Picked up a Blazer to fix up and use for a while. It's a '95 4x4 with the 4.3L

Issues:
*Engine doesn't seem very responsive just revving in neutral. - Most likely needs plugs(already replaced cap/rotor), or maybe vacuum leak.

*Coolant was full of rusty brown coolant(flushed and checked readiator, still need to flush block). I was thinking head gasket could have caused this, so some stop leak may have been added in the past. One of the plugs looked like it maybe had a green-ish tint to it. I have not yet done a compression test, but that is soon to follow.

I suppose my main question is how common are head gasket or intake gasket problems on these 4.3s? Or I could just be paranoid by coolant that is just old.

 

Talking from a little experience, sounds like you have a couple problems. A common power robber is your Catalyic Converter could be plugged. And yes, Intake gaskets leaking are common on them thanks to Dex Cool(replacing one as we speak). The greenish tint could be a head problem as well. Best to check compression first. If it reads over 150 PSI, it's the intake leaking.

 

So if compression is high I have an intake leak? That doesn't make much sense to me. But I've really never had any headgasket issues besides knowing it from water in exhaust, or starting car with radiator cap off and coolant shoots out.

I actually have yet to fire this thing up with the radiator hoses on. I've only taken it to the end of the driveway, but expect it should run a bit smoother and with more power than it does.

Thanks

 

Not necessarily. If the compression is around 150psi, that means that it is not your head gaskets which leaves the intake manifold gaskets as the next likely source of the leak. Unless the engine has been severely overheated, the head gasket is likely still intact.

LIM gasket failures are quite common given their construction. The plastic carrier on the gasket doesn't like too much torque as well as some other phobias. Felpro has a revised LIM gasket that has a metal carrier which gets around the short comings and incompatibilities of the plastic carrier. You still need to watch the torque values you use!

Rusty coolant likely means you have air in the system. If there is one thing that Dexcool doesn't do as well as the old green stuff is that it doesn't leave a film on the internal passages. If air is introduced into the system, it can allow for corrosion to set in. A few flushes should clean things up, but before all that, you have to fix the leak that allowed the air into the system in the first place.

Contrary to common believe, LIM gasket failures can be more attributed to the water in the cooling system than it can to the coolant. Inquiring minds can read through the rather lengthy, but very informative Dexcool thread. We don't need to get into that here. Please read through that entire thread before voicing your opinion. You may find that what you read alters your view point.

 

Just a bit of an update: Havn't got much done due to horrible work schedule and life in general. I got the Ignition module tested just in case, which turned out good. I'm going to say the plugs are ok since it didn't have any of this popping/hesitation before the transmission rebuild. So I'm going to proceed in the vacuum leak route. It may just be that this is a slow revving engine since I'm comparing it to vehicles with twice the Hp.

In either case, I still have a popping from the exhaust, but a rattle(converter area) showed up and since converters are not exactly required here I'm going to just pull it for "testing" reasons.

Updates to follow as soon as I figure out if that gets me anywhere.

 

Plug wires 1 and 3 were swapped. That is only trumped by the time I got the pressure and return fuel lines switched around when I converted over to AN fuel lines on my other car and I wondered why it would fire and instantly die.

At least I didn't have to mess with the converter. Top side is a lot easier on the back/body.