Exhaust Leak

Brian95SVT · Mar 11, 2008

Anyway to find out if I do have an exhaust leak?

If I start my car for the first time and let it sit for a few seconds then rev it, it starts to like freak out and bog and if i get underneath my car it sounds like an exhaust leak but then after a few seconds of freakin out it goes away then runs fine...

If I start the car and let it warm up it doesn't do it at all.....

STEEDA96 · Mar 14, 2008

since warming the engine up seems to stop it, i think it may be a manifold gasket. heat expands the seal, providing a better seal, but as it cools, the leak re-opens. Plus since the leak has such a dramatic affect on throttle i would expect it to be close to the engine. Never had this problem..just an assumption.

also..check eng light?

reivaxtorres · Mar 14, 2008

STEEDA96 said:
since warming the engine up seems to stop it, i think it may be a manifold gasket. heat expands the seal, providing a better seal, but as it cools, the leak re-opens. Plus since the leak has such a dramatic affect on throttle i would expect it to be close to the engine. Never had this problem..just an assumption.

also..check eng light?

pretty much what i was going to say.

and its somewhat easy to smell if you have an exhaust leak. can you smell any fumes under your car, or under your hood when you open it?

Brian95SVT · Mar 14, 2008

reivaxtorres said:
STEEDA96 said:

since warming the engine up seems to stop it, i think it may be a manifold gasket. heat expands the seal, providing a better seal, but as it cools, the leak re-opens. Plus since the leak has such a dramatic affect on throttle i would expect it to be close to the engine. Never had this problem..just an assumption.

also..check eng light?

Click to expand...

pretty much what i was going to say.

and its somewhat easy to smell if you have an exhaust leak. can you smell any fumes under your car, or under your hood when you open it?

No CEL, No fumes. Sometimes I get a little wiff of something but it's not like common.

STEEDA96 · Mar 14, 2008

im not one for just throwing parts at anything, but gaskets are like 10 bucks at LMR. cant hurt anything. otherwise id go over the whole exhaust system with a fine tooth comb and with the car well elevated. start it cold.

http://www.latemodelrestoration.com/products/Mustang-Exhaust-Gaskets

reivaxtorres · Mar 14, 2008

STEEDA96 said:
im not one for just throwing parts at anything, but gaskets are like 10 bucks at LMR. cant hurt anything. otherwise id go over the whole exhaust system with a fine tooth comb. not literally

the comb would melt....lol :hammer:

the gaskets may only be $10 each, but if we are talking the exhaust manifold gaskets (that go between the head and the manifolds), you need 4 of them, and its a PITA to change them.

check to make sure you dont have any openings on the intake side of the engine, like a loose intake tube, loose intake pipe, anything. just like heat affects the expansion of the metals for the manifolds, it has a funny way of doing the same to rubber.

Bluesn95 · Mar 14, 2008

Honestly doesnt sound like an exaust leak. My car used to be the exhaust leak king and I've never had anything close to what you described. I've had bad exhaust leaks in every place immaginable and never caused my engine to run rough. Sound like you have trash or air in fuel system. Maybe somekind of injector problem. Could also be a warped intake manifold that seals up once the engine warms up. Are you throwing any kink of engine codes?

STEEDA96 · Mar 14, 2008

have you replaced the manifold/plenum/Throttle Body?

Brian95SVT · Mar 14, 2008

Bluesn95 said:
Honestly doesnt sound like an exaust leak. My car used to be the exhaust leak king and I've never had anything close to what you described. I've had bad exhaust leaks in every place immaginable and never caused my engine to run rough. Sound like you have trash or air in fuel system. Maybe somekind of injector problem. Could also be a warped intake manifold that seals up once the engine warms up. Are you throwing any kink of engine codes?

already said no CEL

Brian95SVT · Mar 14, 2008

STEEDA96 said:
have you replaced the manifold/plenum/Throttle Body?

i have a PI intake

scarface · Mar 14, 2008

get a pair of gloves, start your car, cover both exhaust tip with your hands... If its leaking, you will hear it escaping from somewhere else.

Bluesn95 · Mar 14, 2008

Exhaust leaks don't cause the car to bog. I think your intake manifold is leaking. That manifold isn't designed to match up with that set of heads from what I understand although lots of people do it anyways.

Brian95SVT · Mar 14, 2008

I never said my car bogs... well i did i said when i FIRST started it COLD and just straight REVed it up it would start to like spudder ore of a "bog" and it looked like there was water drippin from underneath where one of the clamps are.
I think my intake is leakin antifreeze but its not a lot at all.. just a little.

Bluesn95 · Mar 14, 2008

That intake may be the problem. Did you put it on? Did you have to use a lot of rtv?

Brian95SVT · Mar 14, 2008

The shop that put my motor did but they aren't a "tuner shop" or anything, just a regular shop and I don't know if they did put it on there or not and I haven't had a chance to find out myself... kinda scared to do it...

Bluesn95 · Mar 14, 2008

I may be totally wrong but from what I understand is that without the pi heads the ports on the intake don't match up excatly and usually a lot of rtv silicone needs to be used. The problem with usuing a lot of this stuff is that eventually over time the rtv may actually be slightly sucked into one of the ports causing a sealing problem. When the engine warms everything up it may then make a better seal causing it to seem like the problem has gone away. Have a compression check done on your manifold. Cost is about 40 bucks but it will help u find or eliminate one of the possible problems. This is just my take on things.

Brian95SVT · Mar 14, 2008

hrm as far as i was aware you just use PI gaskets and it fixes the problem or ive even heard of an adapter but yeah
i will have look into that

just bring it to a local shop and ask for an intake compression test?

Bluesn95 · Mar 14, 2008

Yep any place that does moderate car repairs and isn't a hole in the wall should be able to do it. When my intake finally warped (thats a common problem with original npi intakes) I just took it to ford and they did it in about an hour and just like I thought my intake was leaking coolant because it had warped.

Brian95SVT · Mar 14, 2008

my NPI intake warped so we got a PI intake to replace it.

Bluesn95 · Mar 14, 2008

If the people that installed the pi intake didn't know that the intake you gave them wasn't original equipment on your car or didn't know the correct procedure for installing this particular intake they may have not used any high temp gasket maker at all causing your current problem. That just came to me.