anyone good with GM 3.1L engines?

[sumone]

basically my lower intake manifold gasket is leaking coolant...and basically with info from n-body.net, if that gets worse it could get into the oil and cause a whole batch of other problems. so anybody near know how to replace the gasket. All places I've called want at least 500...

...I do plan on keeping the car...

They say this is the reason why I get 14-15 MPG (and I've had a tuneup, new belt, and fuel filter replacement within the past two weeks) and this has been happening for the last 4-5 months or so.

(2000 malibu; 69k miles)

[1972ChevyGuy]

Our 90 Lumina has the 3.1 in it. The 3.1s are very prone to blowing intake/headgaskets.... It isnt TOO bad to replace them, but I have been working on cars since I was a tot.

I dont think it will get into the oil, only leak coolant. Honestly it SHOULDNT be any worse mpg but is it running hot?

The intake is pretty straight foward to take off, a few bolts and its done. Lift it just enough to get the old gasket off, scrape it real good to make sure its clean and the old gasket is totally gone. I personally use blue RTV sealant rather than gaskets these days but you can use a gasket without a problem. The intake bolts must be torqued to a certain ft/lb. Do you have a hayes manual or similar? They are REALLY great for the do-it-yourselfers. It gives a good breakdown of all the parts. A torque wrench would come in mighty handy also.

[sumone]

I dont think it will get into the oil, only leak coolant. Honestly it SHOULDNT be any worse mpg but is it running hot?

I have to refill the coolant every month or so. One time when I didn't refill the coolant for 2 months, the temp. gauge'd go into the red zone a lot until I remembered I forgot to refill the coolant the month before. What is hot? I'm running at about one notch above the halfway mark.

The intake is pretty straight foward to take off, a few bolts and its done. Lift it just enough to get the old gasket off, scrape it real good to make sure its clean and the old gasket is totally gone. I personally use blue RTV sealant rather than gaskets these days but you can use a gasket without a problem.

yea that sounds real simple....but you're talking to someone who didn't give a **** about cars only months after I started driving (which was less than 8 months ago). so it's all foreign to me if it's dealing with the mechanical parts of the car.

Do you have a hayes manual or similar? They are REALLY great for the do-it-yourselfers. It gives a good breakdown of all the parts. A torque wrench would come in mighty handy also.

1. manual? nope.
2. torque wrench...don't know what it is...but I have a regular wrench

so you're saying that a leaking gasket wouldn't cause low gas mileage???? NO!!! I've been searching for the longest for what is causing me to get low gas mileage. And when the mechanic told me the intake gasket was leaking and he said it could attribute to a low MPG, I thought that was *it*. however, the gasket replacement thing is something that still needs to be done.

...2 weeks ago I got a tuneup, and then tuesday of this week I had the belt & fuel filter replaced. still low, but improved, MPG (acceleration feels smoother too).

so I guess my real question was:
a - is there someone who'd do it for me for a reasonable price
b - OR, which I highly doubt, someone that'll tell me EXACTLY what to do step by step
c - OR, or any places that you could refer me to

[Shyne151]

pick up a haynes manual and replace it. i had to do mine, it isn't that bad.

[Shyne151]

Might as well replace your water pump to, that is an easy one... and they are only like $25.

[skeptikal]

my 1998 Lumina is a P.O.S., the battery is under the windshield wiper fluid, which in turn is under the strut bar, and to get to the sidemount terminals you have to move the air filter out of the way... Way to go GM on fukin car audio people over.... anyways to your thing.

low gas mileage on my car is usually caused by....

Lack of oil change, dirty air filter, dirty PCV valve, fuel filter, oil filter, maybe fuel pump but i doubt it. I have had the Oil and air filter replaced last week, the oil changed along with the PCV valve (worthless piece of shyt). cost me about 120$ at jiffy lube to have everything done i needed to do... but that is usually what gives my 3.1 bad gas mileage

[JimJ]

heh, i count myself lucky if i get 15 mpg...

but that's with a 4.9L 6cyl pushing a whole lot more in air resistance...

