Exhaust

[nicenic61]

Cupcakes,

Not posted for a while because surprisingly I've not had any problems. Actually, I have plenty of problems but they've just not got any worse.

I probably have the tattiest LS400 Mk4 lpg in the country, with a valid MOT. It's worth a bag of grapes (seedless, mind) and all the gravel you can eat but I love the old dear, although the lpg system cutting out going round roundabouts at 50mph and having to restart in transit is getting a bit tiresome. Would be nice to have a fifth gear as well.

The centre exhaust has started blowing, under the heat shields. This is the y-shaped bit. First place told me I needed y-bit and both cats replacing, over £1000. Ha, ha. Second place says the cats are fine, there's plenty of flange left, so only the y-shaped bit is needed, £493 inc VAT. It took them several hours to find the right stock. My local garage, who aren't exhaust specialists, says it's probably best to get it welded but was unsure of welding under the heat shields. First place says no chance of welding.

I'm off to try Kwik Fit now, just for a laugh.

If anybody has any thoughts or knows of a cheaper alternative I would be very interested....

Nic

[Malc]

Hi, just had my Mk3 exhaust bits around there welded to pass the MOT and to sort out the emissions ............ took my guy about an hour ...... a tricky but simple £35 fix :outforcount:

Not sure if it's the same issue with the Mk4 ...... don't know where you are .... . if you're near Margate in Kent I'll pass on his details to you.

By the way, the exhaust emissions changing to reflect how the car should be has resulted in the performance improving staggeringly ( the sensors now read properly I guess ) and you might find that with the emissions right and the sensor right reading then the engine just might not cut-out.

Malc

[messi]

Hi

I had the same issue, I went to quick fit for a Laff, got told £680 supply and fit y section, main dealers said £390, so obviously went to dealers

[The-Acre]

Had mine done recently, corroded pipe cut away, flange taken apart and refitted, a new section of stainless pipe, all for £100. I'm told it will be years before anything needs doing in that area again. Mine was leaking under the heat shield as well as the flange so it's repairable if you find a place that can be bothered or has the knowledge.

Phil

[Lexmanic]

got my whole Y section replaced by Top Gear Bridport for £200 AND its LongLife SSteel. They actually make it.

[nicenic61]

Cheered me up, perhaps welding is an option.

Kwik Fit quoted £623 but grunted about the cat flanges and getting the oxygen sensors out in one piece. Local garage knows a bloke called 'Jonno' who is a welder who I might get to see on Monday, failing that there is a bloke called 'Nobby' who also welds. Now if there's ever a welder's name it's either Jonno or Nobby so I think it's sorted.

Then there's just the MOT to pass. Might get that looked at first before I dive in with the exhaust weld, might be time for the old dear to visit the great Lexus Scrapyard in the Sky if there's any other bits wrong.

Nick

[Lexmanic]

Tried it myself, Welding never lasts

[The-Acre]

Tried it myself, Welding never lasts

Depends who does it and how much of the old is removed I would suggest. There's some excellent welders out there, and some mediocre ones, and some rubbish ones.

[Lexmanic]

Tried it myself, Welding never lasts

Depends who does it and how much of the old is removed I would suggest. There's some excellent welders out there, and some mediocre ones, and some rubbish ones.

Yup but unless your an expert welder how would you know The one I employed was supposed to be good but it started to blow again within days hence the replacement of the Y sections

[The-Acre]

Tried it myself, Welding never lasts

Depends who does it and how much of the old is removed I would suggest. There's some excellent welders out there, and some mediocre ones, and some rubbish ones.

Yup but unless your an expert welder how would you know The one I employed was supposed to be good but it started to blow again within days hence the replacement of the Y sections

The same thing happened on my MK2, welded, fine for a week, and then started blowing again, but they didn't remove any old sections. The garage where I took mine recently also make their own complete systems so I have more confidence in them knowing what they're doing. I did expect them to make a whole Y piece but they said it didn't need it in my case. Time will tell, and if I'm wrong I've got a great recipe for humble pie, I'll come down to Dorset and you can watch me eat it!

Phil

[crow1342]

got mine from inchcape lexus notts for just under 300 had it fitted for 60 at f1 in mansfield

[Malc]

My guy with the £35 welding fix assures me that it will probably last for many many years ... he's been looking after our cars now for 6 years and I have no reason to doubt what has to date been his sound judgement and work ethic.

Guess it depends on the skill of the engineer doing the work ...... as in many things in life !

Malc

[The-Acre]

My guy with the £35 welding fix assures me that it will probably last for many many years ... he's been looking after our cars now for 6 years and I have no reason to doubt what has to date been his sound judgement and work ethic.

Guess it depends on the skill of the engineer doing the work ...... as in many things in life !

Malc

I think you're absolutely right, skill and a good work ethic, the two don't always go together sadly.

[Lexmanic]

"good for years" Get it in writing

[bigegg]

As an amateur bodger all-round handyman, I have attempted to weld up blown exhausts on several occassions.

It doesn't work for long!

The problem is that exhausts corrode from the inside out. When they finally reach a point where they blow through, the rest of the pipe is very thin as well.

As soon as you weld the hole, you introduce impurities into the metal - soot from the inside of the pipe, gases from the air.

You also alter the alloy in what is called the "heat affected zone", as the lower melting point metals in the alloy are boiled away by the heat.

All this causes the area around the weld to be more suscebtible to corrosion, and means that it will fail again quite soon.

They *can* be welded perfectly if removed from the vehicle and scrupulously cleaned inside and out before welding *IF* the rest of the pipe isn't too badly corroded inside, otherwise it'll just blow through somewhere else any way.

Its usually as cheap, and easier, to simply fit a new exhaust than have it re-welded every three months.

[bigjap]

welding can be ok, if not too bad,but you have to have , good metal to weld to

[MNP]

If it's any help, the previous owner of my car had a stainless y piece made up by A44 Exhaust Centre in Worcester in May 2012, the cost all in according to the receipt was £228 fitted. Telephone 01905 424996.

Mark.

[nicenic61]

Just had it welded today by Geoff, a friend of Jonno. Geoff doesn't sound like a welder's name to me but it works, although he did say the exhaust was paper thin. Cost was 40, which I think is a bargain. Performance is much better now too. Earliest I can get my next MOT is late August so as long as it lasts a month....And I've got a boot load of heat shields for sale if anyone's interested.....Nick