Went out in Jeep for a 60 mile run at the weekend no canvas on, came back stinking of exhaust fumes. Recently changed out exhaust gaskets on manifold which have no signs of blow by. Also have tailpipe downward facing under the bumperette, behind rear tyre I do need to change the gasket attaching tailpipe to muffler as it did show evidence of a small amount of blow by. Muffler to main exhaust pipe fine no evidence of blowing there.
Mrs Jackson not best pleased her clothes and air have a whiff of exhaust fumes .
Is there anything else I can check? Is this a common issue with M38a1s?
Is there any thing else to try to alleviate the issue.
Thank You
Fairly common with any open jeep. Gets worse if the engine is running to rich or burning oil. Remember when the US Army asked for an off road open bodied military transport in 1940 they never planned on a sustained operational speed above 45MPH so Willys, Bantam and Ford all came up with the basic short wheelbase open vehicle design that has stayed with us the last 4 decades. The old tiny range rover when operated topless can do the same thing.
They are nowhere aerodynamic. Exhaust fumes probably being pulled forward from the rear while moving down the road.
You’ve seen the fancy fairings on the rear of big rig trailers? They are designed to reduce the air being sucked into the rear of the trailer creating drag. Same suction on the jeep is pulling the exhaust forward.
The easiest way is to get one of the exhaust extension pipes
WO-811293
used with the M170, which is also offered by many dealers for the M38 and M38A1.
This part can make a big difference, as the exhaust is no longer swirled by the bumper.