Leaking Turbo Gasket and Gas Mileage Advice

[MichaelU295]

I found a leak between the exhaust manifold and turbo. I put my finger there and felt the hot air escaping while the engine is running. It missed one stud/bold there. There is only 3 left instead of 4. Is it a show stopper and have to be addressed immediately?

In the other hand, my gas millage is only average about 7mpg during 7,500 miles. Is it normal or I have to look further into the engine condition.

I only have my RV for a year and it is 1997 HR Navigator with Cummins mechanical 8.3 325 hp.

Please advise.

Thanks.

[Skip426]

Exhaust leak before the turbo will effect power , FUEL mileage , and exhaust brake performance.
Get to the repair as soon as possible.
Fuel mileage can vary 20% between drivers of the same vehicle .
Speed , rate of acceleration , and routes all will bring mileage down.
I consider 7 MPG a little on the low side , but you'd need input from someone with the exact same engine/trans and coach weight.
Do you tow a vehicle behind the coach?

[tom chelbana]

We had a 1995 Newmar London Aire which would be about the same weight and engine and we usually got 8 MPG. Do need to get turbo leak fixed to get true performance. Not good to have hot exhaust gas coming into engine area. Could cause a fire and the fumes could get in to coach.
Newmar Man

[MichaelU295]

Update:
I fixed the turbo gasket leak. The gas mileage seems to be at 8mpg now. Beside Tom Chelbana having 8mpg, our members here with similar engine/coach reported ~10mpg. I believe that low on gas mileage indicates some possible engine mechanical issue.

Where should I look further? My turbo boost only show max at 20psi, is it ok?

Thanks,
Michael

1997 HR Navigator, Cummins Mechanical 8.3 325 hp, Approx. 31,000 Lbs

[Sacer Turbo]

getting to the repair is a good advice.