5.3 Coolant leaking to oil
 

Hello there fellow truckers. I'm usually a lurker for all the great knowledge forums offer, but I'm up against a situation that I'd like to find some enthusiastic help with.

The rig:

2000 Silverado 5.3 Z71
389, 000 km's
1 x rebuilt rear end
1 x rebuilt tranny
engine all original (except belts, plugs, wires, batt etc.).

Truck is an everyday use, well maintained work truck and traveler. Lots of medium towing (snowmobiles, bikes), and the odd heavy haul (broken truck or a tractor here and there).

Just noticed no heat the other day, thought the heat control under the dash was pooched as I just changed out the vent actuator a month ago. Then my coolant light came on, topped er' up, good to go. Went out for a hunt this morning, got back to the truck, coolant light again, wtf? It's gone, no smell, no leak, uh oh. Pull the dipstick sure enough, she's up about 2 liters of oil/coolant mix lol. So, obviously it's pouring rain right now and I gotta do this in my driveway. Plan on determining which head is cracked first before I go crazy, and will be doing some research and part gathering before I start too. So nice to meet you all, and if anyone has any useful info I should know about changing 5.3 heads, please feel free to email me!

Cheers,

Karl

Update
 

Update

So today I drained the old oil/coolant mix, and dumped in clean spare oil for now. Pulled both of the valve covers off. Both were badly built with fresh slime, I imagine this is the first spot for contaminated oil to condense and turn to jelly.

I was disappoint that I did not see an area on either head that looked clean to acknowledge a crack. I looked pretty good with a flash light too.

I'm not familiar with the water pump on these, are they a self contained pump, or is there a mechanical seal between it and the engine. (I just thought of this and its pouring right now so I didn't go look).

I'll continue to investigate, and advice is much appreciated!

I would suggest a compression test. Generally a leaking head or head gasket will show low compression on two adjacent cylinders. Sad to say, but with that kind of mileage a compression test may determine that your engine may not be worth repairing.

What daveb1 said, compression check. If you've got time, and some gaskets and a torque wrench, pull both heads and have them checked.

Actually, before that, pull our your spark plugs and look at each one for a washed look - it'll be super clean and perhaps fowled.

Dang - those thanksgiving turkeys get into everything!

LMAO!

Darn speel check.