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Oil And Coolant Mixing.. 2004 5.3l Silverado

JRD761

By JRD761
in Ask A GM Technician

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JRD761 Enthusiast

JRD761

Posted
Posted

I've got a 2004 Silverado 1500 with the 5.3L V8 engine and around 85,000 miles.

 

I've noticed over the past couple weeks that my coolant level keeps getting low.

I'll top it off, then in a couple days, it's back to where it was.

 

I don't notice it leaking anywhere. There are no drips in my driveway, I don't smell burning coolant, and I don't notice anything leaking from anywhere.

 

Today I checked it out a little better. I pulled off my oil filler cap, and in the plastic tube that comes from the valve cover to the oil filler cap there is a bit of cream colored sludge.

 

I changed my oil around 2,000 miles ago and none sludge of this was there...

I checked the oil level on the dip stick and it looked fine.. the oil didn't look dis-colored or anything, and the level is just fine.

 

I started up and couldn't tell if its smoking or not.. it's pretty cold out here and all cars tend to let off a little steam or something that looks like white smoke when its cold, so I can't really tell if it is smoking or not.

 

The truck does not overheat at all.. just sits at it's normal temperature and never goes over or under it.

First question: What do you guys think the posibilities could be? Head gasket? cracked head? something worse?

 

IMG_0005.jpg

 

That is what is in the oil filler tube. I haven't gone further into the motor to see if there is anything elsewhere.

 

Second question: I saw a TSB about Castech heads having a tendency to crack on these trucks. If this is my problem, would my truck (a 2004 at 85,000 miles), be covered under some type of warranty extension because of this TSB? Or is Chevy not covering anything at all?

jro909 Senior Enthusiast

jro909

Posted
Posted

if it castec heads, you are sol and will have to fork out your own money for the repair

JRD761 Enthusiast

JRD761

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I just replaced the water pump gasket last month because those were noticeably leaking.. was getting a puddle in my driveway, could smell hot coolant.. and was loosing coolant very fast.

I replaced it (and I made sure the coolant system was filled properly and all the air-pockets were removed) and that's when this all started.. but I'm not getting any leaks. There has been nothing on my driveway at all, nothing in the parking spots where I park it, and I don't smell the hot coolant thing anymore...

 

But my thing is, if I take it to the dealer, will they even do anything? I'm very strapped for cash right now (was laid off a couple months ago and haven't been able to find work) and can't afford anything right now. If the dealer will fix it for free then great.. but otherwise it's gonna have to sit until I get a job.

JRD761 Enthusiast

JRD761

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I took off the passenger side valve cover gasket today, and all appeared normal except for where one of the pockets where the head bolt is at in the middle of the head is filled with a milky/creamy color fluid.. the oil and coolant combination.. all the other pockets had oil in it which I am pretty sure is normal, but this one pocket is full of it kind of like the service bulletin about this problem said..

 

So, next question: Do you think if I grind that down slightly and apply JB Weld (for the right kind of metal.. are these heads aluminum or cast iron or what?) and would that fix it?

Or should I just get new heads?

JRD761 Enthusiast

JRD761

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Update:

 

I took the valve cover off again and took some pictures this time.

IMG_0002.jpg

(the green circle is the area where the weird colored oil was. There was still a good amount there, where the arrow is at)

 

Here are some other pictures.. maybe you guys can see anything wrong or abnormal or can tell if I even have the heads the Service Bulletin is talking about..

 

IMG_0013.jpg

IMG_0015.jpg

IMG_0019.jpg

 

I rented a coolant pressure tester from Auto Zone and put it on my truck.. pumped it up to 15psi, and let it sit for around 10 minutes.. it did not loose pressure and I did not notice any leaks or anything abnormal.

So I really don't understand where I'm loosing this coolant from.. (I may have over exaggerated on a post a little big ago.. I've probably lost about 1/4 of a gallon in the past couple weeks.)

txab Senior Enthusiast

txab

Posted
Posted

To identify suspect heads you have to follow the TSB to find the castech logo. The location you show is where the leaks shows.

minibike132 Senior Enthusiast

minibike132

Posted
Posted
I replaced it (and I made sure the coolant system was filled properly and all the air-pockets were removed) and that's when this all started.. but I'm not getting any leaks.

