Finding exhaust leak

[Eventoday]

Hello

I have a 1998 V90 with higher mileage.
It has a bit of a vibration when giving it gas.
I've checked all of the hoses for leaks, plugs are new
Throttle body is clean etc etc.

The vibration feels like what I would imagine an exhaust leak to feel like. So I figure, let's go with my intuition and look for a leak. The car is new to me so I don't have a reference if the car is louder than what it should be.

I've read, you can use a shop vac to blow air up the tailpipe, then spray soapy water around to look for leaks. Before I do that, I just wanted to get some advice to make sure you can't mess anything up doing that??

Also, I'm planning to take the heat shield off to access the exhaust manifold. From what I understand the manifold bolts themselves can break and strip out. I don't plan on removing them but I am curious about the heat shield bolts. Should I spray them for a couple of days beforehand? Do I need to worry about them breaking or stripping?

Kindly
Jake

[Paulk]

Have you checked the propshaft centre bearing?

[Eventoday]

Thanks for the reply.

I have not checked that.

Quick caveat, I also get the vibration in nuetral/ park.
The prop would not be spinning unless in gear correct?

[360beast]

The heatshield bolts will most likely snap.

What are the engine mounts like? Prop bearing wouldn't affect anything if sat still but work engine mounts would.

I check for an exhaust leak by getting a thick bit of rag and holding it over the tailpipe for a couple of seconds (it gets hot quickly). If it is blowing you will hear it chuffing out of the hole louder than normal due to the extra backpressure.

[Eventoday]

Thanks for your reply.

My first thought was the engine mounts. They look and feel good to me. I even had a mechanic who was working on my mini van give me his opinion. They also thought they looked good. I still have my suspicions of the mounts though. I tried to do the visual oil pan test to see if the mounts were sagging but couldn't quite figure out what I was looking for.

I really do not want to open a can of worms with the heat shield. Maybe I'll wait on checking the manifold gasket unyil I am able to check the rest of the exhaust and rule out the mounts.

Kindly


.

[Forrest]

The first place I would look for an exhaust leak would be the ball and socket joint between the cat and the middle section. I found this very problematic on mine until I fitted a complete new system including a new bracket on that joint.

[Eventoday]

I went ahead and reversed the shop vac and shot air into the tailpipe. I felt a lot of air coming out of the side of the muffler, in two different places, along the horizintal weld. I don't think that would be the cause of a vibration in my steering wheel / gas pedal though??

The rest of the pipe, and around the cat seemed good. I couldn't tell around the exhaust manifold as the heat shield is in the way. I tried to listen for air but the vac was to loud.

[Clan]

Originally Posted by Eventoday

Hello

I have a 1998 V90 with higher mileage.
It has a bit of a vibration when giving it gas.
I've checked all of the hoses for leaks, plugs are new
Throttle body is clean etc etc.

The vibration feels like what I would imagine an exhaust leak to feel like. So I figure, let's go with my intuition and look for a leak. The car is new to me so I don't have a reference if the car is louder than what it should be.

I've read, you can use a shop vac to blow air up the tailpipe, then spray soapy water around to look for leaks. Before I do that, I just wanted to get some advice to make sure you can't mess anything up doing that??

Also, I'm planning to take the heat shield off to access the exhaust manifold. From what I understand the manifold bolts themselves can break and strip out. I don't plan on removing them but I am curious about the heat shield bolts. Should I spray them for a couple of days beforehand? Do I need to worry about them breaking or stripping?

Kindly
Jake

The inlet manifold gasket can deteriorate on these, spray some brake cleaner around the area on each branch where bolted to the head and see if the engine note changes...