cooking headers on a v6

[countrylife]

I had a complete car rebuild inside and out and a total rebuilt engine to original specs with all new parts including engine mounts, new hoses and all electrical items on my 2001 NM v6 3.5 petrol ,it was completely rebuilt from the ground up for a 5 year round oz trip constantly towing a 2000kg van, I also had a new set of headers and a custom straight thru exhaust fitted, runs lovely but, after 35,000km it has just destroyed another set of headers, it makes them leak where they come together from the manifold, i have replaced them again along with all the mufflers / cat and usual stuff and also changed oxy sensors after burning them in each time, I am wondering if it is running lean when towing under load and this is the problem, can anyone recommend an engine management company around Adelaide that is competent in these sort of things, Ive contacted a few companies with their standard emails in return and nothing that would inspire me to trust them to know how to fix it, any advice would be great

[dolphin]

wehat brand of header / extractors are you running ? i have had a set of Wildcats on my NM for over 4 years now without any issues atall. there is a reason for leaks at the joins and that is either excess vibrations and or cheap quality units. also i have allways had my extractors wrapped in a heat proof exhaust wrap from day one of fitment.

[Bundyk]

As dolphin said, cheap ones can let go as well. Seems the only ones that dont seem to fail are Wildcats (as dolphin has) or Pacemakers. (which mine will have soonish)

[countrylife]

sorry fellas but theres nothing cheap and nasty on my vehicle, mine are Genie wildcats, the problem has been looked at by them on 3 occasions and they have replaced under warranty each time by Genie Headers who make them, I have never had any problem before the new engine and towing constantly, I am considering fitting ceramic coated headers but I still believe it may be an engine mapping /tuning for the load problem that I will fix first

[Pauly Faulkner]

Does the exhaust have a flex pipe or spring flange at the cat? Without one of these, cracks will develope along welds in the headers.

[countrylife]

flex pipe fitted and replaced as well as new hangers and rubbers to eliminate any unusual flex caused by torque when towing, this is the third complete exhaust system thats been custom built by experts in custom exhausts, Ive really tried most things and spent heaps of cash on exhausts to try to solve this problem

[dolphin]

maybe your engine mounts have too much side flex. what i used to do with a super quick V8 Ford was to fit a torque bar or chain so the engine can not over flex with applied torque. sounds like this could be your main problem if all underboby exhaust rubbers plus a flex joint is fitted from header end pipe to cat section , V6 is the same as a V8 the way the engine rocks when you rev it hard . so enigine mounts and also check gearbox mounts.