Car question

[driver145]

This is for people that know more about cars than me.

I have been working on my car little each day for like two weeks now... and finally got the cylinder head off (well on one side). I was just wondering, is there anything else I should check while I have the engine taken apart?

It is a 3.1L v6 Chevy Monte Carlo (1999). I blew the lower intake manifold for sure. I think I blew the head gasket because there was milky chunky stuff in the oil. I have taken off the front gasket so far and it was not destroyed, but you could see where it had been overheated and there were traces of oil/coolant/liquid between the gasket and metal surfaces.

Thanks for any help. Before this task, the most I had done to a car was just a tune-up.

P.S. I miss working on 4 cylinder hondas....

 

[OneTrack]

It's very important to diagnose WHY your motor over-heated.
I would suggest removing BOTH cylinder heads and having them pressure tested and resurfaced. I don't know if GM had any issues with cracking cylinder heads (or cylinder block..?), but it would certainly be a good precaution to have them checked.
Also, get your radiator out and have it flushed, inspected for flow/blockage and also pressure tested.
There are a few other items you should check visually (surfaces of block under the head gasket, condition of hoses, thermostat, etc), but do these two things at the very least while you've got it apart.

 

[dako81]

+1 OneTrack

Sorry about your gaskets. Turn your motor over and check the cylinder walls for piston slap. Do a search on google for 3.1L pistion slap and learn about it. That would be something I would check if you already have it apart.

 

[driver145]

Just to give you some more info. These motors are notorious for leaking intake manifolds. I had the coolant flushed and it began leaking immediately afterwards. I had the bike and did not care about the car much (I hate this car), so I just kept topping off the fluid. I think I let it get low a few too many times. It had overheated twice because of low coolant (with less than a minute of running after the HOT light came on), before any major problems started. Then it just would not stay cool, even though it had coolant in it, and then I realized that the oil had milky crap in it.

I am changing the water pump and thermostat, and I ran it before I took it apart with a new water pump and it seemed to circulate the coolant just fine, but would still overheat eventually.

 

[JeffrosFZ6]

+1 one the leaking intake manifold gaskets. Im a tech for Chevrolet (20+ years) and the 3.1 and 3.4 liter v-6s all have the same problem. The lower intake manifold gaskets leaking coolant externally and internally (into the engine oil causing the milky substance). If you catch it quick enough, change the gaskets and change the oil it will be ok. If its driven awhile with the coolant in the oil - time for a new engine. The coolant (not a lubricant) will destroy the bearings, lifters, etc.
fyi my .02

 

[driver145]

+1 one the leaking intake manifold gaskets. Im a tech for Chevrolet (20+ years) and the 3.1 and 3.4 liter v-6s all have the same problem. The lower intake manifold gaskets leaking coolant externally and internally (into the engine oil causing the milky substance). If you catch it quick enough, change the gaskets and change the oil it will be ok. If its driven awhile with the coolant in the oil - time for a new engine. The coolant (not a lubricant) will destroy the bearings, lifters, etc.
fyi my .02

I wonder if the engine is still good... I did not realize that the lower intake manifold leaking would also cause coolant in the oil. It would still run... it would just get hot real quick and overheat after running for more than a few minutes.

I will probably just fix it and sell it, anyhow. I just hope all this work isn't futile.

 

[Tailgate]

Feel fortunate that what you're working on isn't a van. It sucks to have to work on an engine that is enclosed in a van. Everything is harder to get to, harder to see, harder to pull. It totally sucks when it comes to working on an van engine. I had to (well, actually it wasn't necessary..I subsequently found out) remove a head and it was probably twice the work than if it had been a "normal" under hood engine.

 

[driver145]

Feel fortunate that what you're working on isn't a van. It sucks to have to work on an engine that is enclosed in a van. Everything is harder to get to, harder to see, harder to pull. It totally sucks when it comes to working on an van engine. I had to (well, actually it wasn't necessary..I subsequently found out) remove a head and it was probably twice the work than if it had been a "normal" under hood engine.

Fair enough. Luckily, I refuse to ever own a van.


(That smiley face is kind of "gay", but I think out of the ones available it most accurately captures my childish attitude in the above remark)

 

[OneTrack]

+1 one the leaking intake manifold gaskets. Im a tech for Chevrolet (20+ years) and the 3.1 and 3.4 liter v-6s all have the same problem. The lower intake manifold gaskets leaking coolant externally and internally (into the engine oil causing the milky substance). If you catch it quick enough, change the gaskets and change the oil it will be ok. If its driven awhile with the coolant in the oil - time for a new engine. The coolant (not a lubricant) will destroy the bearings, lifters, etc.
fyi my .02

Great info! :thumbup:
JOOC, is this the same motor that was rear wheel drive Astro Van?
If so, I've got some bad news for my cheap brother-in-law.

