.03. And also on broken exhaust assembly stated as follows.

Exhaust system noise (54).....Exhaust Assembly.......Damaged/Broken

I rang mechanic and I have to bring the car to him next Monday so he can check which part of the exhaust it is. Won't get a price until he knows. He said the emissions are most likely related to the exhaust problem.

Car is a 99 corolla. Just wondering if anyone else had this before and what kind of price you paid/ would expect to pay

I was checking last years results and the lambda was 1.03 so it just about passed. Maybe the exhaust was startng to give trouble then.

I put dipetane in it this year and the CO and HC reading were down from last year. So that's one good thing at least. :-)

renofan

Do you not hear the exhaust blowing/being noisy along the underbody/front of the car? If the report states excess noise one or more parts of the exhaust system has probably rotted through.

steve3194

renofan wrote: »

Do you not hear the exhaust blowing/being noisy along the underbody/front of the car? If the report states excess noise one or more parts of the exhaust system has probably rotted through.

It sounds kind of loud near the back. The mechanic mentioned there was a hole the last time a I had a service. He said he didn't think it was anything to worry about obviously he was wrong on that. Hopefully it won't be too expensive

biko

As the mech said: without inspection it's hard to give a price.
Hopefully just a hole that can be welded.
If it's rattling too it may need a new brace somewhere to old it up.

steve3194

Do you lads think it will pass the emissions once the exhaust is sorted or do ye think it could be a separate issue?

biko

It's probably the hole only. Holes in the exhaust will mess with the lambda.
Earlier issues in the system will cause other issues.
All pure speculation at this point though.

In general it's not rocket science: Exhaust has a leak somewhere between the engine and tail pipe. NCT adds a device to suck air in the tail pipe => fresh air gets pulled in the exhaust pipe from the leaky bit. Lamdra reads high as there is extra oxygen in the exhaust.

steve3194

Thanks for your help. On a slightly unrelated note I have one other thing I was hoping to get some advice on. My car seems to be using a small bit if coolant roughly every two weeks. I topped up the radiator few weeks ago. Since then the level has dropped a bit. I'm not sure whether or not this is normal. The coolant is still visible when I open the cap just not as near to the top . I've attached a picture but it may be hard to fully make it out. I can't find any leaks Under the rad or overflow and I've also checked the waterpump and it looks fine. Oil doesn't appear cloudy either. I'm wondering of maybe it is supposed to be slightly low to allow for expansion?

I've also changed the radiator cap recently as the old one was rusted. I had noticed this before I changed cap however. Any help /thoughts would be great.