My 1994 Concours with the Northstar runs great at 105,000 miles but I have been reading a lot about blown headgaskets and cracked blocks. How much longer can I expect from this engine before its doomsday? I always make sure coolant levels are good and look for leaks. Also is synthectic oil OK to use in this engine? Thanks

The HG may blow tomorrow or never blow. Change your coolant every 2-3 years... if your not having to add coolant between changes or it's not overheating don't worry about it. What you see on this board is people that are having problems... all the people out driving around problem free aren't posting on here. Use whatever oil you want as long as it's the correct weight calle out in your owners manual.

:yeah:......................:welcome:

Welcome. As stated, all you are seeing is the people with problems. The HG are an issue, but there are far more cars on the road that are trouble free than the ones pooping out. Its all luck of the draw. If you haven't had an issue at 105k miles I doubt you will ever have one.

I also have paranoia issues :hide: so I may as well latch them onto this thread as well. I noticed when doing my EGR job recently that the intake manifold is plastic on the 4.6 Northstar. Is it very common for these to crack and/or develop leaks. It appears to be of a very similar construction to the GM 3.1/3.4/3.8 intake which are notorious. Mine did have "96" written on it with yellow paint marker when I removed the top cover, and I'm kinda assuming that's not something that would have been done at the factory.

The manifolds are not a problem. What breaks is the bolt bosses when people try to exceed the 7 ft/lb (89 in/lb) torque specs. (Check yours - that's for a 2000+......................)

It appears to be of a very similar construction to the GM 3.1/3.4/3.8 intake which are notorious.
I cannot speak for the 3.1 or the 3.4, but the 3.8 manifold issues where the EGR "stove pipe" that vented into the manifold right behind the TB. It would get very hot and burn through the manifold. No such issue with the Northstar and I have rarely heard of one cracking unless it was over torqued.

Thanks for the re-assurance...I always get concerned when seeing plastic intake manifolds. I didn't even check for that when buying my car, it was so clean and run/drives great, the price was right, I just kind jumped right into it...