98 Jimmy - Coolant in Oil *Advise Please*

Im looking for some advice on a bad coolant leak that Ive got on my brothers Jimmy.

Lets start with whats happening. I just did the intake manifold gaskets on this engine, I had it running for a few minutes with the radiator cap off so it could bleed out the air in the system, after it was full it ran for a bit longer and started to overheat, I figured no big deal there must be some air still in the system not letting it flow right. It was low on coolant, but I noticed there was a puddle under the muffler, I thought maybe there was still some liquid in the exhaust from before the gasket change, but after running it for a while more and checking the oil, I can tell that coolant is definitely mixing with the oil, the oil on the dipstick is like a milkshake, and the coolant level keeps going down.

OK sorry for the long story, but here is the point and my question to anyone who can help, is there a way that I can definitively diagnose where the leak is, without taking the engine apart again??
Like I said, I just changed both upper and lower intake manifold gaskets, so it is possible I screwed up somehow.(the reason I changed the gaskets was because it had coolant coming up through the seal on the front drivers side between the manifold and head with no pressure in the system, just as you filled the radiator that was enough to force coolant out, so it was a major leak.) And I do know that on more than one occasion before this, my brother let the engine overheat majorly so it is possible that there is a blown head gasket, a cracked or warped head, or cracked or warped block.

Is there a way that I can find out where the leak is without pulling everything apart? Im thinking maybe a compression test on the cylinder could tell me something, but dont know if that info would even help. What do you think is the most likely suspect, did I screw up the gaskets, I dont see how I could have, but maybe there is some trick I didnt know about??? Well thats all, any and all help is apreciated. Thanks

You might be able to tell which cylinder is leaking by if you check the spark plugs to see if they have coolant on them. you can also do it with a compression gauge but you still have to take the plugs out. other than that i think you'll at least have to take the heads off again, or drop the exhaust down and run it to see which side the coolant is coming from and only take that side off.:smokin:

Did the engine get very hot before the intake gasket replace?
Did you use the hard steel and rubber problem solver gasket from felpro?

A quick test is to warm it up and drain oil and leave oil pan plug out.
Remove all spark plugs.
Then fill up with water and put a pressure tester on rad.and pump up to 17-20 lbs of pressure.
Watch for fast leak down.
If leaking down look for water running out doil drain plug hole.
And watch for water running out a spark plug hole.

If water running out oil plug hole or a spark plug hole.

Plull intake and check for messed up gaskets.
If it is ok you will need to pull heads and look for bad gasket or cracked head.

Also they make a block check head gasket tester that will show exhaust gas in coolant.
If it does not pass that test it is a head gasket or cracked head or block for sure.

Did the engine get very hot before the intake gasket replace?
Did you use the hard steel and rubber problem solver gasket from felpro?

Like I said, this isn't my vehicle and I wasn't driving it at the time, so I don't know for sure, but my brother said that it did get hot, just below the red, but not into the red, so like 240* ish. About a month ago his radiator blew because of a crack that he had ignored for a while, and I know that the temp got to the top of the gauge and it stalled out a couple times because it was so hot, and ever since it had been running kind of rough at idle and getting a "random and multiple cylinder misfire" code. This is when I think the warp/crack or blown head gasket could have occurred and just got much worse when it overheated when the manifold gasket went. Aparently, he tells me now, it has been steaming from the manifold seal since it overheated a month ago.

To answer the second question, I did use the felpro gasket, metal and rubber. I got the kit, I think called the problem solver kit, or something like that. Is there any special way of installing these gaskets? Ive done a couple other lower intake manifold gaskets on different vehicles and didnt have any trouble or problems. I will try the tests you suggested but it looks like Im gonna be tearing this thing apart again...

Not much of a way to mess up with the problem solver gasket.
They only go on one way.
Run the head gasket test before tearing down.
Good Luck

I would recomend doing a compression test on each cylinder and see where your loosing compression. If its was run hot for even a short while, chances are that is what caused it.