'99 Suburban 1500 started running rough now milky oil...Help!!!

[malibulvr]

My vehicle is a '99 Suburban with approx 126K miles. Engine is a 5.7 Vortec . Started running rough and got hot. No external water/coolant leaks but oil was milky. Changed the oil and filter and it ran fine again for a few minutes then started running rough again. I have searched and think it is the intake manifold that is leaking. I checked the compression and got readings on #1-#7 at 190[si, and #2..190psi, #4...180psi, #6...185psi, #8...190psi. I want opinions on whether I should remove the heads to make sure they are not cracked. Please help! Thanks and have a blessed day!

[MT-2500]

Originally Posted by malibulvr

My vehicle is a '99 Suburban with approx 126K miles. Engine is a 5.7 Vortec . Started running rough and got hot. No external water/coolant leaks but oil was milky. Changed the oil and filter and it ran fine again for a few minutes then started running rough again. I have searched and think it is the intake manifold that is leaking. I checked the compression and got readings on #1-#7 at 190[si, and #2..190psi, #4...180psi, #6...185psi, #8...190psi. I want opinions on whether I should remove the heads to make sure they are not cracked. Please help! Thanks and have a blessed day!

No 5 cyl also good?
Compression does not always show bad head gasket.
But.
A good chemical block check test on coolant system will show exhaust gas in coolant if head or gasket leaking.


A pressure test on rad will show intake gasket leakage.

They make a problem solver intake gasket that will fix the Gm plastic intake gasket problems.
All molded rubber and metal.

[malibulvr]

As I mentioned before I changed the oil out but after it ran a few minutes it is milky almost white again. A mechanic friend said that these systems would blow the coolant out of the radiator neck when cranked up cold if the heads are cracked. It does not do this and doesn't have bubbles in the coolant either. Also, when I removed the spark plugs, there was no coolant in the cylinders, or oil on the plugs either for that matter. I can easily change out the intake gaskets and such, but I am worried about the cost involved if the heads have to be replaced. I do not know how to do the chemical block check test on the coolant system. I do know how to do the basic radiator pressure test. I don't have a ton of $$$ to spend on this thing right now but need it fixed. Any help or instruction would be greatly appreciated.

As far as the compression test results:
When I did the compression test the engine was cold. All plugs were removed and the throttle body was held wide open. I pulled comp on each cylinder 3 times. The results were as follows:

#1...190 psi x3
#3...190, 185, 190 psi
#5...185, 190, 190 psi
#7...190 psi x3

#2...190 psi x3
#4...180, 185, 180 psi
#6...185 psi x3
#8...190 psi x3

[MT-2500]

Originally Posted by malibulvr

As I mentioned before I changed the oil out but after it ran a few minutes it is milky almost white again. A mechanic friend said that these systems would blow the coolant out of the radiator neck when cranked up cold if the heads are cracked. It does not do this and doesn't have bubbles in the coolant either. Also, when I removed the spark plugs, there was no coolant in the cylinders, or oil on the plugs either for that matter. I can easily change out the intake gaskets and such, but I am worried about the cost involved if the heads have to be replaced. I do not know how to do the chemical block check test on the coolant system. I do know how to do the basic radiator pressure test. I don't have a ton of $$$ to spend on this thing right now but need it fixed. Any help or instruction would be greatly appreciated.

As far as the compression test results:
When I did the compression test the engine was cold. All plugs were removed and the throttle body was held wide open. I pulled comp on each cylinder 3 times. The results were as follows:

#1...190 psi x3
#3...190, 185, 190 psi
#5...185, 190, 190 psi
#7...190 psi x3

#2...190 psi x3
#4...180, 185, 180 psi
#6...185 psi x3
#8...190 psi x3

You need to park it or fix it before you blow engine by driving it.
You can save money by a DIY on it.

Bad head gaskets can be bad 2-3 ways.
They may not always build rad pressure or lower compression or leak water into cylinders or engine oil.
A chemical block test is the best test for head on gasket leakage.
It will show exhaust gas in the coolant system from gasket leaking exhaust into rad.

Most good repair shops have them to test for head gasket leakage.
And will do the test for a fee.
Or you can buy one for 75-100$

Without doing the test to know for sure.
I would pull the intake and look for a bad intake gasket.
You can usually see it cracked out if old gmplastic gasket.
And always replace it with the problem solver molded rubber and metal gasket.
Good Luck
Let us know how it goes.

