98 5.7l silverado burning coolant no leak evident help

sidewider,

thanks for reply. the oil is not a milky color yet. truck runs great as i stated and now still smells but using small amounts of coolant. maple sryup smell still in the engine compartment. i did check heater core for leaks and does not have the tell tale signs as fogging windshild and wet floor. truck has 108k and regular maintainence schedule is followed, oil every 3000. thought this might be easier than a new intake gasket kit. I would like to know if this is the next step and if it is are there any pointers before i start the work besides the usual drain the coolant, mark the connections ect... also, I'm wondering if the distributor will have to come out. I have not referenced the shop manual yet. i hate to distrub the dist.

thanks, btk

wrote

The distributor must come out. Because it's not necessary on this engine to "set the timing"...the best way to deal with the distributor is to first mark the position of the cap in relation to either the engine or the firewall. The cap has two long ridges on the top of it that run front to back.....I use these to make marks that correspond to them on the metal of the firewall. Then remove the cap and see where the rotor is pointing. Don't attempt to turn the engine over and get it lined up with #1.....just mark it's relationship to the firewall/engine in a way that will be easy for you to remember. Because the distributor in this model of Vortec v-8 is really nothing more then a cam sensor.....it's important to get everything lined back up, but there is no need to "fine tune" the position of the distributor unless you end up with service engine light on. If you mark it carefully and reinstall it as it came out...you wont have any problems.

You also need to remove one valve cover in order to get the intake manifold out.

You also need to remove the bolts and nuts that hold the drivers side (a/c and ps pump) bracket and slide it forward on the long stud that is located on the drivers side head. This is so that you can access one of the intake bolts that is underneath that bracket.

Do not attempt to completely get the wiring harness out of the way....just disconnect everything and then I usually bungee cord the harness so that it is suspended above the intake....you slide the intake out from underneath it.

Do not attempt to remove the fuel lines where they go into the upper plenum in the middle. Once you have the distributor out, it's easier to disconnect the lines right back at the firewall....leaving the fuel lines on the manifold alone.

There is a bracket that holds the wiring harness at the passenger side rear of the engine. Don't bother trying to get it completely out of the way. Just unbolt it where it is secured by the coil and then just move it up and out of the way. There is no need to attempt to unbolt it where it is secured to the rear of the head. You will note though that the bracket has a small tab right where it intersects the cylinder head/manifold area that sticks forward over the intake. You need to bend this tab out of the way, before you re-install the intake, otherwise it can interfere with the manifold as you are moving it into position. When you install the manifold you need to be able to move it into position while keeping slightly above the gaskets and the RTV at either end....before you lower it. Otherwise you can wipe the RTV off the ends and then you end up with a leak after it's all together. Typical newbie type mistake.

Ian

I would buy one of those leak detect kits, with the fancy light and glassess, It does oil, water and A/C. I bought mine last year for around $40.00 found a pesky A/C leak inside the car.

Its common for the 5.7 to leak from the right rear of the intake, coolant and oil. If you replace the intake gasket you will have to pull the distributor, just mark the position of the rotor in relation to the distributor itself before you remove it. Also when you get the intake off your might want to remove the EGR valve and clear the egr passages as they are probably full of carbon. When you have it al back together just set the timing and you'll be all set. Good Luck

"Mastermech" wrote

Please don't confuse the original poster. There is no timing to set on these engines.

Ian

If the distributor is removed then the base timing has to be set when it is reinstalled.

"Mastermech" wrote

and this:

It just looks to me like you are advising the poster to mark the position of the distributor and rotor and then once you have it all back together (which, if you install the distributor back into it's original position, "is" base timing) you need to set the timing. Which you don't.

Ian

You are correct. That is the base timing and it should be right on but if it were my rig I would put a timing light on it and make sure it was to spec. when I got done.

I appreciate all of the responses. First, I would like to say that I'll be tackling this progect in the very near future and I wiil provide a follow-up report.

I can already see an extra set of hands will come in handy. The details I got on removal will come in very handy. The timing issue has always troubled me. I've messed with the point and condenser type and what a pain in the ass, thus electronic ignition and distributors. I remember my '86' Ford f250 altough the distributor was electronic the timing had to be fine tuned with a timing light which I ended up power timing anyway for the best performance. I appreciate the refresher on marking the distrbutor and not disturbing the engine. I do belive I should get it as right on as possible, but I will resource the fine tuning part just to be sure. I have and old older friend mechanic but he tends to be a bit vague unless I'm real specific with him. This help narrow the discussion.

And yes, the oxidation I see is on the back of the engine, rt side. It only smells when the engine is hot.

I certianly would have disconnted the fuel lines at the manifold first.

Bungee cord tip on waring harness is great. I woud have and already have looked at removing completely.

I have had the plenum off and the harness disconnected. Nice to know I won't have to take of the water pump again as I did my first attempt to figure this out.

I hate to waste time making newbe mistakes. I sure have made my share of them and It always costs me double.

I'll save the glasses for the next leak and use the $ for the gasket kit but nice to know they are available.

Thanks again for all the tips,

BTK

that's a big 10-4 master mech. spec should be under the hood. seems like electronics would handle. that dist will be a pain to try and move while timing and running. Not quite out front like the old ford.

I 'd power time it running as i drve down the road. Just stop, pop the hood and kneel over the shroud. :)

"Mastermech" wrote

No, you don't understand....you cannot check the timing! What you see with your timing light will mean nothing! If you actually want to "time" it...ie: get it as close to base timing as possible, you have to use a scan tool and check what is called "camshaft retard offset"....which translates essentially to "base timing". The computer takes over from there. Remember, on these engines, what looks like a distributor.....is nothing more then a camshaft sensor, which can be moved on the v-8's but not on the 4.3 v-6's.

So for future reference, there is no point in advising folks with the vortec engines to "check their timing" as it is meaningless.

Ian

wrote

Unfortunately, Mastermech doesn't know what he's talking about when it comes to "timing" these engines. Please understand that you simply need to be careful to install the distributor "exactly" as it came out, ie: both the rotor and the body need to be in the same relationship to each other and to the engine as when they were removed.

If you do this, the timing will be right where it should be, if you get a "check engine" light coming on after you finish (note, the engine will still appear to run fine), then somehow you have changed the "camshaft retard offset", which is a fancy way of saying that the dist is not at base timing.

Please do not attempt to "power time" it.....this will not work on these engines. It's also not complicated to return the dist to it's original position if you just take some time to mark the cap and it's position to the firewall, and then remove the cap and mark the rotors position to something before you remove the distributor body. I've done literally hundreds of these and have only had the check engine light come on a couple of times...and that was always due to carelessness on my part

If you do happen to get the "check engine" light coming on, (always realizing that it might be something as simple as you left an electrical component disconnected) you may have to have a scan tool hooked up so that you can adjust the base timing (camshaft retard offset).

Ian