 

[HavBlue]

Great info! :thumbup:
JOOC, is this the same motor that was rear wheel drive Astro Van?
If so, I've got some bad news for my cheap brother-in-law.

No, the M van (Astro) which began life in 1985 had a 4.3L V6 which was basically a chopped up 350.

 

[wolfc70]

Yes the GM 2.8, 3.1, and 3.4 all had lower intake gasket issues, at least all of mine did. Most likely the head gaskets are fine, I boiled my 3.1 once due to a non working rad fan, and it never went. The milky substance in the oil is coolant getting in the oil. It ran hot due to air in the cooling system, as they can be a pain to bleed, especially if you have a slow leak. How long was the coolant in the oil? If the gasket was leaking for a while, drop the oil pan and plastigauge the bearings. This is usually where any wear occurs when coolant dilutes the oil. I would do this before pulling the other head, to see if a rebuild is necessary.

 

[madmanmaigret]

I dont know much about these GM motors but considering the age of the car how about timing belt/chain? Do they ever need to be replaced? (I know honda's more than anything) might be a good time to check that out also.

 

[wolfc70]

I dont know much about these GM motors but considering the age of the car how about timing belt/chain? Do they ever need to be replaced? (I know honda's more than anything) might be a good time to check that out also.

This is a pushrod motor, so the cam is in the engine block, nestled below the "vee". There is a chain that drives the cam, and even after 160K miles, my 3.1 was still good, hardly any slack. Too bad everything else was worn out on the engine.

 

[madmanmaigret]

This is a pushrod motor, so the cam is in the engine block, nestled below the "vee". There is a chain that drives the cam, and even after 160K miles, my 3.1 was still good, hardly any slack. Too bad everything else was worn out on the engine.

sweet, wasn't sure if it was ohc or pushrod. thanks. I still cant figure out why honda has to use timing belts. chains are better

 

[wolfc70]

sweet, wasn't sure if it was ohc or pushrod. thanks. I still cant figure out why honda has to use timing belts. chains are better

Actually I prefer belts. I just lost my Nissan Altima due to a broken timing chain. There is no scheduled replacement for chains, and after 160K miles mine broke. I bent 12 valves and put holes in two pistons and a broken off valve actually lodged itself into the combustion chamber. Untill then I had no trouble with the car. I drove home from work, was pulling into the garage, and head a rattling sound. I popped the hood and it sounded like my water pump bit the dust. Next day I started it to move it to get a better look at the pump, and it stalled. I knew then that it was toast. My mechanic bought the car as he wanted to rebuild it, and the car owed me nothing. That and I did not want to spend $4000 on a car that was worth $1800.

 

[madmanmaigret]

Actually I prefer belts. I just lost my Nissan Altima due to a broken timing chain. There is no scheduled replacement for chains, and after 160K miles mine broke. I bent 12 valves and put holes in two pistons and a broken off valve actually lodged itself into the combustion chamber. Untill then I had no trouble with the car. I drove home from work, was pulling into the garage, and head a rattling sound. I popped the hood and it sounded like my water pump bit the dust. Next day I started it to move it to get a better look at the pump, and it stalled. I knew then that it was toast. My mechanic bought the car as he wanted to rebuild it, and the car owed me nothing. That and I did not want to spend $4000 on a car that was worth $1800.

I see where you are coming from, a salesman where i work has a tacoma w/220k miles on the clock and we asked if he ever had the timing belt/chain done. He said he never heard of it but would ask his mechanic, the mechanic told him they don't need to be changed which concerned me. now I will tell him to check another mechanic. I see where chains are stronger but they still have a service life. Thanks.

 

[wolfc70]

I see where you are coming from, a salesman where i work has a tacoma w/220k miles on the clock and we asked if he ever had the timing belt/chain done. He said he never heard of it but would ask his mechanic, the mechanic told him they don't need to be changed which concerned me. now I will tell him to check another mechanic. I see where chains are stronger but they still have a service life. Thanks.

Most manufactures do not have a recomended service interval. I believe the first gen Tacoma four cylinders (2.4L, 2.7L) have timing chains. The 3.4L V6 has a belt. The second gen has a timing chains. VW is the only company that has a specified inspection of the timing chains at 150K miles on the "W" engines.

My timing chain breaking is actually pretty rare on my KA24DE motor. My mechanic has never seen a chain break before, usually the guides wear and the chain just gets noisey. So I guess it is a horse apiece, have a regular serviced belt (can get costly if breaks) or a chain that should be maintenance free, but is noiser and is more difficult to replace if it goes, as there are less obvious timing marks on chain driven engines, that and the whole fron of the engine has to be taken apart.