Evilmunkey

or Blackmail a Politician. .

CarolinaGirl

"Senator, I know you've been pole-dancing to pay for an exhause manifold"

CarolinaGirl

Answer, Part A from a professor of Mechanical Engineering and Ph.D.,P.E.,CSP,CPE,CQE,CRE
at Lawrence Technological University in the Detroit area:

you ask what appears to be a simple question but which in reality can become very involved.
It depends on the nature of the crack, the crack causation, and the development of any further stresses to cause the crack to grow.
Generally, if a crack exists and is visible by the naked eye then that crack will probably continue to grow.
If the crack is small and stable (i.e. not visible growing) then I would tend to agree that there is little or no potential for danger to other parts of the car, but as was noted to you there would be increased danger for enhaling exhaut fumes in the passenger compartment.

So yeah, that doesn't tell us too much; I've asked follow up q's re: what if the crack is big, worse case scenario, re: valves, pistons etc, per some of the specific comments from her...e not the ones about pole-dancing however : )

cackalak han

The replacement part from O'Reilly's is $160 with a lifetime warranty. If you can't afford that, you can't afford to drive, period.

JeEVeS

I know not of the damage but i know i replaced mine with a pacesetter header. Not a bad idea but not a great one. at least it wasn't cracked however it was loud (thin metal). I have since upgraded to an LCE. Where are you located? I still have the pacesetter for what in my opinion would be a little more long term than a JB weld fix but not much.

CarolinaGirl

<<The replacement part from O'Reilly's is $160 with a lifetime warranty. If you can't afford that, you can't afford to drive, period. >>

For most concientous consumers, much more goes into prioritizing repairs than the mere cost of a part.

First, the PART is only have the cost of such a repair, at least around here.

Secondly, one has to decide if such a repair is worth it on a car with $225k and several other problems. (In my case, I've already driven it at least 5-10k miles without any loss of power, fuel economy, poisoning or signs of further problems. And that's 25k past when folks recommended reading it's last rites.)

Third, $250 is 50% of annual operation cost ($500/yr in gas, taxes, inspection, registration).

Third, if someone's income is very tight, as it is in this economy, $250 could be 2-3 months groceries.

But more importantly, even if your budget is not that tight, if the crack is not doing any real harm, it's just plain foolishto throw away $250, or even $160. Even if a millionaire, I could not in good conscience throw money away. But hey, if you have money to waste, more power to you.

Which is why I'm looking for sound scientific
data (rather than anecdotal) to factor into economic conditions, including age and condition of vehicle, to conduct cost-benefit analysis upon which to make an informed consumer decision.

Note the engineer Ph.D.,P.E.,CSP,CPE,CQE,CRE
did not say that it always did damage --ie doesn't always damage exhaust valves, pistons etc as many assume--but instead stated that it depended on a range of conditions. That makes assessment more difficult, but still doesn't mean the repair is necessary.

DeathCougar

iTrader: (23)

So I am confused then. What is the point of your postings, if you never intended to fix the vehicle? To dissuade others from fixing their vehicles? It really is this simple: If its broken, fix the problem. If you don't want to, fine drive it until the car won't drive anymore (related to the manifold or not is irrellevant)

I like having all the systems on my vehicle operating properly, without the risk of damaging the engine. I also don't want to hear the constant TICK TICK TICK of the exhaust.

What is the other half? Labor? Lets assume for arguments sake that everyone in this thread is capable of fixing their own vehicles. That is, after all, the point of yotaTECH.

Lumpy

Hear hear!!!

omg I'd fix the thing and be done with it, will be better in the long run. even stock manifolds are not all that much.

Carolina when it craps out on you fix it then and replace what ever else it took out with it.

CarolinaGirl

I stated, in my first posting, that I, like others, have received conflicting information about this issue and, like others, was seeking sound information upon which to make an informed decision about whether it was worth it to fix it.

When all I saw on this board was MORE conflicting information, I decided to go to those who actually design and scientifically study these things. Others stated that they would also be interested in such information. I posted the first response last night, waiting on other university researchers to respond.

Thus far, the scientific information I've procured does NOT back up claims posted here that not fixing the crack will cause further damage. Sorry if that ruffles your feathers.

However, I'm still waiting on further information from other reputable sources before making final decision.

The fact that I have a vehicle with 225,000 miles, that is still running smoothly and getting 30-34 mpg, at minimal M&R expense, must mean I've been doing something right in regards to making decisions about this vehicle and will continue to do so.

I'm not telling YOU how to make your decisions, so I'd appreciate if you would please refrain from chastising me or questioning my motives if I choose to use scientific rather than anecdotal information, and come to a different conclucion than you.

Lumpy

Scientific or not what happens in the field is going to be different from lab results. What were saying is that if its "broke fix it". You may have a smaller leak than the OP in this but either way it is not helping. This may not be causing too much harm now but in the end it will "probably" cost you more then than it will now.

