Noticed a small puddle of coolant under the engine the other day. Looked further and found coolant on the intake just behind the thermostat housing. Assumed it was the thermostat housing but looking really close could not find any path where coolant had leaked; both bolts are tight.

Soooo.....anyone have a suggestion as to where the leak is at?

This is a 2002 4dr 4wd with the stock engine, no modifications.

Thanks in advance.

 

First guess would be lower intale manifold gasket...mine did something similar. It was leaking between vavle cover and intake and leaking down front of engine.
Double check by wiping area clean and letting run to temp while you check on it...might be able to see source. It is a common problem on these trucks. It is not an expensive fix if you can do it yourself.
If you do it your self there is a how to around here and be sure to get the fel pro gaskets with a 'T' in the part number.

Hope that helps ya find the problem

 

You know...I have seen references to the lower intake gasket leaking many times but I did not associate this with coolant leak only oil leaking.

So reading what was written above....describes almost exactly what is going on; leak appears to be coming from under the valve cover.

And yes I will be fixing this myself.

Ordering FelPro gasket kit tomorrow.

Thanks

 

As warthogdriver stated it does sound like lower intake manifold gasket,The 4.3L were notorious for the leaks..I have 2000 chevy blazer 4.3L and mine was leaking from the back of the lower intake and had it replaced 2 months ago.. I think GM should of had a recall on this but they never did...

 

Well under way in the intake gasket replacement task...

I have the intake off and separated the upper and lower intakes.

Question....how do the injector nozzles come out of the intake runners and how does the injector assembly come out of the intake? This is on a 2002 with the update injector spider. What is holding each injector nozzle and how do I release it? Is the injector assembly just pressed into the intake?

Thanks....I have lots...make that LOTS of cleaning to do.

 

the nozzles should just be held in there, look at them and there should be a couple tabs you press in to release them, as for the injector assembly, its basically just held in with a rubber piece that holds it in tightly (that is how it is on the first gen, should be about the same (even though diff engine)

 

Never could get the nozzles to come out.....gave up and cleaned-up the intake best I could and began the re-installation. No real problems...even got the fuel lines together with only minor difficulities. Not done yet...have to clean the throttle body but ran out of cleaner...so tomorrow will finish.

 

my o3 was leaking on ground in back of engine. intake bolts not very tight so i gave them a turn now leaking in cylinder. i need to replace intake gaskets

 

Be sure to see my post regarding Intake Gasket Set pricing.

Overall the job of replacing the intake gaskets is not all that bad. I did it over three days and took time to clean the intake runners which were coated with black tar-like substance....charr'ed fuel. Probably spent two hours just cleaning the intake runners.

There is a very detailed write-up, with pictures on this task that was extremely useful, especially in showing the two hidden nuts of the AC/power steering pump bracket that must be removed in order to slide the bracket forward.

I found the write-up on D-tips. Highly recommend finding it and reading through it several times before starting the job. I removed the hood for better access and light...and to avoid hitting my head!! The hood comes off so easily and it makes the job much easier.

The only other thing I would add is to pour some fresh oil all over the lifter valley area to wash off any coolant or dirt. I covered the area but did not want to take any chances for the price of a quart of oil. Then change the oil/filter afterwards before starting the engine.

I am currently letting the oil drip out of the pan....almost done.