[Farmstore34]

Here's one for y'all,

my son has a 1992 Chevy Silverado with the TBI 350. Just under 200,000 miles. When he first bought it I found the dreaded milky stuff on the dipstick, but also found that the t-stat was stuck open and the engine took forever to warm up. We changed the thermostat, flushed and changed the oil and filter. Now even with the engine running at 210deg we are still getting the white gunk on the dipstick. None under the oil filler cap or inside the valve covers however. He drives 15 miles each way to work daily, and doesn't lose antifreeze. Engine runs fine. Any ideas?
Thanks,
Colby.

[cool rockin daddy]

Could be condensation in the pan and engine that never gets a chance to burn off with such a short drive one way. Just a thought.

[dsraven]

the engines from those years had a problem with cracks in the block just above the lifters, from front to rear. my '88 had the same problem and I only found the crack when i took the intake off. there was a nice clean area where the crack was. in order to check for a leak, it is best to install a pressure tester on the cooling system, goes on where the rad cap is, then pressure test the system to the pressure written on the rad cap. usually 16 psi. pump it up and let it sit under that pressure and see if it holds or if it leaks down. if it leaks down, first check for exterior leaks. like a hose clamp or a water pump weep hole. if you don't find any external leaks, but the pressure won't hold, then you have a problem. if you are getting milky sludge on the dipstick then it won't be long till you are doing an engine, in my opinion. if you look at the underside of the pcv valve, is it milky as well? is it actually working? either way, you are getting too much water in there and need to find the problem before it is too late.
dsraven

[cobalt327]

Originally Posted by Farmstore34

Here's one for y'all,

my son has a 1992 Chevy Silverado with the TBI 350. Just under 200,000 miles. When he first bought it I found the dreaded milky stuff on the dipstick, but also found that the t-stat was stuck open and the engine took forever to warm up. We changed the thermostat, flushed and changed the oil and filter. Now even with the engine running at 210deg we are still getting the white gunk on the dipstick. None under the oil filler cap or inside the valve covers however. He drives 15 miles each way to work daily, and doesn't lose antifreeze. Engine runs fine. Any ideas?
Thanks,
Colby.

When you say "white gunk on the dipstick", do you mean all the oil showing on the stick is milky, or there's 'normal' oil showing w/a little milkiness above the oil level, or ? Do you see anything abnormal-looking in the radiator or coolant recovery tank like milky oil floating on top or mixed with the coolant?

There's a chance the intake gasket has started leaking coolant into the lifter valley. Hopefully it's not warped decks/blown head gasket or cracked head/block- but that's also a possibility, especially if it was overheated.

If he drives w/the oil contaminated w/water, obviously engine damage will occur, so best to get to the bottom of it sooner rather than later.

[CJ_1080]

Originally Posted by dsraven

the engines from those years had a problem with cracks in the block just above the lifters, from front to rear. my '88 had the same problem and I only found the crack when i took the intake off. there was a nice clean area where the crack was. in order to check for a leak, it is best to install a pressure tester on the cooling system, goes on where the rad cap is, then pressure test the system to the pressure written on the rad cap. usually 16 psi. pump it up and let it sit under that pressure and see if it holds or if it leaks down. if it leaks down, first check for exterior leaks. like a hose clamp or a water pump weep hole. if you don't find any external leaks, but the pressure won't hold, then you have a problem. if you are getting milky sludge on the dipstick then it won't be long till you are doing an engine, in my opinion. if you look at the underside of the pcv valve, is it milky as well? is it actually working? either way, you are getting too much water in there and need to find the problem before it is too late.
dsraven

I second this!! The intake gasket curse is on the 96 and newer vortec 350's. Not saying that it can't happen but I've seen a few with the cracked block above the lifters!

[Farmstore34]

Thanks everybody!

Yes, all the oil showing on the dipstick is milky. I think we will go ahead and pull the intake, and maybe even the heads. He can't afford a new motor right now and neither can Dad!

[cobalt327]

Originally Posted by CJ_1080

...I've seen a few with the cracked block above the lifters!

Happens when the engine is filled w/"coolant" that freezes.

[CJ_1080]

Good luck to ya!!!! Hope it is something simple!! I completely understand the shortfall of cash...especially when gas costs almost a half a paycheck to fill up!! Trouble always pops up up at the worst times!

[Farmstore34]

so if we need to replace the block, what years will fit this truck? I have a 1977 400 shortblock but I would want to make sure the heads and etc will bolt up before attempting. Or, what should I look for in a better replacement block?
Thanks!

[cobalt327]

Originally Posted by Farmstore34

so if we need to replace the block, what years will fit this truck? I have a 1977 400 shortblock but I would want to make sure the heads and etc will bolt up before attempting. Or, what should I look for in a better replacement block?
Thanks!

Do you have emissions testing, or do you plan on using the TBI and ECM, etc.?

[Farmstore34]

yes we plan to reuse the original TBI and ECM. no emissions testing.