dakota exhaust manifold bolts breaking

how many people having this problem with their 3.9L engines? mines a 99 and it blew the heads off the rusty bolts at 88000kms. the dealer here thinks i am going to pay him $1000 to fix this.

Reply to
mr burns
Loading thread data ...

And he will be right if you have him do the work.

Reply to
TBone

I have done it twice in 197,000 miles

Reply to
Billy

did you do it yourself? or what did the dealer charge you?

Reply to
mr burns

I did it my self, but I was lucky. none of the broken bolts were flush with the head. i.e. their was some bolt sticking out to grip and work them out.

don't use exhaust gaskets, I did the first time, nothing but trouble. just clean the head and manifold good. make sure they are flush with each other when you reassemble. first time I used OEM bolts. last time I used grade 8 black from hardware store, still holding.

Reply to
Billy

thanks billy, think mine is flush with the head. may try to drill it out next summer. it doesn't bother me that much for noise. a friend told me i would cause the cylinder to lean out, which i can't understand?? it is the exhaust manifold after all.

brian

Reply to
mr burns

Well, yes, but also remember the engine was designed to operate with a certain amount of backpressure. With the exhaust leak, you've lowered backpressure, which will let some of the A/F mixture escape during the time the valves are overlapped. The lower the RPMs, the more pronounced the effect of reduced backpressure.

Reply to
Tom Lawrence

Also a manifold leak will draw in outside air as the exhaust pulses go thru the manifold. The oxygen sensor will pick up this extra oxygen and richen up mixture to the point you could get a fault code.

Denny

Reply to
Denny

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.