iamdub
Full Access Member
If it's a slow enough leak, the oil will look normal. The liquid will steam off just like normal condensation.
Air bubbles in the coolant reservoir
- Thread starter Doubeleive
- Start date
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If it's a slow enough leak, the oil will look normal. The liquid will steam off just like normal condensation.
Werd
Pull the valve covers and inspect!
MainelyScott
TYF Newbie
Just a thought, but I had a truck years ago and the head gasket was leaking. Couldn't tell until it got bad enough to smell at the exhaust pipe.
OP
OP
if it is a head and it's just sucking air into the coolant and not mixing in the oil then I can live with that until a deal comes along for another truck or a engine, preferably another truck. I paid $3k for this 04 about 5 years ago with 100k on it, has 240k on it now, been a good truck if I keep my eyes open I can find another one
A couple of years ago I had the same issue. I finally had to accept it had to be leaking internally. I put the pressure tester on and left it on overnight. I saw no drips, smelled no coolant inside, the rear heater core was dry.
I finally pulled off the valve cover gaskets and saw this in the thread linked:
https://www.tahoeyukonforum.com/threads/latest-oil-change-oil-filters.99646/page-4
It is important to note that this was NOT a Castech head. To spot this I had to:
Also note that if the leak is slow enough, the PCV will remove water from the oil before it becomes milk chocolate. However, over the period of an oil change, coolant additives and ethylene glycol can sludge your oil.
I finally pulled off the valve cover gaskets and saw this in the thread linked:
https://www.tahoeyukonforum.com/threads/latest-oil-change-oil-filters.99646/page-4
It is important to note that this was NOT a Castech head. To spot this I had to:
- Remove valve covers, clean suspect areas. Suspect areas are easy to find because leaking coolant partially cleans the area anyway.
- Install pressure tester and pressurize to 15 psi.
- Inspect for seepage.
- Final diagnosis: oil sample analysed and found evidence of coolant.
Also note that if the leak is slow enough, the PCV will remove water from the oil before it becomes milk chocolate. However, over the period of an oil change, coolant additives and ethylene glycol can sludge your oil.
Looking at the photo in that link I noticed the rockers still installed. The TSB on this indicates the castech casting logo can only be seen with the rockers removed. Here's a couple screenshots from the TSB.
I am currently experiencing this very same condition, although I also do not have the bubbles that @Doubeleive has. I have pulled the covers and found a leak/crack...
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That is true. Once I stripped the head of the rockers I was able to confirm there was no Castech logo.
OP
OP
I haven't pulled the covers off yet, it's going to get a oil change in the next couple of weeks and I have the blackstone kit now so I will see what the analysis says before I do anything.
Tonyrodz
Resident Resident
I'd like to see what's going on. My 4.8 with 862 heads on my work van keeps getting low. I need to add coolant about once a month--gets almost empty.
My drivers side cover told the tale as soon as was seen.... Passenger side showed some evidence but I failed to find a leak there.
Larryjb : Expected you would have noted finding any Castech logo somewhere in that thread, posted mainly for the sake of those not knowing where the logo is to be found. I haven't pulled my own rockers (yet) so I can't say whose heads I have other than 706 but I surely do have the leak(s)!!
Tonyrodz
Resident Resident
Still no milk shake in your oil tho? Did other manufacturers make 706 heads other then Castech? Did they make 862's also?
I never had milkshake. Milkshake occurs when oil is emulsified with water. If the leak is slow enough, the PCV removes the water quite well, but not ethylene glycol and additives (inhibitors/buffers). So instead, the glycol and additives cause the engine oil to sludge.
@Tj-baker, at the moment I cannot remember why I figured that I didn't have a Casetch head. It may have been that I didn't realize that there was a bracket covering the location of the Castech symbol, or if I was actually able to peer underneath that bracket. I remember looking for the Castech logo after everything came off and never found it.
Also, the cracked head (which was very obvious in the photos) actually passed the pressure test at the machine shop. The crack was small enough to be a slow leak, and only leaked once torqued down.
OP
OP
it has been tested 3 times, it was loosing pressure previous to the water pump being replaced, after the water pump was replaced it passed a pressure test, then about a month later while getting the oil changed at the dealer quick lube I noticed the coolant was low they topped it off and did a pressure test and it was holding fine, then a few weeks ago I noticed the crossover pipe leaking I replaced that with a new one and it hasn't been tested again since then but the pipe isn't leaking so it's going somewhere.
I'd rent a tester and put it on the test for half an hour or longer to see if you find the leak. Sometimes you have to find it on the ground first before you can look for the source.
For those who have the single crossover coolant pipe on the front, there are two coolant "plugs" on the rear of the engine that would have been used for the spider type crossover. Bottom line is, there are a couple of hidden leak potentials back there.
For those who have the single crossover coolant pipe on the front, there are two coolant "plugs" on the rear of the engine that would have been used for the spider type crossover. Bottom line is, there are a couple of hidden leak potentials back there.
OP
OP
ya that's one place I haven't checked yet had the transmission flushed and filter changed a couple months ago and the pan is leaking a little or I think it is, really hard to tell the difference between trans fluid and dexcool, i need to send it back to the shop that did the flush and have them do it again so i can rule it in or out.