[malibulvr]

Just so that you know, I am not driving the vehicle and haven't since this happened, except to run it in the nieborhood after I changed the oil. I am planning on fixing it myself like I do with all of my cars, trucks, and racecar. I had already planned on replacing all of the the intake gaskets and it doesn't bother me to change out the head gaskets if they are bad, But if the heads are cracked I can't afford to replace them right now and I can still possibly sell it running and driving before I take it all apart. I can't get it to a shop without towing it because when I drove it in the neiborhood it started running a little hot after a couple of miles and don't want to chance it.

I don't mean to seem stupid about this, I am just old school. I am great with the engine and trans, rear end, etc... but when it comes to the newer electrical systems, the advanced cooling systems, I'm just not very good with them and have to ask for help. I really am just looking for proffessional opinion as to whether I should go ahead and pull the heads while I am there , or just replace all of the intake gaskets and see how it works. Oh, and I had already bought a FelPro intake gasket set from the local AutoZone but it has the plastic style head gaskets, so I guess I need to take them back and get the better style ones. Again thanks and God Bless!

[MT-2500]

At 126K and if it has not been real hot there is not much of a chance the head gaskets are bad.
Getting real hot is about the only thing that will crack the heads or burn the head gaskets.
It has been a long time since I have run into bad head gaskets on the 350 engine.
Many years back the 305 and 350 had some bad head bolts that caused head gasket replacement.
But not in many years.

Yes get the problem solver molded runner and metal intake gasket set of intake gaskets.
With them that should be the last time you will need to replace the gaskets.

Good Luck

[777stickman]

Compression looks good, what did the plugs look like?

[malibulvr]

The plugs look nice. No oil or water on the plugs either. I decided to go ahead and change out the intake gaskets and also replace all of the upper plenum gaskets also while I'm at it. I had bought the worng gasket set with the old style gaskets, so I took it back and got the better one with the steel inserts. I started pulling it apart this afternoon. I got most of the harness loose except for the crank trigger lead, the A/C compressor pulled away, and removed the alt., throttle body, all of the hoses, etc...I did find the oil fill cap had milky caramel colored stuff in it, and also the areas under the sensor thingys removed from the upper intake........I did one of these about 5 yrs ago when I bought a '96 Tahoe that had a burnt valve. I forgot how hard it is too get to the distributor and the fuel lines at the back of the engine. I hate these newer vehicles with all of these stinkin connectors and harnesses, not to mention all of the wierd vaccuum lines and such.

[MT-2500]

Originally Posted by malibulvr

The plugs look nice. No oil or water on the plugs either. I decided to go ahead and change out the intake gaskets and also replace all of the upper plenum gaskets also while I'm at it. I had bought the worng gasket set with the old style gaskets, so I took it back and got the better one with the steel inserts. I started pulling it apart this afternoon. I got most of the harness loose except for the crank trigger lead, the A/C compressor pulled away, and removed the alt., throttle body, all of the hoses, etc...I did find the oil fill cap had milky caramel colored stuff in it, and also the areas under the sensor thingys removed from the upper intake........I did one of these about 5 yrs ago when I bought a '96 Tahoe that had a burnt valve. I forgot how hard it is too get to the distributor and the fuel lines at the back of the engine. I hate these newer vehicles with all of these stinkin connectors and harnesses, not to mention all of the wierd vaccuum lines and such.

Yes the Alt/AC bracket is a pain.
The upper plamtium can be left on intake or removed.
Before you remove everything find TDC compression stroke and set engine there.
Then On seting dist back when you go together.

http://files.automotiveforums.com/ga...hp?photo=51302

http://www.automotiveforums.com/vbul...d.php?t=881442

Good Luck and let us know how it goes

[malibulvr]

I decided to dig into the engine this afternoon. I am somewhat pleased with what I found!

I started out with this:

By malibulvr at 2010-07-08

Look at what I found:

By malibulvr at 2010-07-08

I am going to guess that this is problem #1...

By malibulvr at 2010-07-08

And problem #2...

By malibulvr at 2010-07-08

So then I cleaned out the valley as well as I could...

By malibulvr at 2010-07-08

And then a trick I learned yrs ago to keep all the little stuff out of the engine...

By malibulvr at 2010-07-08

Later I got the gaskets removed and started cleaning up the intake and other parts, but then it got dark, so I stopped for today! Anyways, I'll keep you posted on the finished repair!

