2000 C 2500 Coolant in Oil

I have a 2000 GMC C 2500 4X2 with a 5.7 Vortec. It has 211,000 miles. I checked the oil in in lastnight and it was 4 inches over full and looked like it was muddy. I checked the radiator and it was about 4 inches low. I changed the oil and checked the compression and got got exactly 125 psi on all cylinders but one and it had 127. It got antifreeze in the oil just from turning it over to check the compression. Any one got any ideas where the antifreeze is coming from. Intake, head gasket, cracked oil cooler in radiator?? Thanks

I have a 2000 GMC C 2500 4X2 with a 5.7 Vortec. It has 211,000 miles. I checked the oil in in lastnight and it was 4 inches over full and looked like it was muddy. I checked the radiator and it was about 4 inches low. I changed the oil and checked the compression and got got exactly 125 psi on all cylinders but one and it had 127. It got antifreeze in the oil just from turning it over to check the compression. Any one got any ideas where the antifreeze is coming from. Intake, head gasket, cracked oil cooler in radiator?? Thanks

what did the plugs look like ? all the same color / burn ? any super white and clean ?

when the engine is running and the coolant cap off, rev engine do you get air bubbles in the coolant ..

disconnect engine oil cooler use 20 psi of air pressure test for leaks.

could be head crack. coolant with some cracks can dump into the crankcase ..this will give good compression but coolant in the oil...

Spark plugs all looked the same...brownish.

No bubbles in coolant when it is running.

I am gonna check the coolant tank tomorrow and let you know.

Thanks

Spark plugs all looked the same...brownish.

No bubbles in coolant when it is running.

I am gonna check the coolant tank tomorrow and let you know.

Thanks


If the coolant does not bubble with exhaust pressures[place a ballon over the cap hole ] , then remove valve cover[s] and inspect for coolant leak running down into the oil drain back hole , on top of the head.

Could be intake manifold gasket.
Any external coolant leaks?

Put a pressure tester on rad and see if it holds pressure.
If leaking off and no outside leaks drain oil and leave oil plug out and pump up pressure on rad and watch for coolant running out oil drain hole.

There are no external leaks. If the oil cooler is leaking on the side of the radiator, wouldnt there be oil in the coolant also? I looks bright green still. Havent had time to check the radiator yet.

I agree. Sounds like a Lower Intake Manifold Gasket to me.

I would just take it apart and once the LIM is off, check the coolant ports for signs of leaks past the gasket into the lifter valley.

If the LIM gaskets are original, they are probably WAY overdue. Fel-Pro makes an aluminum framed replacement set that does a good job. Also replace the LIM bolts. Fel-pro also makes a new set of bolts that will come with the right amount of threadlocker on them.

Im gonna start tearing it apart one of these days when I can find some spare time. I will let you know what i find. Thanks.

Im gonna start tearing it apart one of these days when I can find some spare time. I will let you know what i find. Thanks.

when coolant enters the crankcase you have no time !

coolant WILL rapidly destroy the engines internal components..

Wonderful! Good thing I have got a few other vehicles. I did start taking it apart just to look at it. What is the big black plug for right behind the throttle body? I unplugged it and there was about 1/4 inch of gas in the bottom of it. Is it some type of of fuel regulator or something.

Wonderful! Good thing I have got a few other vehicles. I did start taking it apart just to look at it. What is the big black plug for right behind the throttle body? I unplugged it and there was about 1/4 inch of gas in the bottom of it. Is it some type of of fuel regulator or something.

Are asking about the one where about 16 injector wires plug into top of intake and where the 2 fuel lines go in?

If so just plulling plug there should be no gas in it but if you had fuel lines un pluged the gas could have come from them.

If just wire plug in pull out and there is gas the injector body wiring is leaking or the seals on fuel lines.

with fuel line pluged in prime up fuel pressure and see if any leakage there.

Post back what you find.

I have not unhooked the fuel lines yet. Just unplugged that big plug.

