Thoughts and experiences please - my 96 milli has 135K miles, but has the usual leaking valve covers and noisy valves which means its time for a valve job and rebuild. it blows a little blue smoke at startup, and some off throttle. What is the history and typical life of the bottom end for bearings, pistons rings and such. We hear no knocking or unsual noises with the stethascope, and there are no codes, passes smog easily in CA. Is a full rebuild recommended, or does the 2.5K v6 work with just a head off top rebuild? This car has been well maintained - regular oil and fluid changes, has recent wp - CV etc; usual consumables in its life.

Appreciate any comments or nuggets!

Thx

 

i have never owned a 2.5, but from all the posts, and our 2.3's, leaky valve cover gaskets is very common. the 2.5 has hydraulic lifters, if they are noisy, you should at first try an additive to quiet them. i have not seen but 1 or 2 posts about a bad bottom end, and iirc, those were thrown rod posts. when i was in the shop, we used a product by BG called motor purge. one qt, you change oil, add the mp and fresh oil, then run the engine at high rpm(1200) for an hour. it will smoke like no tomorrow. then you drain, and add fresh oil and filter. results were generally amazing, esp compression. it wont do anything for valve seals, tho. you should try some of the new hi mileage oils, valvoline maxlife comes to mind. i had several people tell me that oil consumption dropped dramatically after switching to maxlife.

 

You can do an in car overhaul on that one. The most common hard part damage is generally the left front cam/head journal. If thats ok and the rear main is not leaking i would pull the heads and pop the pistons out with the engine in the car and just roll new main bearings in. The heads i would let a machine shop rebuild.

 

I just did mine a week ago. I took the heads to the machine shop and had them checked out, pressure tested, valves reseated, changed the valve seals. As for the bottom end, my 2.5KL engine was not smoking but I went ahead and changed the piston rings and the rod bearing myself with out taking the block out of the car. In your case, you stated that you see a little smoke. I think you have some bad piston rings and you should definately do the bottom. I only spent an extra $100 for the parts and it took me one afternoon to replace. Get stock size piston rings and be sure not to hone the piston chambers, this will then require you to get all technical into it and measure for proper piston ring clearance. If you just sand the inside of the piston chamber with fine sand paper you will be alright. I bought the gasket kit on ebay for a few bucks which included the head gaskets, valve cover gaskets and gromits, intake manifold plenum gaskets, valve seals, pretty much all you need. good luck, let me know if you want more info on my experience doing it. Jim