97 blazer multiple cylinder misfire
 

Hi. My 97 blazer 4.3 v6 is giving me all kinds of problems and hoping someone can guide me where to start. It's giving the code for random cylinder misfire. It has a rough idle, overheating issues, check engine light on and flashing. As well as losing coolent without a visable leak. No milky looking oil though. We have replaced the plugs, wires, distributer cap, rotor, radiator, water pump and thermostat. Any guidance would be helpful as we don't have much money or access to diagnostic tools.

If you are losing coolant, it must be going somewhere. How fast are you losing it?

The lack of milky looking oil could mean it is not a lower intake manifold gasket leak.

Have you considered the problem being a blown head gasket?

If I remember correctly, some of the symptoms would be white "smoke" (actually steam or water vapor) coming out of the tail pipe and/or the coolant system becoming pressurized. I wouldn't doubt that a blown head gasket could cause many other problems like the ones you've mentioned.

I could imagine that if pressurized, you would have coolant overflowing the overflow reservoir with some being pushed out of the reservoir.

Good Luck

We do have white smoke coming out and we are going thru a jug of antifreeze a day with only going about 10 miles. Is there any chance bars head gasket repair would help temporarily?

I'm not the greatest expert but it sure sounds like you have a blown head-gasket. I've never suffered from this myself so I do not have first-hand knowledge. What I have done is tried to educate myself on it so that I'll know it when I see it.

Here is a quote from the Bar's Leaks webpage I found:

"There is one bottom-line truth, no matter what any chemical tool company tells you: if your head gasket leak is too severe, no chemical repair will seal the leak. We’d love to tell you otherwise, but we’re always honest with our customers. If your leak too advanced, then you’re looking at a physical repair." https://barsleaks.com/gaskets/sympto...n-head-gasket/

If you are super desperate, you can try the chemical solution. I've never used them and normally I hear people suggest that no chemical "tool" should ever be considered a permanent solution. If I used Bar's Leak I'd consider it a stop-gap solution until a proper repair could be made. (Say on while on a cross-country trip.) Some of the practical considerations are if this is your only vehicle and you can't get by without it and if your current budget would not allow you to fix it or have it fixed.

The Bar's Leak page does have advice regarding which of their products can help depending on how quickly the vehicle overheats that can help you diagnose how bad your situation is.

The tough thing is that using overheating as a test is, in a way, a destructive test which is something to be avoided or at least minimized. You don't want to ruin your engine in the process of figuring out what was wrong with it!

If at all possible, the ultimate fix is to have the head gasket(s) replaced and also track down the problem that led to one or both of the gaskets failing.

Perhaps someone else on the forum can share their experience with Bar's Leak.

Good Luck

P.S. Here's a Youtube video from a mechanic about these products.

I just went through this with my 96. It turned out to be a bad distributor. $115 and I was back on the road. Was soooo bad for so long

Do you know in what way the distributor was bad? Worn bushings so that it rotated off-center?

Which misfire codes are you getting?

You should do a compression test. Make sure to remove all of the spark plugs first so that a leak between cylinders will be detected. A quick check is to disconnect the ignition and crank the engine. If the rotation has a lumpy cadence you my have a compression problem.

Do you smell coolant under the hood or in the passenger compartment?

You can also do a drop cylinder test which would help diagnose the pronlem. Let me know if you need help with this.

George

Distributor gears are made of softer material so they can't damage the camshaft. They get worn and loose and cause the timing to fall out of spec.

You may also be able to detect a blown head gasket at the radiator fill neck. One method looks for pressure fluctuations with a gauge and the other tests the coolant.