Opinions on the 3.1 V6

I have a 94 Grand Prix with 175,000 miles on it and am selling it used tomorrow. Problems with this engine were minamal. It did have the green stuff for coolant. Great engine in my book.

Now I have a 3.1 in my Monte Carlo 1999 with the red coolant. Had to have a head gasket ($475.00) done at 82,000 miles. GRRRRRRR!

I think it's a good engine when maintained.

Oil: my car is usually between 70 and 115 degrees F outside air temp, so I use 10w30. If it gets cold where you are, then stick with 5w30. Coolant: use the green stuff. Engine: uses a chain. Change every 250,000 miles. More often if you use your car for racing. Engine: 60 degree engine is a very poor design. It seems that about half of the 3.1's made need intake manifold gaskets every 60k miles. Look very carefully all around the intake for telltale leaks and/or antifreeze residue. Check the oil for water/sludge.

I just gave up on trying to wear mine out; It had 172,000 miles on it and still going strong, with the original transmission. It fried the ignition brain board a couple times, but no other problems.

I for one am real impressed with this engine. My '91 GP with the 3.1 has been great. I had a head gasket go out on it at about 80,000 mi. Mechanic found that one of the head bolts was broke causing a weak spot in the head. I don't blame the engine for that. Possible bad bolt or over torqued at the beginning. I have 135,000 mi on it now and still runs like a champ. Keep on top of the maintenance and don't let it over heat. This engine has the timing chain, I've all ways used the green coolant, and use the 5-30 oil. Doesn't use any oil and have been getting 32-34 mpg on road trips.

Tom

I have a 97 GA with about 107k miles, to be honest it pretty much runs like new. Beware of intake gasket failures at about 100k miles causing coolant leak at the engine. Its an expensive repair. Its a gasket that connects the coolant sys to the engine. I cost about $800 to fix, I think the fuel injection, throttle body and other engine parts need to be removed to get to the repair which makes ir expensive to fix.

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Assuming you don't have serious oil consumption problems, stick with

5w-30.

Green works fine. Change it every two years though.

Chain. No need for periodic maintenance.

Keep a close eye out for coolant leeking into the engine. Sign of a poorly designed lower intake maniforld gasket setup.

GM didnt start using dexcool until about 95 on cars. Lets make it clear,=20 if it has dexcool do not switch from dexcool. If it has the green based=20 coolant do not attempt to switch to dexcool for the residue left over from= =20 the green coolant will only contaminate dexcool.=20

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-Bon=B7ne=B7ville

-Formerly known as

-Bonnevilles R Kewl

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Keep an eye on the upper and lower intake manifold gaskets for leaks.

I can beat one with a 2.5 if you don't pay attention. 3.5 Chrysler is overrated on an aside if you ask me.

Hmmm I'm only getting this one message for the whole thread...

If these questions have been answered already, my apologies.

The 3.1 has a timing chain. 5w-30 would still be fine for this engine.

My '90 Grand Prix with 3.1 has over 200,000 miles and it's still runs very well. It has the original timing chain.

I've got 225,000 on my transport with a 3.1. I change the oil maybe every

30,000 to 40,000 miles or so. Some times I just add 2 or 3 quarts when I go around corners and the oil light flickers on. What I guess I'm saying is that I beat this minivan but it just keeps running. The engine (short block) was replaced at about 65,000 miles because of a recall for piston slap. But I would highly recomend the 3.1. The 3.8 in my bonneville is a different story.

Glen

An oil change every 30,000 to 40,000 miles???? Did you make 2 typos and hit Zero one to many times there??? Thats like 10 times the number of miles you should go between oil changes! No wonder you need 3 quarts after making a turn! Man you valves guides, rings, and cylinder walls must be shot to hell and not to mention your catalytic converter!

I dont know what your gripe is about the 3.8 but it is a proven work horse so long as its "properly" maintained.

I hate crossposting but this was a shocker to me...

:o that's a lot of miles between changes! I guess the engine is tougher than I thought.

My mother had a '92 Corsica with 3.1 in it. She changed the oil about every

10-20 thousand miles. The engine did not last 200 thousand miles. In fact, it was rebuilt and sold to me. The engine still had a knock after being rebuilt (speaks to the quality of work, IMO). It didn't last 10 thousand miles for me (with regular maintenance). The crank broke in 2 places (on either side of #5) while I was cruising down the road at 60 MPH.

There's a shiny orange block sitting in the scrap heap... just needs a crank.

I guess I'm cheap. My 3.1 rattles and sounds like a diesel when it starts up,my a rod knocking, but after a couple of minutes when the oil starts taking up the gaps it sounds pretty good. Oil pressure shows 60 lbs. We took it on a 2000 mile vacation last summer. Next year may California (4000 miles). If it breaks down Call Enterprise car rental. They pick you up. Then I'll just have it towed to the junk yard. If you add 2 quarts when it's low, that's almost like an oil change.

Glen

Oh yah 3.8 is pretty good too, but that internal water leak that hydro locked up the engine because of gm's poor design didn't make me happy.

I hear the 3.3 is much better than the 3.1. Too bad it's getting hard to find. 170hp and 2mpg better than the 3800 isn't so bad considering that's just below(5hp) what the original 3800 put out.