LIM and/or head gasket

Hi everyone.
I know the LIM is shot and has been for some time. I've been losing coolant on both sides (gunk build up). I've dumped the stop leaks in there for a while and now it's time to change the gasket. Changing the LIM gasket is about the extent of what my mechanical skills can handle. Therefore, I don't want to do the LIM job just to find out the head gasket or head is shot. The latest problem is steam comping out from just below the thermostat housing. Obviously antifreeze but is that the head or the LIM gasket? The car only begins to "overheat" when the antifreeze levels start to god down. Does this sound like the LIM only? What other symptoms would I have if the head/gasket were going or gone?

Thanks

Currently, it sounds like the head gaskets are still holding. Don't expect that to last forever. If you don't want to tackle the heads, do the LIM now, don't wait -- its only going to make the engine worse the longer you wait.
When the head gaskets start to leak, you will get coolant coming back into the overflow bottle due to the gas pressure. That won't get better with time or stop leak. (that stuff is bad, bad, bad imho).

You can do the LIM for the price of a kit (maybe $50) and a few hours work. That will solve the immediate problem and preserve your engine until you feel up to tackling the heads or can afford to have it done.
I think any 3.4L chevy with 100k miles give or take needs the head gaskets replaced and the heads checked for leaks.

Thanks for the reply.
Here's one more question: suppose I'm capable, and from what I've read I feel I am, to handle the replacement of the LIMG. Would the heads also be something I could handle or would that be a little too advanced?

Thanks

You mentioned you have been losing coolant for some time.

If the gaskets have been breached and you kept driving, the chances are the crankshaft bearings are being eaten.

This is not a good thing and unless you DO have the knowledge and tools to replace these components it's going to be difficult and may well wind up in a shop anyway.

Personally, I sure wouldn't want to go through (God only knows how much) time, effort and expense of replacing the LIMG, putting everything back together to find the engine noisier than previously thought, resulting in going through all that again, PLUS tearing it down to the ground to do the rest.

FWIW and FYI, an LIMG replacement job on this engine costs between $700 and $900 at a reputable independent shop.
The LIM part takes 6 hours of labor. Double that (& plus) if you have to do it again.

It's for this reason people tend to do a complete rebuild if it is suspected the bearings may be damaged from the oil/coolant mix as the labor is cheaper in the long run.

Put another way, it's similar to doing a timing belt and water pump at the same time. (NOT on this vehicle though, as the 3.4L has a timing chain)

I paid my independent tech/shop $660 CDN for the job (that includes the gasket kit, our taxes, oil/filter change, total coolant replacement and disposal fee ($2) plus other seals and hose clamps.

There is a LOT involved when rebuilding an engine and there are specs that must be followed closely.

Merc81 knows what I mean.

After reading the engine tear down and rebuild procedure in my Haynes manual (for the 3.4L) it seems to cover all aspects of the job.

Not being a tech I wouldn't swear to it. I'll tell you right now that I wouldn't attempt it.

For a start, the engine and transaxle has to come out the bottom, not out the top of the engine compartment. That's a reversal of the factory installation.

The (vehicle) bodies are dropped on to the frame over the engine, transaxle, etc.

Most techs I've spoken to and have read about suggest you have the proper safety equipment and facility plus factory manual at your immediate disposal.

Thanks again.
I'm going to try and do the LIM gasket and dump the $200 in parts into it. I guess I look at it as a risk reward. At worst I'm out $200....and a ton of my time. If it works, then I saved quadruple that.
I'm sure it's that and wishful thinking on my part.

We had a 99 Venture we sold last year with 209k mi. and the head gaskets were never done and it ran like new when we sold it. Still see it running around town a year later.

We had a 99 Venture we sold last year with 209k mi. and the head gaskets were never done and it ran like new when we sold it. Still see it running around town a year later.

Maybe the '99 model year was better :)

My '99 Montana has 185,000 miles, had the IMG replaced twice under warranty when my in-laws had it (last was the latest revision on the IMG, nearly 90,000 miles ago). I didn't see anything in the records that indicate the head gaskets were done, so I'm assuming they are original. Doesn't drip or burn any oil, but have a small antifreeze leak from the drivers side radiator area, either hose clamp or radiator, I haven't pinpointed this yet. 1-2 drops under the van every morning. I'm guessing it is the seam where the plastic meets the aluminum on the radiator...plastic...what ever happened to the all metal radiators?

Well heimdawg, there you have it; a range of opinion as to whether your should replace the LIMG or not. Only you can make that call. You sound like you're up for it so maybe you should give it a weekend effort. I checked for you and the kit currently costs $47.95 + shipping (1aaauto.com, #1AEIM00014). That gets you new gaskets and new bolts.
You will need, or should borrow a crow's foot 10mm wrench for the job, read the posts about it on these forums.

Its a tedious job, not a difficult one. You might need to do the heads, but you won't really know that unless you go ahead and do them and that job takes twice as long.
It gets done without removing the engine btw. I don't think anyone should change head gaskets without having a friend who has done it before on hand for advice 1st time.

Your options are: do nothing (not a good choice)
do the LIM (cost you $50 and a weekend)
do the head gaskets (cost you $120 + 3,4 days 1st time)
have it done at shop (you see the price above just for the lim)

I'd do the LIMGs. Seems like a simple choice to me.

Thanks merc81.
Actually the LIM was in my sights the whole time. I just wasn't sure I could handle the heads. Thanks for the advice. I've started another post and I'm getting a start today.

I think doing the LIMG properly is a lot more work and more parts cost than some posters make it sound like, but it is definitely doable if you have decent mechanic skills, and like the other posters said needs to be done ASAP.

Anyway run a compression test, and if compression is within spec then the headgaskets are OK. You can also get a chemical test kit from NAPA, or wherever else that carries it, that will test your coolant for combustion getting in it.

Get the new metal LIM gaskets, like Felpro's PermaDryPlus. And make sure you use the new LIM torque spec and tighten the bolts with an in-lb torque wrench, and use new bolts with threadlocker pre-installed. Also the new LIM outer bolts might require a 13mm crow's foot, at least the Fel-Pro bolts did.