Basic 3100/tranny removal questions

[SteveInMs]

Hi everyone, new to the forum. Sorry if this topic is listed elsewhere, if it is I couldn’t find it

I’ve bought a project car, a 1998 Malibu with a blown engine. The motor is seized. Along with the purchase of the car the owner also threw in a supposedly good replacement 3100 and tranny, which I’m not sure what year or model car it came from. I see the tranny filler cap on the Malibu is red, the replacement tranny has a bigger black rubber cap.

The repair was started by someone else who seemed to be attempting to pull the entire engine/transaxle, so I guess that’s what I’m going to try as opposed to removing only the motor, since I’m not sure they will bolt up, though they look like they will. He pulled all the wires, harnesses, unbolted the exhaust, etc.

I have plenty of experience pulling RWD drivetrains, but this will be my first at FWD. I know I’ll have to remove the wheels, CV joints, etc. Is there anything else I should know? Any input would be greatly appreciated!

Steve

[SteveInMs]

I'm only getting an hour here and there to poke around with this car. Today after pulling the spark plugs and attempting to budge the crank, it moved. In fact it turns 360 with no apparent obstructions so I'm going to make an attempt to hook everything back up and try to spin it over with the starter.

[mobileaudio219]

Those cars are really bad about blowing the lower intake gasket (and sometimes head gaskets), it probably filled the cyl full of water and hydro locked it... When you pulled the plugs it allowed it to pump the water out, thus turn over...

Check the oil and see if it looks milky!!!

[SteveInMs]

Those cars are really bad about blowing the lower intake gasket (and sometimes head gaskets), it probably filled the cyl full of water and hydro locked it... When you pulled the plugs it allowed it to pump the water out, thus turn over...

Check the oil and see if it looks milky!!!

I think you're right, and thanks for responding!

The oil wasn't milky, but there was water in at least two of the cylinders.

I threw a battery in, hit the starter, and took a compression check. Most were in the 180-210 range except #5, it was 40. I didn't hold them very long, but they all seemed to be holding their respective pressures at least for 30 seconds or so. I pulled the heads and found water in 3 and 5. I could not see anything wrong with the head gasket, though I admit I wasn't looking too hard. I do know there were no breaks in the metal cylinder "rings" in the gasket.

The lower intake looked to have possibly leaked water though, also hard to say. I was pretty tired of the whole thing by the time I got to pulling heads off so I didn't do a very thorough job of looking for cracks in the head, and how the heck would I find a crack in the block unless it was very obvious?

I have a 2005 3100 (it has a 4T60E still attached). I'm wondering how hard it would be to just yank what's left of the bad motor out of the car and put the newer 3100 in. Are there any differences in the 1998 and 2005 3100s? Also, from what I've read using the 4T60E would be a problem since it wouldn't be electronically compatible with the 1998 Malibu. Do you know if that's true?

Steve

[mobileaudio219]

The water in the cyls could be from a leaky intake gasket.

Low compression could be from a few things. I'd check the head gasket, head, make sure the valves are seating correctly, then check the cyl themself... and the rings.

Low compression between two joining cylinders usually is a head gasket or cracked head...

Since it sounds like you dont know the history of the engine, I recommend switching it out. Water can do some major damage to the bearings, which means pulling the engine apart for a rebuild...

It'd cost about 800 to rebuild the engine (crank polished, new main/rod/cam bearings, cyl honed, new rings, timing chain, oil pump, heads redone, water pump, all new gaskets.)

I'd personally try finding a low milage 3400 and swap it in..

As for the transmission? I dont think it'll work... Did you smell the fluid in the car to see if it smells burnt? That would tell you alot...

[SteveInMs]

Since it sounds like you dont know the history of the engine, I recommend switching it out. Water can do some major damage to the bearings, which means pulling the engine apart for a rebuild...

As for the transmission? I dont think it'll work... Did you smell the fluid in the car to see if it smells burnt? That would tell you alot...

Yes, fluid didn't smell burnt, didn't look burnt either (brownish-red). Being totally ignorant about these cars, I've just learned the 4T40E has no dipstick and the 4T60E does, so I'm learning more everyday...

The most logical direction (at this point) is to switch it out with the other 3100 after some basic testing to make sure it's not DOA either and hope the tranny isn't junk.

There's no way I know of to test an automatic. A 3400 would be cool, but it's destined to be a commuter.

[mobileaudio219]

Yes, fluid didn't smell burnt, didn't look burnt either (brownish-red). Being totally ignorant about these cars, I've just learned the 4T40E has no dipstick and the 4T60E does, so I'm learning more everyday...

The most logical direction (at this point) is to switch it out with the other 3100 after some basic testing to make sure it's not DOA either and hope the tranny isn't junk.

There's no way I know of to test an automatic. A 3400 would be cool, but it's destined to be a commuter.

These motors are pretty good motor once you get past the gasket(s) problem...

Pull the plugs out of the new motor, bolt the starter on and crank it over with the starter to check the compression...

If the compression is good on all cyls, I'd probably go ahead and replace the lower intake gasket and slap it in...

[SteveInMs]

If the compression is good on all cyls, I'd probably go ahead and replace the lower intake gasket and slap it in...

Replace the lower intake gasket even if the compression is good all around?

[mobileaudio219]

I would... The intake gaskets are literally that bad in these cars, its easier to do with the engine out already...

[SteveInMs]

I would... The intake gaskets are literally that bad in these cars, its easier to do with the engine out already...

Gotcha. I guess the next step is to yank the bad motor out. May have to wait a few days, catch up on other stuff.

I really do appreciate your input, it's helped out a lot.

Thanks

Steve

[SteveInMs]

btw, I'm not sure, but I think the replacement motor is an LG8. I can't prove it, but tag on the tranny reads 2005 and from pics it looks like an LG8 (maybe)

[SteveInMs]

Well, went home and found the casting # on the block of the one out of the car... it's 10137093.... and older 3100, probably with the same problems. Now I'm thinking about just fixing the one in the car (new LIM gaskets, head gaskets) and the nightmare of trying to figure out which electrical connections go where.

[mobileaudio219]

Well, went home and found the casting # on the block of the one out of the car... it's 10137093.... and older 3100, probably with the same problems. Now I'm thinking about just fixing the one in the car (new LIM gaskets, head gaskets) and the nightmare of trying to figure out which electrical connections go where.

I was in the same boat as you, bought a 96 monte with a blown head gasket. The motor still ran, but I didnt want to risk a bearing failure later down the road so I yanked it out...

I was orginally going to rebuild the orginal motor, but I just bought a 3100 with 88,000 miles on it for $250..

I wish you the best of luck,...It may turn out fine, or it may not... It's iffy!