Blue smoke on cold start and excessive oil consumption 2005 Tahoe

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Tahoe97

Member
Joined
Aug 27, 2013
Posts
50
Reaction score
32
We just completed a round trip drive between NC and FL running 10 straight hours in both directions at 75mph+ in our 2005 Tahoe (5.3L) . We have 270,000+ miles on the engine and it still runs great but historically uses more oil than normal. No oil leaks anywhere. Before the 1st 700 mile drive, I topped off the oil but had to add 1 qt upon arrival. Same deal on the return. Used 1 qt in 700 miles.

After the trip we started seeing blue smoke coming from the exhaust upon the 1st start of the day. We had not previously seen this after any long trips so this is a new development. After the 1st start of the day, any subsequent starts during the day do not produce the smoke. It has also not been as bad as the picture below which was the 1st start on the day after the 700 mile return drive. It has become less severe with each day but still remains to some degree.

I am seeing some online discussions that suggest the drivers side valve cover with the built in PCV valve is problematic on long extended drives with the original design allowing oil to get through the PCV valve system and into the combustion chamber. Is this in fact a possible cause?

The dealer suggested we may have a stuck ring and actually recommended putting 1 qt transmission fluid into the oil to clean out any carbon buildup in the cylinders and then after about 400 miles change out the oil again. Does this make sense or is this not wise?

Any and all recommendations are welcome. Thanks!

05 Tahoe blue smoke 10-28-20.jpg
 

wjburken

Supporting Member
Joined
Dec 26, 2017
Posts
9,705
Reaction score
26,282
Location
Eastern Iowa
To answer your question about putting transmission fluid in your oil, it is not unheard of to put a quart of it in as the mechanic suggested.

Might try and put a catch can in between your valve cover and your intake to catch any oil that may be getting pulled through there.
 

Mudsport96

Full Access Member
Joined
Jun 6, 2020
Posts
1,145
Reaction score
1,736
Location
40.923,-89.488. Illinois
The Silverado that I got from the father in law did something similar. After sitting overnight it would burp a blue cloud on start up, but not on consecutive starts that day. So hit the local pull-a-part and snagged a valve cover from a 99 to 02 truck, cleaned it good and put it on with a new pcv valve from an 01. It took a couple weeks to clear up, because I assume there was residual oil in the intake manifold. But that was 3 years ago, I now have the truck and my daughter drives it with virtually no smoke on startup. You can smell a hint of it, but at 400k miles what can you expect? I'm sure at this point the valve guides are worn pretty good lol.
I also did this mod on my 06 Tahoe after seeing the results on the Silverado. Figured I'd just get out ahead of the issue.
 

Scottydoggs

Full Access Member
Joined
Dec 16, 2017
Posts
2,500
Reaction score
3,619
Location
NJ
thats going to be dead valve seals with those miles.

what you say its doing is exactly what bad seal do.

you could fix it your self, if your ok with taking the rockers and springs off, then you can replace the seals. hell id do new springs while your in that deep too.
 

89Suburban

Bull in the china shop
Supporting Member
Joined
Jan 10, 2013
Posts
12,829
Reaction score
35,142
Location
SE PA
thats going to be dead valve seals with those miles.

what you say its doing is exactly what bad seal do.

you could fix it your self, if your ok with taking the rockers and springs off, then you can replace the seals. hell id do new springs while your in that deep too.


Yeah same thing a guy I work with with the same truck needs new valve seals. His is like twice as bad as that. I told him about the catch can but it didn't make a difference. He is putting new valve seals in it soon.
 

Scottydoggs

Full Access Member
Joined
Dec 16, 2017
Posts
2,500
Reaction score
3,619
Location
NJ
Yeah same thing a guy I work with with the same truck needs new valve seals. His is like twice as bad as that. I told him about the catch can but it didn't make a difference. He is putting new valve seals in it soon.

catch cans not even a band aid for bad seals. oil leaks down the valve stems either drops into the cylinder if its open or lays on the valve once fired up its a oil bath in the cylinders.

ive done em on my old car. but i only did em cause i was doing rockers and new springs, kinda silly to not change em on a 220 k mile engine while you can easily change em.

best to use a compressor to fill the cylinders to keep the valves from dropping, but you can also use rope, feed it in the plug hole then turn the engine over by hand till you feel it not turning. now the rope is pushing up on both valves and you can take the springs off.
 

89Suburban

Bull in the china shop
Supporting Member
Joined
Jan 10, 2013
Posts
12,829
Reaction score
35,142
Location
SE PA
catch cans not even a band aid for bad seals. oil leaks down the valve stems either drops into the cylinder if its open or lays on the valve once fired up its a oil bath in the cylinders.

ive done em on my old car. but i only did em cause i was doing rockers and new springs, kinda silly to not change em on a 220 k mile engine while you can easily change em.

best to use a compressor to fill the cylinders to keep the valves from dropping, but you can also use rope, feed it in the plug hole then turn the engine over by hand till you feel it not turning. now the rope is pushing up on both valves and you can take the springs off.


Yup, cloth rope right? Not nylon to scratch the cylinders.
 

Scottydoggs

Full Access Member
Joined
Dec 16, 2017
Posts
2,500
Reaction score
3,619
Location
NJ
dont think it really matters, but i have head of ppl using shoe laces, you know them 80's fat wide ones like run DMC wore lol
 

Forum statistics

Threads
128,781
Posts
1,805,301
Members
91,760
Latest member
MyCleftNut

Latest posts

Top