Coolant Leak Between Head and Block

[richard wysong]

 if you want to take the time to give the cooling system a flush before you refill it you can change to regular antifreeze. 1 of the bad things about Dexcool is its very corrosive when exposed to air such as low coolant level or seeping hose connections. its fine in a tight system though

[EightTrackHits]

16 hours ago, richard wysong said:

 if you want to take the time to give the cooling system a flush before you refill it you can change to regular antifreeze. 1 of the bad things about Dexcool is its very corrosive when exposed to air such as low coolant level or seeping hose connections. its fine in a tight system though

I had two gallons of dexcool given to me.  I’m likely going back with it this time in order to save some money on this project.  It’s kind of hard to troubleshoot with though, it mixes with the oil a little more readily, also incompatible with the UV dyes that most parts places keep in stock.

[EightTrackHits]

Quick update to say that I got the replacement head on last night.  One thing that is making it a little easier this time is I took the fender liners out and I lower the front end with the tires off on jackstands so I can reach a little better.  I’m going to work on this slowly, I have a few things going on.  Hope to be done by Friday and then I’m going to start a thread on rustproofing.

[EightTrackHits]

Just finished up.  Initial indications are I still have a problem.  Had plenty of white smoke on start up, it diminished some but never went away.  After an initial idle period, I ran the RPMs at 2000 to get it up to temp.  It sounds good.  I expect some problems from the sludge that was in the engine and the liquid that was already in the exhaust.  I’ll drive it some and see what the coolant level does.  If it stays up and the smoke goes away, I’ll be happy.  I was very careful.  We’ll just have to see.  
I included a pic of the exhaust. I had it running into a blower,  it even has some water pooling under it.

[richard wysong]

some condensation is normal this time of year and there is some coolant in the exhaust from before so take it for a blast and cross your fingers

[Brenden Burnham]

Perhaps get that liquid combustion leak test kit as that will tell you right away if there is still an issue.  The kit that uses fluid to test.

[richard wysong]

hows it going?

[EightTrackHits]

No progress guys.  I’ve been working out of town for bit.

[EightTrackHits]

Took it to work today, 30 mile round trip.  No noticeable coolant loss; vapor from exhaust was cleared up by the time I got there.  Oil pressure was around 40 at idle and 45 psi on the road.  Slight ticking noise was bothering me, but I’m almost certain that it’s the left exhaust flange.  
I’m going to park it till payday, change the oil again, and then run it for 250 miles or so and perhaps change it again.  

The engine may be compromised, so I may save for a reman, but who knows?  It may run well for many more miles.
I appreciate the people who viewed the thread and will continue to follow up if anything noteworthy happens.  Also going to start a thread on rust protection soon and I hope you guys will check it out.

[Brenden Burnham]

4 minutes ago, EightTrackHits said:

Also going to start a thread on rust protection soon and I hope you guys will check it out.

I no doubt will check it out.  

[EightTrackHits]

I took the truck to Eastern New Mexico from Indiana and back over the past few days.  No hint of coolant loss!  Fuel consumption was good for what this thing is, oil pressure was close to 50 psi at around 2500 rpm on the interstate and about 30 psi at around 600 rpm idle after warming up.

So, the repair is good this time.

 

I had the oil changed when I got to NM, the mechanic thought something was really leaking due to the fluid film underneath. 
 

I’ll follow up if anything noteworthy happens due to this repair.

[TyMechanic]

Anything ever happen after a long time? Just curious as I believe I have a coolant leak paired with a rear main seal leak. So I am about to become a mechanic out of thin air. I got my 2003 vortec 5.3 L that needs some love. After I spent christmas replacing gaskets on my valve covers figures.

Edited January 27, 2025 by TyMechanic

[richard wysong]

If you have Castech heads best to replace them

[txab]

 Do you know the leak is between head and block? Several places for leaks before jumping to Castech issue.

Water pump gaskets are very common. Crossover pipe on heads at front.  Throttle body hose connections

[TyMechanic]

Txab Well, I can smell coolant coming out of the exhaust, but no white smoke. It seems to have a sweet ish smell. The reason why I thought I had a coolant leak forsure was that my truck blew white smoke out when I started it one night.

However, it only did that one time for some reason so now I am confused. When I checked my oil, I found no milkshake, or no foamy white milky oil in my dipstick, or oil cap.

 

Guess ill just transition back to trying to fix my oil leak. Double confirming its my rear main and not some stupid sensor or something leaking by it. I looked one night at my oil pressure sensor with a snake light. It did not seem that was the cause of the leaks. However, once again it could be as I could not get a good look. My only 3 options for the oil leak seems to be a crank sensor above starter, oil sending unit sensor, or rear main. 

Edited January 30, 2025 by TyMechanic