I have not unhooked the fuel lines yet. Just unplugged that big plug.

OK
Blow/clean out old gas and prime up fuel pressure and watch for any gas leakage.
If lines not leaking check for gas leakage around injector wire pins.
Let us know what you find there.

It is coming up through the pins.

It is coming up through the pins.

You have a bad/leaking injector.
They can be replaced seperate if only one bad.

Try to find out which one and bend pin over so you can tell which injector it is when you take it apart.
Two pins for each injector.

If more than one injector is leaking.
I would replace all of them.

Let us know how it goes and good luck.

Would it hurt anything to put in new bearing while i have it apart? The antifreeze probably didnt do them any good did it? The intake was leaking on the passenger rear side. The gasket was actually broken in that corner and the pushrods and that whole area are shiny and spotless. Everything else looks like chunky peanut butter. Thanks.

Would it hurt anything to put in new bearing while i have it apart? The antifreeze probably didnt do them any good did it? The intake was leaking on the passenger rear side. The gasket was actually broken in that corner and the pushrods and that whole area are shiny and spotless. Everything else looks like chunky peanut butter. Thanks.

That is hard to say.

Hace you changed oil and filter and run it a while and rechasnge oil and filter?

How long did you run it with coolant in oil?
How much coolant was getting in oil?

Is oil pressure still good and any extra noises?

That is hard to say.

Hace you changed oil and filter and run it a while and rechasnge oil and filter?

How long did you run it with coolant in oil?
How much coolant was getting in oil?

Is oil pressure still good and any extra noises?


I ran it about 10 miles with coolant in the oil. The antifreeze was about 4 inches low and i checked the oil, it was about 4 inches high. The oil pressure was a little lower than normal. Right under the half mark. There were no noises and it still ran great. I did change the oil and filter and ran it for a few muinutes and was able to watch the antifreeze level drop. Thanks

I ran it about 10 miles with coolant in the oil. The antifreeze was about 4 inches low and i checked the oil, it was about 4 inches high. The oil pressure was a little lower than normal. Right under the half mark. There were no noises and it still ran great. I did change the oil and filter and ran it for a few muinutes and was able to watch the antifreeze level drop. Thanks

If you did not run it over 10 minutes with coolant in oil.
If mine I would change oil and filter and let run a while 20-30 minutes and the drop oil out and add new oil and filter.
Drive it and watch oil and coolant level.

Good Luck

I ran it about 10 miles with coolant in the oil. The antifreeze was about 4 inches low and i checked the oil, it was about 4 inches high. The oil pressure was a little lower than normal. Right under the half mark. There were no noises and it still ran great. I did change the oil and filter and ran it for a few muinutes and was able to watch the antifreeze level drop. Thanks

with what occured I agree run it and see how it works out..this was all completed in a short period of time . my guess you good ..

with over 200,ooomi on this one, don't want to spend too much to keep running..

X3, I agree, No sence dropping the pan to put bearings in it if not needed. My guess is your probably ok. Best, like the others say, to change the oil out right away. I will usually buy cheap oil and cheap filter, use that after a LIM or head gasket job, then I will add seafoam to the crankcase, let it run until it reaches operating temp, then I change the oil again with good oil and a good filter. The seafoam absorbs moisture ie coolant.

Side note, funny how it seems like every summer I have a GM LIM gasket to change. First it was the GF's 3100 motor, the next summer my 3800SC, and last summer the 5.7 in the pickup. Funny thing was last summer I was joking to the g/f that summer is never complete without changing out a GM lower intake gasket. Next week the pickup filled the crankcase with coolant. Guess I should keep my mouth shut.

But glad you get it running again!

I took it out and got i taken apart lastnight. Gonna let it set in the hot tank a while to get the crud out of it. I know I probably shouldnt have worried about it with that many miles. But im gonna try for 200,000 more.

Well there ya go. Make it last. Good luck!