4.3 V6 GM water loss

[B.G. Smith]

Coolant is going into oil pan while running, no evidence of water on plugs. Started slow but dramatically increased yesterday. Any suggestions where to start looking for the leak? bg

 

[Wayne M.]

Sounds like a Head Gasket, they don't only leak into the cylinder. The intake manifolds are known to rot out at the back and that would cause a coolant loss into the engine. Also check for an engine oil cooler in the rad, though if that was bad you would get oil in coolant too. This is a tough one to diagnose!

 

[B.G. Smith]

Thanks for the reply Wayne. I got the intake off today and can't really see any evidence of a leak. The center spark plug on both sides is clean but may be from recycling the water through the PCV valve. So much trouble to get the stuff off the top of engine to remove the intake, guess I will go ahead and pull the heads tomorrow. bg

 

[Wayne M.]

Being that you're going that far, look real good for cracks everywhere, examine the gaskets real good after you get them off carefully- look for rotted material, broken /blown out metal rings in the gasket, etc. Have the heads pressure checked at a good shop that does that type of work. Use good gaskets when going together.

 

[B.G. Smith]

Got the heads off and to the shop about 3:30pm this afternoon, he is going to boil them and check for cracks. I couldn't see anything that really was evident. The head gaskets probably looked better than the intake manifold gasket. I should know something tomorrow. bg

 

[Jim Fulmer]

B.G.

Let us know what the outcome is cause I have one too, also tell me if the intake gaskets are the same as mine, on mine they say to use the blocking tabs on the rear coolant holes(still don't undersand that one but it works).



Jim

 

[B.G. Smith]

Got the heads back this PM. They Magna-Fluxed the heads, said no cracks. They reground the valves,etc. and resurfaced the heads. I am going to Marshall Tx. tomorrow and coming back Sun. so it will be Monday before I get to start putting things back together. Will let you know how it comes out. bg

 

[B.G. Smith]

UPDATE. Got it back together after valve job. magnaflux, etc. Still getting lots of water in oil. Am going to try to pressure test the intake, heads next. As bad as it is leaking, it is not a small hole. bg

 

[bigkid59]

Some of these engines use an oil cooler that is sandwiched between the block and the oil filter.



The chances are that if you have this oil cooler and it is bad, you would have oil in the coolant due to the oil pressure being greater than the coolant pressure. However, it would be worth checking.



Good luck!!!

 

[B.G. Smith]

Oops! Took the air pressure off the block this morning and water level was down. Turned engine over by hand and #4 cylinder was full of water. Don't say much for the Magnaflux job I got. At least I have found a leak, now I can work toward correcting the problem. I am off to the deer lease till Sunday, guess it will be after Christmas before I get back on this project. Thanks to all for the responses and hope for you and yours a merry Christmas and a happy new year. bg

 

[Wayne M.]

BG, Don't condemn the heads just yet! You could have a porous or cracked block too! Put the piston down and look real good. You've made real headway in finding that water! Happy Holidays!

 

[B.G. Smith]

4.3 water in oil update

Finally found the problem in # 4 cylinder, about a 1 inch long crack about half way down the cylinder wall, also the piston for that cylinder was cracked at the pin down to the bottom of the skirt. Had to have some liquid in that cylinder somtime to do that damage. These blocks are hard to find so I had the cylinder sleeved and rebored the other 5 to . 030 in. oversize. Still don't have it back in the truck but the engine is assembled and getting close. Thanks to all who replied. bg

 

[Wayne M.]

Wow! talk about a flashback! I have a real hard time finding cracks in metal things like that. There's nothing wrong with a sleeve.