2000 C 2500 Coolant in Oil

[20GMC00]

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

[j cAT]

Originally Posted by 20GMC00

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...

[20GMC00]

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

[j cAT]

Originally Posted by 20GMC00

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.

[MT-2500]

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.

[20GMC00]

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.

[tblake]

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.

[20GMC00]

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.

[j cAT]

Originally Posted by 20GMC00

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..

[20GMC00]

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.

[MT-2500]

Originally Posted by 20GMC00

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.

[20GMC00]

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

[MT-2500]

Originally Posted by 20GMC00

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.

[20GMC00]

It is coming up through the pins.

[MT-2500]

Originally Posted by 20GMC00

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.