Is the 1993 3.9L V-6 an Interference Engine? In other words, if the the timing chain fails do the pistons cream the valves and wreck the engine? Please let me know.

Thanks,
Purma

 

Yes. Did you kill your timing chain?

 

To Crazy:

Thanks! Are you sure? How do you know this?

I have a coolant leak from the timing cover and was wondering if after 18 yrs and 107k miles I should also have the timing chain replaced while they're in there. I only drive the truck a few hundred miles/yr at this point and don't know how much longer I'll keep it, but if you are correct that it is an interference engine I'll probably have them replace the chain while they're at it.

Purma

 

90% of all engines in vehicles uses a chain or belt and it it brakes the pistons can hit the valves that are open and bend them. But some engines get lucky that it doesn't happen like that.

Yes have it replaced, cheep insurance.

 

Not many non-interference engines on the market. These are definately interference style though. I think they are around .125" on the exhaust side during normal operation. Hence, the .509 +/- .005 for cams on stock heads. Even then, you should putty them for clearance checking.