[sumone]

pick up a haynes manual and replace it. i had to do mine, it isn't that bad.

...yea, but how auto-inclined are you? I'm next to almost-none.

Lack of oil change

did that with the tuneup 2 weeks ago

dirty air filter

replaced 3 months ago

dirty PCV valve

replaced 3 months ago

fuel filter

replaced 3 days ago

oil filter

replaced 2 weeks ago

maybe fuel pump but i doubt it.

...hmm...don't think I've done that...

but that is usually what gives my 3.1 bad gas mileage

how many miles are you at?

...anyways, I went ahead and dropped the car off at the shop.
total cost: $670 for intake gasket replacement, parts for intake gasket, and water pump replacement. bought the water pump & parts for $29...so really, my total cost is $700. There goes todays paycheck & me borrowing 200 dollars from anyone I know...

[wErd]

$29 for a water pump?

[1972ChevyGuy]

Yes Werd, W pumps here are 35 bucks, as well as starters for a reman'd delco.

The haynes book is the best thing you could buy, it has all your cars specs in it. It even gives a step by step method with pictures to rebuild your motor.

Most cars have thermostats ~190 (170-210) or somewhere in that range. Most people will agree that ~190 degrees is optimal temp. Hottest I would ever dare run a motor with 50/50 antifreeze/water is probably 230, and that high I'd be getting worried. The only way low coolant COULD cause bad milage is if the block and heads are getting so hot that it is vaporlocking the fuel as it goes into the combustion chamber... so pretty much it dont affect it.

Btw, a torque wrench is pretty much like a regular socket wrench but it has variable settings so you can adjust how tight the bolts get. IE - 20 ft lbs, 50 ft lbs, 80 ft lbs.....

[sumone]

well, even though I let a shop do it, I bought both of those books - the haynes & the chilton.

...how bought bad gas mileage if the gasket is cracked or something by the gasket is cracked? my uncle was telling me to make sure that when they replace it, they the head or something isn't cracked otherwise that's bad.

[jellyfish420]

Our 90 Lumina has the 3.1 in it. The 3.1s are very prone to blowing intake/headgaskets.... It isnt TOO bad to replace them, but I have been working on cars since I was a tot.

I dont think it will get into the oil, only leak coolant. Honestly it SHOULDNT be any worse mpg but is it running hot?

The intake is pretty straight foward to take off, a few bolts and its done. Lift it just enough to get the old gasket off, scrape it real good to make sure its clean and the old gasket is totally gone. I personally use blue RTV sealant rather than gaskets these days but you can use a gasket without a problem. The intake bolts must be torqued to a certain ft/lb. Do you have a hayes manual or similar? They are REALLY great for the do-it-yourselfers. It gives a good breakdown of all the parts. A torque wrench would come in mighty handy also.

yes the coolant WILL get into the oil, it will coat the water jacket and you will ruin your block!

[1972ChevyGuy]

When you overheat, you run the risk of cracking the block/heads. If you have a blown headgasket it runs very rough, almost not at all. The only real good way to check a block or heads for cracks is to dip and magnaflux them. But that can run a little expensive sometimes. Unless you drive around everyday with the temp gauge pegged, you more than likely dont have a crack.

[jellyfish420]

you need to start doing stuff yourself. i do all my own work, and it saves so much money. not only does it save labor charges, but you don't have anyone trying to sell you stuff that isn't really broken.

[sumone]

^ x2. I'm starting off with the small stuff...I did see how the guy replaced the water pump, and that was definitely something I could've done myself.

but, I guess you were right. They replaced the pump & all gaskets in the engine; Temperature gauge still runs at the same area (a little above halfway), which I didn't know if that would change. The area around the gasket still looks clean (aka no coolant leaking), HOWEVER, I still get low mileage!!!!!!