[malibulvr]

Thought I would update my progress..... I got everything cleaned up and reassembled the intake with the new style gaskets, didn't have too many problems. As far as the distributor.....when I was taking everthing apart, I marked the distributor position on the base of the distributor and a corresponding mark on the intake manifold with a paint pen. Also I removed the distributor cap and marked the position of the rotor tip on the distributor body, then removed the distributor. When reinstalling the distributor, I was able to line up the marks on the base of the distributor and the intake manifold, however the rotor was always a little off + or - from my mark. I tried moving one tooth either way and the rotor never would line back up just right on my mark. I settled for the dist body being lined up on my marks, and the rotor pointing just slightly to the right of my marl on the distributor body. Now that everything is back together, it cranks right up but runs rough, almost like it has fouled plugs or something, but I know they are good. I haven't tried to drive it yet, and am kind of afraid to. Also, the distributor drive gear looked like new without any wear, and as far as I could tell the distributor drive gear on the cam was also in good shape.

1st ???? Anybody have any idea why the rotor would not line back up. The engine was not turned at all during the repair.

2nd ???? How do I get it back set the right way. I can't afford a shop to repair it right now. I have to do it myself.

3rd ???? Is there a better way of getting all of the nasty milky oil out of the engine other than just changing out the oil 3-4 times. I want to get it cleaned out really good. I thought about maybe addding a half and half mixture of diesel fuel and engine oil to the crankcase and idle the engine for just a little bit to mix it up, then drain it. Maybe not , but if you have any ideas let me know! Thanks!

[malibulvr]

Woops....I just took time to read a previous post that I missed and the liks are great as far a setting the base timing. Thanks a bunch! I am still wondering about my ???? #1 and #3 though. Thanks.

[MT-2500]

Originally Posted by malibulvr

Woops....I just took time to read a previous post that I missed and the liks are great as far a setting the base timing. Thanks a bunch! I am still wondering about my ???? #1 and #3 though. Thanks.

Get it set on the base dist setting set as in link.
Then get it on a capable engine scanner and set camshaft retard setting as close to 0 degrees you can get it not over 1-2 -or + degrees.
Watch for codes and scanner readings.
If any scanner sensor readings are off find out why.
Also confirm good full fuel pressure.

[malibulvr]

Thought I would give a little update.....

I finally took the time to set the engine to TDC, then I removed the distributor cap and checked the rotor position. It was pointing about an 1/8th" to the right of the "8" mark. I loosened the distributor and adjusted it to line up correctly. Put everything back together and cranked it up. It still ran a little rough but it was better. After driving it a little it is running much smoother.

As far as cleaning out the milky oil residue from the engine. I changed out the oil and filter twice and it was still milky and nasty. After consulting with a few of my mechanic friends, I took their advice. I drained the oil, and then added 3-4qts of diesel fuel, and 2qts of ATF to the crankcase in place of engine oil. Cranked the engine and let it run at idle for approx one minute. Drained it out and put in fresh engine oil again. Ran the engine for about 30 minutes and the oil still looks nice. Finally!!!

So far no leaks, and it's not running hot or anything, so I guess I didged a bullet as far as the heads being cracked. I wanted to thank every body for the good advice as always! Have a blessed day!!!!

[MT-2500]

Originally Posted by malibulvr

Thought I would give a little update.....

I finally took the time to set the engine to TDC, then I removed the distributor cap and checked the rotor position. It was pointing about an 1/8th" to the right of the "8" mark. I loosened the distributor and adjusted it to line up correctly. Put everything back together and cranked it up. It still ran a little rough but it was better. After driving it a little it is running much smoother.

As far as cleaning out the milky oil residue from the engine. I changed out the oil and filter twice and it was still milky and nasty. After consulting with a few of my mechanic friends, I took their advice. I drained the oil, and then added 3-4qts of diesel fuel, and 2qts of ATF to the crankcase in place of engine oil. Cranked the engine and let it run at idle for approx one minute. Drained it out and put in fresh engine oil again. Ran the engine for about 30 minutes and the oil still looks nice. Finally!!!

So far no leaks, and it's not running hot or anything, so I guess I didged a bullet as far as the heads being cracked. I wanted to thank every body for the good advice as always! Have a blessed day!!!!

A COUPLE OF GOOD OIL CHANGES SHOULD HAVE CLEANED IT UP.
But it Sounds like it is on the road .

But you still need to get it on a engine capable scaner and check and set the camshft retard setting.

Good Luck