Hey guys how's everyone doing
2003 Chevy Express 2500

The other day the truck overheated really hot like 260 when I open the radiator cap finally it was all gooey green stuff almost like baby s*** anyways it's oil in the water I'm pretty sure I've been pulling over and spraying it out at the car wash taking the upper hose off I tried head gasket sealer but apparently the water pressure is not as much as the oil pressure so the head gasket sealer material never makes it in the hole or the crack I have an idea though I want to run by you

Drain oil
Add diralub
Drive to carwash

Drain duralub

Leave oil resavoir empty
Put oil plug in truck

Clean radiator≥ fill radiator
Add bock sealer
Drive for 15 min
Add oil

I know it sounds crazy but it's the only way I can see getting the oil pressure less than the water pressure I just hope this doesn't put water in the oil

If there's anything at all you guys can volunteer or if you see anything wrong with my steps please let me know I'm going to try it tonight
Thanks

 

Don't mess around with sealers. If you get water in the oil it will kill the engine very quick. Find the leak and fix it. Do you have an oil cooler? Are you sure it's oil mixed and not transmission fluid?

 

Yes I have a cooler but the fact that it happened when I overheated makes that kind of not associated but going through three or four courts a dayof oil I haven't not dripped on the ground is probably proof enough and I already tried that but it didn't work I can see zero on the oil pressure gauge but it didn't work oh well I guess I have to pull the heads anyways thank you very much for your input

 

It might be worth getting a radiator pressure test kit to pressurize the cooling system with the engine off. You could do it drained and listen for the air leaking into the crankcase. Nice ones are expensive, cheap ones are less than $40 on Amazon from China, or you might be able to cobble something together yourself with an old radiator cap.

 

If there's ait leaking into the crankcase from the radiator wouldn't that put water in the crankcase or are we still working with the oil pressures greater than the water pressure
N
But I'll give it a try thank you
I guess I'll get a compression tester to
Where do u guys think the leak is the radiator holds water I checked this morning and it was only maybe a couple ounces low but remember I'm only running at 155 cuz I don't have a thermostat in so it hasn't really had a chance to get really hot

Let's say it's a head gasket what am I going to need at the store I know the gasket of course anything else you can think of anyways thank you for all your input I appreciate it very much

 

Question if I put something together myself I have an extra spout on the filler neck what kind of pressure are we looking at that I need to pressurize at

 

So I have the radiator empty and pressurized at right below 15 lbs I don't hear any hissing or air at alll

 

There's a lot more to replacing head gaskets than just throwing in the gaskets. You'll need a head gasket kit that will include the head gaskets, exhaust manifold gaskets, valve cover gaskets, valley pan gasket, intake gaskets and several others. You'll also need new bolts for the heads since they're single use "stretch" bolts that can only be torqued once. Be prepared to break off a few exhaust manifold studs too.

While the heads are off you should take them to a machine shop to have new valve guide seals pressed in and have the heads shaved to be sure they aren't warped. An overheating event in the past could have slightly warped the heads leading to the eventual failure. If you put it together with the heads still warped you could have another failure sometime down the line.

I would look up some videos of the process to see what you're getting yourself into. You should also check in on some LS motor forums for more specific info. Those forums are way more active than this one and may be able to help you narrow the problem down to something other than the head gaskets. The iron block "truck" motors are basically the same as the aluminum block LS motors. There's a lot of info out there on building an LS motor.

I've done head gaskets on several vehicles but not these specifically. It's a lot of work that has to be done properly with the parts organized so they go back in the same position. Good news is that the process is a lot more simple on these pushrod engines than on an OHC engine.

 

Air leaks through places that water or oil wouldn't. Did you put your ear up to the open oil fill cap? Compression test or better yet leak down tester is a good next step. Leak down is another way to listen for where the leak is going, this time from the combustion chamber.

 

Yes I used to hose down the oil filler neck and put it in my ear I didn't hear any leaks I'm on the 4th piston right now and so far left side is 60 lb f