 

Don't JB weld it's not going to help you. Don't use stop leak, it does more harm then good.

 

IMO you are over thinking this. It looks to me like you have a little moisture mixed in there but moisture is not necessarily coolant. This is pretty normal, especialy if you are in a cold environment.

 

How do you know for sure you got all the air-pockets out? How did you bleed it? If you didn't use an air-lift or something similar then there is really no way to know. I would drive it and monitor the coolant and oil and see what happens. Even if it was coolant, that little trace you see wouldn't cause any issues (I still don't think it's coolant).

ken1mod Senior Enthusiast

ken1mod

Posted
Posted

If you drive short distances, combustion products contain water and would be normal. Not great but no problem either. Is your coolant level decreasing? Is you oil level rising? My old vw beetle did this horribly and it did not own a radiator.

 

Ken

rdnkcpa Enthusiast

rdnkcpa

Posted
Posted

Most likely you have the dreaded Castech problem. If so your heads will need to be replaced. My truck is a 2004 with a 5.3 with 114,000 on the odometer. This fall I noticed coolant loss, no leak, lifter noise on start up, and a weird temp problem every now and again. Did a search on this handy dandy board and found about the Castech problem.

 

Removed valve covers, passenger side looked ok, started to worry a bit. Worried that I pulled all that stuff off for no reason. I pulled the driver's side. The driver's side was full of the Dexcool/Mobil 1 sludge. Removed both heads and I took them to a machine shop to have pressure checked. Both heads failed. The machine shop ordered two new GM bare heads and is transfering old valves & valve springs to new heads. Valves are being reground to spec, replaced where necessary, springs tested and replaced as necessary. All new guides and seals installed. Cost $780.00 + valve grind kit.

 

I'm doing the installation myself and should have the truck back on the road in late January. I'm overseas until then. New heads will be waiting for me when I get home. Before I put it back together I'm going to replace the water pump just not to have to tear it all apart in the near future. It will also get new lifters, plugs, wires, belt, & hoses. I figure all the parts should come in for around $1,200.00. I have done some research, some dealers want around $4k for this repair.

 

No amount of JB weld, or stop leak will fix your problem. Only a new set of heads will solve your problem. If you have the Dexcool sludge, then you need to get the heads pressure checked to determine if they are toast. If I did not have the ability to do this myself I would have put it back together and sold the truck.

Bomber65 New Member

Bomber65

Posted
Posted

I just replaced the cracked Castech heads on my 2004 Sierra. The drivers side head was cracked and the valve cover had a creamy coating of oil/coolant. The crack was toward the front of the head. I'm wondering if the crack on others is from the drivers side head? The oil wasn't black like it should have been. It looked close to a fresh oil change. No milky look to the oil at all, but it did have a slight coolant smell. Lifter noise on startup. Puff of smoke also on startup.

 

After replacing the heads the truck started getting a P0327 and P0332 knock sensor code. I cleared it three times. Yesterday I unplugged the harness and plugged it back in (it appeared plugged firmly in) and cleared the code again. Drove the truck about 30 miles and no code has popped back up. But if you replace the heads, you might want to replace the knock sensors also since everything will be torn apart anyway.

 

I've been a GM person for quite a few years, but this truck may change that. So far I've had the transmission rebuilt, gauges repaired, heads replaced and soon to replace the ISS.

 

 

Update:

 

I took the valve cover off again and took some pictures this time.

IMG_0002.jpg

(the green circle is the area where the weird colored oil was. There was still a good amount there, where the arrow is at)

 

Here are some other pictures.. maybe you guys can see anything wrong or abnormal or can tell if I even have the heads the Service Bulletin is talking about..

 

IMG_0013.jpg

IMG_0015.jpg

IMG_0019.jpg

 

I rented a coolant pressure tester from Auto Zone and put it on my truck.. pumped it up to 15psi, and let it sit for around 10 minutes.. it did not loose pressure and I did not notice any leaks or anything abnormal.

So I really don't understand where I'm loosing this coolant from.. (I may have over exaggerated on a post a little big ago.. I've probably lost about 1/4 of a gallon in the past couple weeks.)

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