CarolinaGirl

Not everyone who tunes in here fixed their own vehicles, but every mechanic I've ever dealt with appreciates an informed customer.

However, I used to fix my cars myself, and was once offered a job in shop as a mechanic. As far as my car, I know enough about it to know it's much more likely to 'crap out' from something other than this. Yet I still like to learn new things and be an informed consumer.

A better question is why are some of the people here so threatened by someone who wants to make a decision on sound scientific/enginneering data rather than on conflicting backyard mechanic anecdotes? Is it because I'm female?

Gokumono

Either way, if CarolinaGirl fixes it or not, still be nice to hear what the universities say...
SO this thread seems to have a purpose... least does to me.

CarolinaGirl

<<This may not be causing too much harm now but in the end it will "probably" cost you more then than it will now.>>

That might be true IF the vehicle didn't already have 225k and many other issues. Or it might not be true at all.

While there can be some difference between field vs lab (I have a degree/background in both field and lab science) the science is ths same. Am I the only one who want to understand the science of it?


I was told that it would suck in cold air, but that doesn't make sense to me because hot gasses expand. Someone else said it would onlybe a problem on trips. Why? If it has to do with compression issues, that would make sense to me. My personal mechanic said he didn't know if it would cause problems in 700, 7000 or 70,000 miles (and I really doubt it would last 70k more). I have passed 700 and 7000 so i'd like to find out more about why it didn't cause problems already etc.

I'm glad my mechanic is not a "if it's broke, fix-it" guy but also wants to know the why's behind it all.

Lumpy

Female has nothing to do with it first off. I like the ladies that can turn a wrench, nothing wrong with that at all.

I was interested in what the lab tests would have been...I would trust a mechanic more than a lab test in these examples though. Real world experience goes a long way in my book. This is why I'm on this forum...

I'm sure a small leak will not kill the engine, depending on where it is. My thing is it's not right so fix it. Eventually it will cause more of an issue so take care of it now.

yes I have let things go that should have been fixed and it cost me more in the end.

Ironmike4x4

Short and long of it, yes it can and will damage the valves. Depending on where the crack is you can temporarily get by with JB steel weld. I've done it myself but remember it will expand and contract continuosly. I did this on an s10 blazer I had and it worked for about a year until the jb weld finally fell apart and gave way to an even bigger crack. I wound up selling it anyways so I didn't replace it.

CarolinaGirl

Ok this is my last post since no one is providing any useful info.

14 yrs ago the roofing experts all told me I needed a new roof. I assume that was based on their expertise in the field. (I've roofed a building myself before, but being a very steep pitch, I didn't feel like doing this one.) However, I based my decision on whether the roof was leaking (ie causing damage or likely to cause damage in near future). It wasn't--and hasn't in the last 14yrs, even after taking a direct hit from a hurricane, a huge ice storm,and a few storms. If I'd made my decision only on "field" advice, I'd have been out $5k--money that I spent on this car, which replaced two totalled in the hurricane.

toyota4x4907

I can see how it can suck air into the exhaust.
Yes the gas has expanded, but its entering the exhaust and is cooling down, so its "shrinking". Plus, its moving, which causes a lower pressure. Its moving faster than the air outside the crack, so you get the Venturi affect, sucking colder air into the exhaust. (PAIR system anyone? ) Thats how I view it. May be wrong, but it makes sense to me.

Ironmike4x4

I see what you are saying Carolina Girl. In MY professional opinion it would depend on where it's located. If it's actually on the exhaust manifold then it would be a good idea to replace it. In my line of work I get paid to fix the problem, not jury rig it. In the case of the roof, you may have had a dishonest "expert" or they saw something that could potentially cause a problem. My best example of one is a repair I did awhile back. Customer comes in with a check engine light. It wound up being an HO2 sensor, when I checked the parameters it showed B1S1 was reading lazy, BUT B2S1 was on the verge of failing as well and I recommended replacing both. The customer only wanted to fix the CEL, I made them sign a waiver saying I was not responsible if the other O2 sensor failed. Sure enough in a matter of weeks they were back with a CEL. I checked the history ticket and thankfully I had written down my concern of the other O2 sensor and it was the problem. It amazes me how they went from being pissed off to utterly embarrased when I covered my own butt in that case. Which I relay back to my point. It's a potential problem. If the crack isn't really bad then I would maybe use JB weld in place but it's only a band aid to a true problem.

Lumpy

I'll buy that for a dollar...

Ironmike4x4

As far as "engineers and "scientists" there are no replacements for real world situations. In the lab the Titanic was "unsinkable" what happened there? How many recalls are there on vehicles due to engineering faults? I'm not trying to make an argument here, I'm just going by my professional experiences and opinions and hopefully make someone make an informed decision.

P.S. the cold air sucking in would be caused by both atomospheric pressures as well as the "pulsing" of the engine in between strokes.