Hello Monte fans,

Need advice from an experienced mechanic on these 3800 iron block supercharged motors. My fiance, a member of this board has a 2004 blue monte carlo SS, which she dearly loves. She needs this thing up and going. Here's what I got:

1. Oil in the water. Been 2k since last oil change (supposedly).
2. Oil looks good, and smells OK, down one notch on dipstick but not parked fully level either. Can't be losing much.
3. Exhaust smells sweet.
4. Pulled plug, it looks pretty good considering its got about 125k on it. Yeah its the original plugs in the thing. One mechanic I took it to claimed that you had to drop the block to change the plugs. What an idiot.
5. Bought the car with 100k on the clock. It had that super dumbass brown gunk coolant stuff in it. Had the radiator flushed twice some time ago, got most of it out. Seemed to be fine after the flushes. But all the passages are coated.

From looking around the internet, it seems the 3800 motor just doesn't blow head gaskets. It looks like the intake and exhaust manifolds are poorly designed and cause leaks when the "brown gunk crap" coolant is put in there. Whats my best course of action here. The way I see it, I can:

1. Take it to a stealer and throw money at it and specify they change the exhaust and intake gaskets, and hope the mechanic knows what he's doing.
2. Line up the parts and try to fix it next weekend. Can an average shadetree mechanic get it done in a weekend with common hand tools/heat/? Also, Its unclear to me what parts I would need. I have no customized GM tools. No shop manual.
3. Any other way to pin down exactly what gasket is leaking?

TIA

 

Gaskets are no big thing to do really, you will need a torque wrench to torque them down properly, it is probably an issue with the LIM gasket, I haven't heard a whole lot or read a whole lot on issues with the gaskets so i'm not exactly sure which one it could be, but I know there were some issues with the plastic intake manifolds and gaskets going bad

 

Thats about my take on it.

 

someone that has dealt more with the 3800 will probably chime in here soon

 

Any help or opinions I can get greatly appreciated.

 

Most likely an LIM gasket. Do not drive it if your are getting coolant in the oil. Coolant is the worst thing you can do to an engine bearing.

 

With 125,000 miles on the car its probably a lower intake manifold gasket. Is she still driving it?

 

You are getting a "sweet smell" out the exhaust, that's head gasket. After the car sits over night and start it, does it run a little rough for a second? Any unusual clouds of white smoke?

Normally with a bad lower intake, you find coolant in the oil (gets milky) or you find loss of coolant (by going in the oil OR exiting the engine all together). Yes, the LIM gaskets are MORE common then head gaskets to go bad in the 3100/3400/3800 drive trains (nylon was a crappy gasket material, that's why, replace with aluminum gaskets).

You pulled one plug out, pull them ALL. Mark what cylinder each one came from. If the car is running 100% fine (not a bad head gasket), you will find all plugs should look identical. If you pull one or two that look "different", those are cylinders having a problem. It is possible for a head gasket to fail and only affect one or two (basically not all) cylinders. If fails in a way that permits coolant to travel from the water jacket to the nearest cylinder.

 

Roger that. If all the plugs look identical, would that make the LIM a good guess?

Car runs fine to me but I don't drive it everyday so I have nothing to compare it too, but it'll still take the throttle and the power level is still there, not as much as my (cough) ford 4.6 (cough). When I get time I'll pull all the plugs and see. Probably going to be next weekend.

There's definitely coolant loss. And its definitely going out the exhaust, I can smell it and thats new with this car. Car starts and runs like a champ from the beginning, no stumble. It must be a slow weep rather than a total failure. No billowing white smoke/steam.

There's nothing in the oil. I know exactly what water in oil looks like. There is oil in the coolant though along with coolant loss. Its enough to have left some slimy gobs of white goo right below the radiator cap.

And no, for all concerned, she's not driving the car (now that I know about the problem) .

I got into this thing because it was overheating from the coolant loss. I already tossed a thermostat on it, still getting hot, looked in the radiator like forrest gump and said...ain't got no water in there.

 

As a side note, the backup is a 99 monte z34 with about 215k on it. Been sitting for a year. After I got enough juice in the battery which took all day it fired right up.