Latest oil change/ oil filters

[Larryjb]

I just pulled the valve covers to inspect the head. It is not a Castech, BUT it is cracked in the same position that the Castech heads were cracking. Time for new heads.


In the oil drainback hole you can see the crack before I pressurized the cooling system. I already cleaned the area for clarity, but the area was already clean and shiny due to the coolant leak.


Same drainback hole, but after I pressurized the cooling system. I could see the coolant seeping into the crack in real time. There is no doubt the head is toast.


The Casteck logo should be between the two rockers on the right. If you search up the TSB related to the Castech head, you can find out what the Castech logo should look like, and where it should be located. There is no Castech logo here.


So questions remain, how much should I do? Funds are limited. I'm not interested in mods. I get a slight tapping for about 1 minute as I drive off in the morning, then it's smooth as silk. I'm considering leaving the lifters alone and just swapping the heads.

Oil analysis came back with good news, with the exception of the coolant in the oil.

 

[iamdub]

Since the heads have to come off to be replaced, I don't see why anyone in their right mind wouldn't replace the lifters. With the heads off, it's literally four small bolts (10mm heads, IIRC) to remove the plastic retainers and the lifters come right out. It's cheap insurance and you may be getting an advanced notice with the ticking at startup, so why ignore it? I understand funds being limited. But, when a lifter fails, you could be miles from home and it could wipe out your whole motor. That extra $100-$200 (or whatever lifters cost) and 20 minutes of labor would be a mere fraction of what such a failure would cost you later.

 

[Larryjb]

Up here in Canada, where everything can cost twice as much as in the US, not including the exchange rate, we have to question everything. Currently, I'm looking at close to $2000 for the heads, and that's with me removing and installing the heads. Now, that does include replacing the lifters.

My Mercury had an occasional lifter tap from the day I got it at about 40000 miles. It is now approaching 300000 miles with the same lifter tap. I've never had an outright lifter failure, but I've always changed my oil regularly and used synthetic.

That said, you're right that while I'm in this deep, why not change them? Well, cost is a much more significant factor in Canada than it is in the US. In our major cities we have professionals (teachers, police, etc) that cannot afford to live in the cities they work. Taxes have jumped so high now that some seniors that paid off their homes decades ago, are being forced to move because they cannot afford the taxes.

 

[swathdiver]

862 heads, is this a Gen III LS motor? Isn't this in the wrong section? @NathanJax

If those Canadian communists were in the desert and the sand was money, they'd run out of it in short order. I'm going to slightly disagree with my friend Chris, if money were tight, I'd leave the lifters alone. That motor does not look like it has been lubricated with synthetic oil for very long. On the other hand, conventional oil left in too long may have done this too.

 

[Larryjb]

It's a 2002 Tahoe, flex fuel.

I got it 2 years ago and started using synthetic when I got it. The shop will look at the condition of the rods to see if there is any sign of lifter damage. They found one head to replace the cracked one for about $150 and will transfer my hardware onto the new one.

 

[PNWMuseumman]

What ended up happening here? This was a fascinating read, especially considering that I only stumbled upon this thread while looking for people talking about Wix oil filters...

 

[Larryjb]

A machine shop has a replacement 862 head waiting for me. I have yet to remove the heads, but that should be happening soon. They are going to rebuild the heads once I get them off.

 

[Larryjb]

...
If your coolant loss is that slow, I don't see how it can be enough to remain in the oil and gunk it up. It'd burn off before that happened. Enough coolant in the oil to cause gunking should be visible by the classic "milkshake" appearance....

I thought I'd follow up on this comment. I had always wondered why GM coolant sludged instead of made the chocolate milk. This had been explained in an earlier post. I believe I have my answer. In the oil analysis report, there was evidence of antifreeze, but no water. This is most certainly because the PCV is doing it's job and removing water vapour from the crankcase. However, GM coolant contains organic "buffers" to control the acidity of the coolant. Many of these molecules will not be removed via the PCV and will remain in the oil. The organic molecule are probably polymerizing (making longer chain molecules) in the oil which is causing it to sludge up. All the coolant has to do is link several oil molecules together and voila, sludge. Other manufactures (Ford, I think Chrysler) use borate buffers to control acidity. These buffers will not polymerize, so if you had a coolant leak your oil won't sludge as it does in the GM engines.

Anyway, I'm still waiting to get time to tear into my job. So, no progress as of yet.

 

[Chubbs]

If coolant has been seeping into the crankcase over a period of 2-3 oil changes, there is always the possibility of lower end damage. I didn't see that topic discussed at all, but some would go the extra mile to investigate other areas possibly affected.

Well, a few oil changes that you know of. I'm starting to wonder if the previous owner had it diagnosed or encountered a sludge drain then ditched the truck ASAP. If you are hearing internal motor noise it could be the bearings for sure.

 

[Larryjb]

The coolant leak began last spring, but it is possible the PO used a coolant sealant of some sort. Also, the oil analysis showed all other metals were within normal ranges. So, I am taking a chance on the rest of the engine, but I think it's a pretty good chance.